Impact assessment for the revision of the capacity allocation and congestion management rules : final report.
Date: 2025-10-21
Institutions: Directorate-General for Energy
Subjects: energy grid, energy transport, gas pipeline, gas supply, market access, natural gas, single market, transport network

Impact assessment for the 
revision of the capacity 
allocation and congestion 
management rules 

Final Report 

Ramboll, VIS Consultants 
July 2025 

 
 
 
EUROPEAN COMMISSION 

Directorate-General for Energy 
Directorate C — Green Transition and Energy System Integration 
Unit C3 — Internal Energy Market 

Contact:  Federico MARCO 

European Commission 
B-1049 Brussels 

 
 
EUROPEAN COMMISSION 

IMPACT ASSESSMENT FOR THE 
REVISION OF THE CAPACITY 
ALLOCATION AND CONGESTION 
MANAGEMENT RULES 
Final Report 

2025 

 EN 

Directorate-General for Energy 

 
EUROPEAN COMMISSION 

Manuscript completed in July 2025 

Final edition 

This document has been prepared for the European Commission however it reflects the views only of the 
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Luxembourg: Publications Office of the European Union, 2025 

© European Union, 2025 

The reuse policy of European Commission documents is implemented by Commission Decision 2011/833/EU of 
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PDF  MJ-01-25-132-EN-N 

 
 
 
 
Contents 

Introduction 

Abbreviations of key terms 
Executive Summary 
1. 
1.1 
1.2 
1.3 
1.4 
2. 
2.1 
2.2 
2.3 
2.4 
2.5 
3. 
3.1 
3.2 
3.3 
3.4 
3.5 
3.6 
3.7 
4. 
4.1 
4.2 
4.3 
4.4 
4.5 
5. 
5.1 
5.2 
5.3 
5.4 

Policy background 
Objective of the study 
Implementation of the study 
Structure of the study 

Measures for efficient use of gas networks 

Efficient use of gas networks 
Network planning 
Operational optimization 
Marketing of capacity 
Role of CMPs in the efficient use of gas networks 

Mapping of CMPs in EU Member States 

Application of the CMP Guidelines in the EU 
Rules and procedures to manage congestion at network points 
Harmonization of CMPs by adjacent TSOs 
Other mechanisms to manage congestion 
Congestion management at other gas infrastructure 
Utilization of congestion revenues 
Impact of decarbonization on congestion at gas systems 

Analysis of congested network points 

Overview of points selected 
Nature of the congestion 
Extent of unmet demand 
Application of CMPs 
Data validity and availability 

Regulatory shortcomings and potential interventions 

Areas of improvement 
Area of improvement: Definition of contractually congested points 
Area of improvement: Scope of the CMPs 
Area of improvement: Establishment of measures to manage 
congestion 
Area of improvement: Effectiveness and efficiency of the CMPs 
Area of improvement: Harmonization of rules between adjacent 
TSOs 
Area of improvement: Management of congestion revenues 
Area of improvement: Transparency 

Impact assessment of regulatory interventions 

Overview of the assessment framework 
Area of improvement: Definition of contractually congested points 
Area of improvement: Scope of the CMPs 
Area of improvement: Establishment of measures to manage 
congestion 
Area of improvement: Effectiveness and efficiency of the CMPs 
Area of improvement: Harmonization of rules between adjacent 
TSOs 

5.5 
5.6 

5.7 
5.8 
6. 
6.1 
6.2 
6.3 
6.4 

6.5 
6.6 

4 
5 
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13 
14 
14 
15 
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18 
19 
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82 

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91 

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6.7 
7. 
7.1 
7.2 
7.3 
7.4 

Area of improvement: Transparency 

Conclusions and recommendations 

Overview of examined regulatory interventions 
Impact of regulatory interventions 
Comparison of regulatory interventions 
Recommendations on the implementation of regulatory 
interventions 

Annex I: Country briefs on CMP rules 
Annex II: List of network points’ sides analysed 
Annex III: Case studies 
Annex IV: Survey on the impact of decarbonisation on the gas system 
Annex V: Survey on implementation of CMPs 

95 
98 
98 
98 
103 

107 
109 
176 
182 
208 
211 

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Abbreviations of key terms 

Abbreviation / Acronym 

Meaning 

ACER 

CAM 

CMP 

European Union Agency for the Cooperation of Energy Regulators 

Capacity Allocation Mechanisms 

Congestion Management Procedures  

CMP GL 

Congestion Management Procedures Guidelines 

EC 

European Commission 

ENTSOG 

European Network of Transmission System Operators for Gas 

EU 

FDA 

IP 

LNG 

LSO 

MS 

NRA 

European Union  

Firm Day Ahead 

Interconnection Point 

Liquefied natural gas 

LNG System Operator 

Member State 

National regulatory authority 

OS+BB 

Oversubscription and Buy Back 

SSO 

TP 

TSO 

UGS 

UIOLI 

UIOSI 

VIP 

VRF 

Storage System Operator 

Transparency Platform 

Transmission System Operator 

Underground Gas Storage 

Use It or Lose It 

Use It or Sell It 

Virtual Interconnection Point 

Virtual Reverse Flow 

4 

            
       
 
 
 
 
Executive Summary 

The TSOs are responsible for ensuring the efficient utilization of their gas network capacity, so that 
gas transportation through their networks remains as unimpeded as possible. Efficient use of the 
networks  can  be  enhanced  by  a  number  of  market-based  instruments  (such  as  offering  of 
interruptible  capacity,  over-nominations,  secondary  trading,  use-it-and-buy-it  services),  which 
facilitate the access to booked but unused capacity. As these measures may not be sufficient, the 
CMP Guidelines1 introduce additional mechanisms that seek to address contractual congestion. The 
oversubscription  and  buy-back  (OS+BB)  scheme  and  the  firm  day  ahead  use-it-or-lose-it  (FDA 
UIOLI) mechanism address short-term congestion, while the long-term use-it-or-lose-it (LT UIOLI) 
mechanism  and  the  surrender  of  capacity  aim  to  mitigate  underutilization  of  longer-term  firm 
capacity products. 

The objective of this study is to support the Commission in assessing the extent to which the CMP 
Guidelines and other related regulations have to be revised, in order to ensure an optimal use of 
the European gas infrastructure. 

Application of CMPs 

The Member States that were required to implement CMPs2 have put in place relevant rules and 
regulations.  All  these  Member  States  have  established  a  LT  UIOLI  mechanism  and  a  capacity 
surrender procedure, in line with the Guidelines. Short-term congestion is managed using varying 
approaches, including the activation of the FDA UIOLI mechanism, offering of additional capacity 
through oversubscription or reliance solely on market-based measures without releasing capacity 
using CMPs. In the latter case, provisions for the OS+BB mechanism are in place, to comply with 
the Guidelines, but no additional capacity is offered by the TSOs in practice. The different measures 
to manage congestion over the past 3 gas years are presented in the map below:   

Some adjacent TSOs and NRAs cooperated effectively to harmonize the CMPs applied at their shared 
borders.  Notably,  the  TSOs  of  Spain,  south-west  France  and  Portugal  agreed  on  a  common 
framework for applying an OS+BB scheme. Additionally, the NRAs of Belgium, the Netherlands and 

1 Commission Decision of 24 August 2012 on amending Annex I to Regulation (EC) No 715/2009 (link) 

2 The Member States not applying CMPs include Cyprus that has no gas market, Malta and Sweden that have no IPs, and 

Luxemburg that holds a derogation. 

5 

            
       
 
 
 
 
the UK drew up a joint vision on the implementation of the LT UIOLI mechanism, ensuring that its 
key features will apply in a harmonized way at their cross-border IPs.   

Although an OS+BB mechanism has been established in 18 Member States, only 6 (France, Greece, 
the  Netherlands,  Portugal,  Slovakia  and  Spain)  have  made  available  additional  capacity  through 
oversubscription since 2021. During the past 3 years, at several IPs of these countries where most 
capacity  was  already  booked,  the  TSOs  offered  additional  (usually  day-ahead)  firm  capacity  on 
multiple  days,  facilitating  firm  access  to  these  network  points.  The  buy-back  of  this  additional 
capacity by the TSOs appears to have been very limited, as they offered oversubscribed capacity 
when the users’ initial nominations were low, reducing the risk of high utilization of the booked firm 
capacity, or they made use of market mechanisms (e.g., interruption of interruptible capacity) to 
accommodate flow requests using firm capacity.  

In some Member States, the FDA UIOLI mechanism applies at all network points (Austria, Czech 
Republic,  Croatia,  Germany)  regardless  of  their  congestion  status.  In  others,  the  mechanism  is 
activated only at congested IPs (identified by the TSOs or included in ACER’s report). Renomination 
restrictions due to the FDA UIOLI mechanism resulted in capacity released mostly in Germany and 
Austria. 

In most countries capacity was surrendered from long-term capacity products, resulting in amounts 
of capacity released for a long period of time, and often throughout the gas year. In the past 3 gas 
years,  most  amounts  of  capacity  were  released  at  Czech  IPs.  This  surrendered  capacity  was 
reallocated on some days, mainly during the energy crisis in 2022, when the available firm capacity 
was not sufficient to cover demand. 

The  possible  activation  of  the  LT  UIOLI  mechanism  to  withdraw  systematically  unused  capacity 
works as a disincentive to network users to hoard capacity. In practice, it was used only once in 
2015, to withdraw systematically underutilized capacity at the Czech side of IP Cieszyn (PL) / Český 
Těšín (CZ). In the past 3  gas years, release of capacity was reported at IPs in Hungary and the 
Czech Republic, however this was associated with managing contractual issues at the IPs and not 
with capacity hoarding. 

Analysis of the experience and lessons learned with the application of CMPs has indicated that3: 

•  All  IPs  where  demand  for firm  capacity  exceeds  the technical  capacity  are  considered  as 

contractually congested, regardless of the actual nature of the congestion.  

•  Measures to manage unused capacity at LNG terminals and storage facilities vary among 

Member States. 

•  Market-based capacity measures (e.g., over-nomination) are often used as alternatives to 

manage short-term contractual congestion. 

•  Application of different congestion management measures at the two sides of an IP may 

• 

impact the use of capacity. 
The existing framework allows TSOs to use congestion revenues to decrease tariffs and/or 
invest in new capacity. 

•  Obligations  for  publication  of  information  relating  to  CMPs  could  be  further  detailed,  to 

ensure consistency and facilitate the network users’ decision making. 

3 The regulatory shortcomings and challenges, and the interventions to overcome them, were identified through a review of 
the CMP rules and procedures, a quantitative analysis of congested network points in the EU transmission systems, and 
interviews with NRAs and TSOs. The findings were validated and enhanced through a survey on the implementation of CMPs 
with the participation of key stakeholders (NRAs, TSOs, traders). 

6 

            
       
 
 
 
Regulatory interventions to improve management of congestion 

Taking into consideration the aforementioned experience and lessons learned, improvements in the 
design and implementation of CMPs can be considered in the following key areas:  

• 
• 
• 
• 
• 
• 

Definition of congested points 
Scope of the CMPs 
Establishment of measures to manage congestion 
Effectiveness and efficiency of the CMPs 
Harmonization of rules between adjacent TSOs 
Transparency 

These areas can be improved through targeted regulatory interventions, which seek to address the 
most impactful challenges and shortcomings. 

Definition of congested points 

The definition of contractual congestion in the recast Gas Regulation (EU) 2024/1789 identifies as 
congested,  the  network  points  at  which  the  level  of  firm  capacity  demand  exceeds  the  technical 
capacity. Network points with physical congestion are a subset of such cases. However, in situations 
of  physical  congestion,  where  the  technical  capacity  of  a  network  point  is  not  sufficient  to 
accommodate the users’ flow requests, the activation of CMPs to reallocate unused firm capacity 
would not resolve the system’s technical constraints. This would lead to an inefficient application of 
CMPs. The identification of contractual congestion should focus on cases where booked firm capacity 
is  not  being  used  optimally.  Such  a  definition  could  take  into  account  underutilization  of  a  fully 
booked network point, which other market participants are interested in accessing4. 

The  CMP  Guidelines  identify  as  contractually  congested  the  IPs  at  which  firm  capacity  was  not 
offered for at least 1 month. This criterion has led to some IPs being classified as congested even 
when  the  lack  of  capacity  offering  was  not  due  to  firm  capacity  being  fully  booked.  Such  cases 
included unavailability due to maintenance and works at the gas system, lack of an interconnection 
agreement between the adjacent TSOs, or use of the IP only in emergency situations. 

The criteria established in the CMP Guidelines to identify contractually congested IP sides should be 
re-examined,  to  ensure  that  they  reflect  actual  situations  of  inefficient  use  of  capacity.  The 
regulatory interventions examined to address this objective are presented below: 

4 Responses to the survey on the implementation of CMPs confirmed that the participating stakeholders consider this 

definition of contractual congestion as more appropriate than the existing one. 

7 

            
       
 
 
 
 
Scope of the CMPs 

Transmission network points 

The application of CMPs at transmission network points, other than IPs, depends on the network 
access rules applied at Member State level. For example, at interfaces of the transmission system 
with LNG terminals and UGSs capacity may be reserved by the operator and not by users, and at 
exits  to  distribution  capacity  may  be  managed  by  the  DSO.  Given  that  different  network  access 
conditions may be used at the Member States, a common EU-level approach for using CMPs at non-
IP  points  would  not  be  effective.  Concerning  the  application  of  CMPs  at  IPs  with  third  countries, 
these  apply  on  a  case-by-case  basis  by  the  TSOs,  depending  on  its  access  rules  and  operation, 
usually without coordination with the adjacent operator.  

LNG terminals 

At  most  LNG  terminals,  both  regulated  and  exempted,  there  are  already  measures  to  manage 
congestion relating to the terminal services (e.g., regasification, unloading, storage, etc.), which 
allow the operator to unilaterally withdraw booked but unused capacity of the users. Such measures 
usually  include  a  use-it-or-lose-it  or  use-it-or-sell-it  mechanism.  Nevertheless,  at  some  LNG 
terminals, capacity is returned only upon decision of the users through surrender and/or secondary 
trading. To ensure that the terminals’ capacity is efficiently used, an obligation could be introduced 
at  EU-level,  for  operators  to  establish  rules  allowing  them  to  withdraw  and  reallocate  unused 
capacity. The congestion measures applied at each LNG terminal should fit well to the operational 
framework of the particular facility. For this reason, any relevant obligations for operators should 
be set only on a high level. The regulatory intervention considered is presented below: 

Underground storage facilities 

The rules for accessing underground storages and the management of unused capacity vary among 
the Member States. Depending on the market characteristics, the access regime may be  regulated 
or negotiated, and a range of safeguard measures may be in place to ensure storage filling, limiting 
the commercial use of capacity. Usually, the use of storage capacity is confined to the respective 
market  and  has  limited  cross-border  impact.  Therefore,  harmonizing  the  use  of  capacity  and 
management  of  congestion  at  the  storage  facilities  on  an  EU-wide  approach  for  managing 
congestion at storages cannot apply in practice.  

Establishment of CMPs 

Activation of FDA UIOLI 

The CMP Guidelines link the activation of the FDA UIOLI mechanism with the IP sides identified as 
contractually  congested  in  ACER’s  Congestion  Report.  In  practice,  the  occurrence  of  physical 
congestion situations is not synchronized with ACER’s reporting, leading some NRAs to apply the 
mechanism at all IPs regardless of their congestion status, and others to oblige the TSO to monitor 
the congestion criteria themselves. With the Congestion Reports becoming biannual, the time lag 
will  increase,  and  the  activation  of  FDA  UIOLI  may  occur  significantly  later  than  the  actual 

8 

            
       
 
 
 
occurrence  of  the  congestion.  Decision  making  for  the  establishment  of  FDA  UIOLI  could  be 
separated from ACER’s reports, so that NRAs can swiftly activate the mechanism, by monitoring 
congestion at their IPS. The regulatory intervention considered is presented below: 

Flexibility in the application of CMPs and market measures 

For short-term contractual congestion, NRAs apply measures to manage congestion that fit their 
market and system operation. Some NRAs rely exclusively on market-based measures (e.g., over-
nomination, use of interruptible capacity, secondary trading), even though CMP rules are foreseen 
in their national regulation. Others combine such measures with FDA UIOLI or OS+BB mechanisms. 
The CMP Guidelines could provide for more flexibility and freedom to the NRAs when deciding which 
mechanisms  to  establish,  in  order  to  manage  day-to-day  contractual  congestion,  including  the 
possibility  to  apply  only  market  measures.  The  regulatory  intervention  considered  is  presented 
below: 

Mid-term UIOLI mechanism  

Regulation 2022/2576 introduced a temporary monthly UIOLI procedure, however the NRAs opted 
not  to  use  it,  as  they  considered  that  the  existing  measures  were  sufficient  to  address  the 
occurrences  of  contractual  congestion.  The  inclusion  of  a  similar  mechanism  in  the  Guidelines, 
focusing  on  capacity  with  mid-term  duration  could  be  considered,  however,  it  does  not  seem  to 
attract interest from stakeholders5, and is therefore expected not to add significant values in making 
operation of the gas networks more efficient.  

Impact of decarbonisation on congestion 

Decarbonisation  will  affect  the  use  of  the  gas  system.  Renewable  gases  may  impact  the  flow 
patterns in the gas systems, while repurposing, dismantling and decommissioning of gas assets will 
also  change  the  layout  of  the  European  gas  system.  It  is  expected,  however,  that  the  need  for 
additional CMPs to manage congestion, resulting from decarbonization of the natural gas systems, 
will be limited6. The existing CMPs are considered to be sufficient, while the occurrence of any new 
congestions, due to decarbonization, is expected to be physical rather than contractual. Therefore, 

5 Responses to the survey on the implementation of CMPs validated this view. 

6 Based on the responses received in a dedicated survey examining the relevance between decarbonization and congestion at 

the European gas system. 

9 

            
       
 
 
 
 
 
there is no added value in adjusting the CMPs in the short-term, to address changes in the use of 
the gas system, due to the transition towards a decarbonized gas market. 

Effectiveness and efficiency of the CMPs 

OS+BB and FDA UIOLI mechanisms 

Many TSOs are reluctant to offer additional capacity through oversubscription, due to the buy-back 
risks. As a result, the FDA UIOLI is used, an OS+BB mechanism is established in the Member State 
but is not used in practice, or additional capacity is offered only if nominations are low. The CMP 
Guidelines already include provisions that allow NRAs to apply incentive schemes to mitigate the 
TSOs’ risks. No additional adjustments are needed in the Guidelines, to improve the effectiveness 
of the OS+BB mechanism. 

LT UIOLI mechanism 

The CMP Guidelines are flexible in the key design elements of the LT UIOLI mechanism (definitions, 
activation conditions, capacity withdrawn, etc.). This can result in the mechanism being applied in 
an  uncoordinated  way  by  adjacent  TSOs7.  However,  the  limited  need  for  activating  such  a 
mechanism reduces the added value of implementing a regulatory intervention to address the issue. 

Surrender mechanism 

The TSOs do not allow capacity being surrendered to be at the same time marketed at the secondary 
market.  As  a  result,  the  two  mechanisms  are  directly  competing,  and  the  network  users  must 
choose whether to surrender or sell their capacity. Providing both options to network users could 
provide  for  more  flexibility  in  disposing  booked  but  unused  firm  capacity.  The  regulatory 
intervention considered is presented below: 

Harmonization of rules 

There are several cross-border IPs at which a different mechanism applies (OS+BB, FDA UIOLI or 
market-based measures) to manage short-term congestion at each side of the network point. The 
analysis of the CMPs’ application, carried out in this study, has not indicated specific cases of IPs 
where  the  lack  of  a  harmonized  approach  to  manage  congestion  has  resulted  in  considerable 
restrictions to the smooth operation of the IP. Nevertheless, the use of different mechanisms at the 
two sides of an IP can have adverse effects to the use of the IP’s capacity (limitations in bundled 
products, difficulties and confusion for the users, etc.)8. To manage such issues, the introduction in 
the  Guidelines  of  some  provisions  aiming  to  ensure  harmonization  of  the  applied  congestion 
measures, could be considered. 

7 Apart from a matter of effectiveness and efficiency, this is also an issue of harmonization of the applied CMPs. 

8 The possibility of adverse effects in case different measures are used has been highlighted in the results of the survey on the 

implementation of CMPs. 

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Transparency 

All information necessary to monitor the application of CMPs and to examine their effectiveness and 
efficiency is collected by the TSOs. Some information is published, and some is reported internally 
to the NRA. The analysis of the published CMP data has indicated some inconsistencies between the 
TSO’s  websites  and  ENTSOG’s  transparency  platform.  There  is  also  sometimes  CMP  information 
published that does not concern the release of capacity to manage contractual congestion. These 
cases  may  relate  to  the  limited  detail  of  the  transparency  requirements  set  out  in  the  Gas 
Regulation. Publication of additional information, such as the amount of released capacity that has 
been reallocated to other users, can facilitate the network users’ decision making when planning 
for the use of capacity. The obligations of the TSOs relating to the publication and transparency of 
the CMPs’ application could be further detailed, to ensure consistency and enhance the amount of 
information provided to the network users. The regulatory interventions examined to address this 
objective are presented below: 

Comparison of regulatory interventions and recommendations 

The regulatory interventions should be prioritized on the basis of their importance, applicability and 
relevance.  The  screening  criteria  examined  include  the  size  and  impact  of  the  intervention,  the 
extent  to  which  introduction  of  the  intervention  into  the  existing  European  legal  framework  is 
complex,  the  coherence  with  the  EU  policy  objectives  of  market  integration  and  access, 
decarbonization  and  security  of  supply,  and  the  proportionality  between  effort  and  benefit.  The 
comparison of the interventions against these criteria is presented below9: 

9 Rating of 3 denotes the highest rank and 1 the lowest rank. 

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The analysis of the CMPs’ application and the assessment of the regulatory interventions lead to 
the following conclusions and recommendations: 

• 

Priority could be given to revisions to the Guidelines and the Gas Regulation that focus on: 
o  Revising  the  criteria  of  contractually  congested  network  points,  to  introduce  a 
definition that  includes  the  IPs  with booked  but  unused  capacity  and  with unmet 
demand of network users for firm capacity. At the same time, the criterion of non-
offer of capacity should focus on cases of congested IPs. 

o  Prioritization of the use of market-based measures and allow activation of OS+BB 
or  FDA  UIOLI  only  if  needed,  in  case  the  market  measures  are  not  efficient  or 
sufficient. 

o  Extend  the  TSOs’  publication  requirements  for  CMPs,  to  include  additional 

information and further detail the existing obligations. 

•  Other revisions to the Guidelines, considered with a lower priority, include: 

o  Activating  the  FDA  UIOLI  mechanism  based  on  NRAs’  monitoring  of  congestion, 

instead of using ACER’s Congestion Report. 

o  Setting an obligation to NRAs to monitor the application of different measures to 
manage congestion at their cross-border IPs and apply changes to these measures 
if these are hampering the harmonized use of capacity. 

•  At  the  LNG  terminals,  a  revision  of  the  Gas  Regulation or  the  Guidelines  could  introduce 
high-level  congestion  management  obligations  to  terminal  operators  (without  defining 
specific mechanisms to be applied), for the terminals that currently rely only on users to 
return their unused capacity. 

• 

LT  UIOLI  should  remain  in  the  CMPs  as  a  safeguard  mechanism.  It  allows  the  NRAs  and 
TSOs to act upon cases of long-term network underutilization and provides a disincentive 
to market participants to use capacity hoarding to distort market operation. 

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1.  Introduction 

1.1  Policy background 

A well-functioning European gas market requires making efficient use of capacity at interconnection 
points (IPs), with a view to facilitating unimpeded gas exchanges across the borders of the Member 
States. To maximize efficiency, the transparent, non-discriminatory and market-based contracting 
of capacity should be combined with mechanisms and procedures that manage congestion, to free 
up and reallocate any booked but unused capacity and to avoid capacity hoarding. Depending on 
the situation at an IP, congestion may be physical or contractual. 

Article  16(3)  of  the  Gas  Regulation  (EC)  715/200910  required  Transmission  System  Operators 
(TSOs)  to  implement  non-discriminatory  and  transparent  congestion  management  procedures 
(CMPs) to facilitate cross-border exchanges. Annex I of the Regulation includes guidelines for the 
mechanisms to be applied at the IPs. The Annex was amended with the Commission Decision of 24 
August  201211,  which  constitutes  the  Congestion  Management  Procedure  Guidelines  (hereinafter 
referred to in this study as “CMP Guidelines” or “Guidelines”) currently in force. The CMP Guidelines 
focus specifically on IPs between Member States or within the same Member State and set out the 
procedures to be applied by the TSOs to manage congestion. The National Regulatory Authorities 
(NRAs) may also decide to apply the CMP Guidelines to entry/exit points from/to third countries. 
Offtakes  to  end-consumers  and  distribution  networks,  entries  from  LNG  terminals,  production 
facilities and connections with underground storages (UGSs) are not subject to the provisions of 
the CMP Guidelines. 

The CMP Guidelines continue to apply with the entry into force of the recast Gas Regulation (EU) 
2024/178912. Only minor revisions were made to the provisions of Guidelines, such as changing the 
frequency  of  ACER’s  Congestion  Report  from  annual  to  biannual.  Consequently,  the  same 
congestion management mechanisms that were put in place with the Guidelines 12 years ago are 
still applied, almost unchanged, more than a decade later13. 

The use of the gas networks, on the other hand, is undergoing significant changes. Multi-year legacy 
contracts that reserved capacity at many IPs in Europe are phasing out and are not being renewed, 
and network users, especially following the energy crisis, are shifting towards the use of shorter-
term capacity products. The weaponisation of gas by Russia, especially after the invasion of Ukraine, 
had a major impact on the gas flow patterns across Europe, with the South-to-North and West-to-
East  routes  prevailing  over  the  North-to-South  and East-to-West ones,  congesting  IPs  that  were 
rarely  used  until  then.  At  the  same  time,  decarbonization  of  the  energy  sector,  leads  to  the 
repurposing,  decommissioning,  or  dismantling  of  gas  assets,  which  can  impact  the  capacity 
availability in the gas networks. 

In this changing context, the Commission is considering the possible amendment of the existing 
CMP Guidelines. 

10 Regulation (EC) No 715/2009 of the European Parliament and of the Council of 13 July 2009 on conditions for access to the 

natural gas transmission networks (link) 

11 Commission Decision of 24 August 2012 on amending Annex I to Regulation (EC) No 715/2009 (link). 

12 Regulation (EU) 2024/1789 of the European Parliament and of the Council of 13 June 2024 on the internal markets for 

renewable gas, natural gas and hydrogen (link). 

13 Recital (95) of the recast Gas Regulation’s preamble implies that the CMP Guidelines should apply at IPs with third 

countries, unless an NRA applies for a (limited in time) derogation from applying the mechanisms in these IPs. 

13 

            
       
 
 
 
1.2  Objective of the study 

The general objective of this study is to support the Commission in assessing the extent to which 
the CMP Guidelines and other related regulations could be improved, in order to ensure an optimal 
use of the European gas infrastructure. 

Specifically, the study has the following objectives: 

•  Analysis of the congestion management procedures currently applied in the Member States 

and their implementation during the energy crisis. 

• 

• 

• 

Identification  of  information  needed  to  assess  the  efficient  use  of  gas  networks,  and  the 
availability and quality of this information. 

Identification  of  shortcomings  and  challenges  with  the  current  application  of  CMP,  which 
can be addressed with EU action, and in particular with the revision of the CMP Guidelines 
and other regulations. 

Formulation  of  recommendations  on  regulatory  improvements  that  address  the  barriers 
hindering  the  optimal  use  of  capacity  in  gas  infrastructure,  and  analysis  of  these 
interventions’ impact. 

1.3 

Implementation of the study 

The work carried out in the study was broken down into four the tasks, shown below. 

Figure 1: Overview of project tasks 

In Task 1, we reviewed the rules, procedures and regulatory approaches for managing congestion 
at natural gas infrastructure for all Member States with an obligation to apply CMPs14. The analysis 
focused on the regulatory documents providing for the CMPs in each Member State (network access 
rules, grid codes, contractual terms and conditions, etc.), and covered transmission network points, 
LNG terminals and UGSs.  

We identified network points that were congested in the past 3 gas years and collected data relating 
to  congestion  and  its  management.  Based  on  the  data  collection  exercise,  the  availability  and 
validity of CMP data were assessed. 

To complement the analysis carried out and information collected, we conducted interviews with 
NRAs and TSOs, to discuss the implementation of CMPs, the measures taken to optimize the use of 
the gas network, the challenges and lessons learned and any considerations for the future.  

In  Task  2,  we  analysed  the  data  collected  in  Task  1  for  the  congested  network  points.  The 
quantitative analysis focused on examining the nature of congestion (physical or contractual), the 
extent  to  which  demanded  capacity  was  not  met  at  the  capacity  auctions,  the  relevance  of  the 
capacity released through the application of CMPs to the actual use of the network point, and the 
level of congestion revenues due to the increased need for capacity. 

14 Excluding Cyprus that has no gas market, Malta and Sweden that have no IPs, and Luxemburg that holds a derogation. 

14 

            
       
 
 
 
 
To analyse the impact of decarbonization on the future congestion of the European gas system, we 
carried out a survey with key market stakeholders. The aim of this survey was to gather market 
intelligence information  about  any  challenges in the implementation  of  CMPs  due  to  the  planned 
evolution of the gas market and system. 

Drawing from the review of CMPs, the analysis of the congested network points and the interviews 
with  NRAs  and  TSOs,  we  identified  key  lessons  learned  and  challenges  with  the  management  of 
congestion. These findings were used to draw conclusions on the regulatory shortcomings for CMPs 
and the corresponding policy objectives that need to be addressed. 

Based on the shortcomings defined in the previous task, in Task 3 we identified potential regulatory 
interventions that can address the respective policy objectives. In some cases, alternative options 
addressing the same objective were considered. A survey with key stakeholders was carried out on 
the  design  and  application  of  CMPs,  to  collect  their  views  on  the  identified  challenges  and 
interventions, examining their relevance, importance and expected impact.  

The impact of the regulatory interventions to improve the procedures for managing congestion was 
assessed, under criteria that examine the areas of interest of the key impacted actors (NRAs, TSOs, 
network  users).  The  criteria  were  analysed  qualitatively,  taking  into  account  the  review  of  CMP 
rules, analysis of congested network points, inputs from the interviews with NRAs and TSOs and 
the results of the survey on the implementation of CMPs. 

In Task 4, we compared and prioritized the examined regulatory interventions based on a set of 
screening criteria (size and impact of the intervention, legal complexity, coherence with EU policy 
objectives, proportionality). Based on this analysis, specific recommendations were formulated on 
the  regulatory  interventions  to  be  taken  into  consideration  for  improving  the  design  and 
implementation of CMPs. 

A final workshop for the study was organized, to present the main findings and recommendations, 
and to discuss them with key market stakeholders. 

1.4  Structure of the study 

This document is organised into the following chapters: 

•  Chapter 1: Introduction presenting the general context, the objective of the study, and the 

work carried to implement it. 

•  Chapter  2:  Definition  of  physical  and  contractual  congestion  and  examination  of  the 

measures that can be applied to ensure the efficient operation of gas networks. 

•  Chapter 3: Overview of the CMPs applied by the EU Member States at the transmission 
network points, highlighting key alternative approaches followed and harmonization issues. 
Overview of the congestion procedures applied at LNG terminals and UGSs. Examination of 
the use of congestion revenues by the TSOs. Discussion on the impact of decarbonization 
on the congestion of gas systems. 

•  Chapter 4: Presentation of the results of the quantitative analysis carried out for the use 
of CMPs at congested network points, including an analysis of the availability and validity 
of data.  

•  Chapter  5:  Identification  of  the  main  areas  for  improvement  of  the  design  and 
implementation  of  CMPs,  analysis  of  the  regulatory shortcomings  and  challenges  in  each 
area  and  the  relevant  policy  objectives.  Identification  of  the  potential  regulatory 
interventions to address the policy objectives. 

•  Chapter 6: Results of the impact assessment of the identified regulatory interventions. 

15 

            
       
 
 
•  Chapter 7: Comparison and prioritization of the regulatory interventions. Formulation of 

specific recommendations for improving the design and implementation of CMPs. 

•  Annex I: Country briefs presenting the CMP procedures and rules applied in each Member 

State. 

•  Annex II: List of congested network points analysed in the study. 

•  Annex  III:  Case  studies  analysing  the  operation  and  use  of  CMPs  at  specific  network 

points. 

•  Annex IV: Results of the survey on the impact of decarbonization on congestion in the gas 

systems. 

•  Annex V: Results of the survey on the implementation of CMPs. 

16 

            
       
 
 
 
 
2.  Measures for efficient use of gas networks 

2.1  Efficient use of gas networks 

The TSOs are responsible for ensuring that the capacity of their gas networks is utilized as efficiently 
as possible, so that the network users’ requests for transporting gas through the network can be 
accommodated  to  the  largest  extent.  In  this  endeavour,  the  TSOs  may  have  to  face  network 
congestion  that  is  limiting  the capacity  that  can  be accessed  by  network  users  to  deliver  and/or 
withdraw gas. Congestion of the gas networks can be either physical or contractual. The definitions 
assigned to these two types of congestion vary, as shown in the table below. 

Table 1: Definitions of physical and contractual congestion 

Regulation (EU) 2024/1789 15 

ACER16 

Physical 
congestion 

“Situation where the level of demand for 
actual deliveries exceeds the technical 
capacity at a particular moment” 

“When gas flows reach the technical limit 
of the gas system” 

Contractual 
congestion 

“Situation where the level of firm capacity 
demand exceeds the technical capacity” 

“When the capacity of the gas 
transportation system is fully booked but 
remains partially unused, with actual gas 
flows below the technical limit of the gas 
system” 

The above definitions of physical congestion align, as they refer to the technical limits of the gas 
system, which cannot serve additional gas flows. On the other hand, the definitions of contractual 
congestion are conceptually different. Contractual congestion in Regulation (EU) 2024/1789 covers 
all the cases where demand for capacity exceeds the technical limits of the system. This may result 
in IPs that are fully booked and utilized being identified as contractually congested. ACER’s definition 
focuses only on the cases where capacity at the network points is fully booked but unused, which 
may for example be caused by capacity hoarding or suboptimal use of firm capacity products. This 
wording does not take into account the demand from market participants, for booked but unused 
firm capacity, which could result in capacity constraints in the market. 

Defining contractual congestion in a clear and concise way is critical for assessing the design and 
implementation of measures to manage congestion. The survey on the implementation of CMPs has 
indicated that the majority of stakeholders consider as most appropriate a definition of contractual 
congestion  that  identifies  network  points  where  firm  capacity  is  fully  booked,  this  capacity  is 
underutilized  and  there  is  interest  from  network  users  to  use  the  available  capacity17.  For  the 
purposes of this study, this definition is applied.   

The  nature  of  physical  and  contractual  congestion  is  different.  At  physically  congested  network 
points, the TSOs are called to tackle the structural technical constraints of the system. Although 
the  system  is  used,  at  least  at  times,  up  to  its  maximum  capacity,  market  needs  could  call  for 
additional  gas  flows  to  be  delivered  to  the  market.  On  the  other  hand,  contractual  congestion 

15 Regulation (EU) 2024/1789 of the European Parliament and of the Council of 13 June 2024 on the internal markets for 

renewable gas, natural gas and hydrogen (link). 

16 ACER - Congestion in the EU gas markets: have we reached a new normal? – 30 March 2024 (link). It is noted that in its 

Congestion Reports, ACER is using the definition of the CMP Guidelines (i.e. based on unmet demand of capacity at auctions) 
to determine which network points are identified as contractually congested. 

17 The results of the survey on the implementation of CMPs are presented in Annex V. 

17 

            
       
 
 
 
 
provides signals to an inefficient use of the network, by leaving booked firm capacity underutilized 
if this is not reallocated to other network users. The TSOs must take measures in order to mitigate 
both technical and commercial bottlenecks in their system: 

• 

Physical  congestion:  Careful  network  planning  is  required  to  assess  whether there is  a 
need for investments to lift technical bottlenecks. Non-infrastructure measures could also 
be employed to optimize gas flows. 

•  Contractual  congestion:  Market-based  measures  can  be  applied  by  the  TSOs  to  offer 
capacity that can be used if firm capacity is underutilized. Such measures are provided 
for in the Network Code on Capacity Allocation Mechanisms18 (CAM NC). Ex-post capacity 
release through the activation of CMPs can also be used. 

These measures work in a complementary way to mitigate congestion and to optimize the use of 
gas  networks.  There  can  be  cases  of  network  points  being  both  physically  and  contractually 
congested at different periods of time, depending on how capacity has been booked by the network 
users.  

The figure below provides an overview of the measures applied to ensure the efficient use of the 
gas networks. 

Figure 2: Measures for efficient use of gas networks 

The same considerations for physical and contractual congestion also apply to LNG terminals and 
underground  gas  storages.  Market-based  measures  and  mechanisms  to  manage  congestion  are 
often used to optimize capacity utilization at these gas facilities. 

2.2  Network planning 

During network planning, TSOs assess whether the technical limitations and potential bottlenecks 
at  their  transmission  system  can  justify  further  investment.  Utilization  of  the  network  points  is 
usually monitored ex-ante, to identify cases with high risk of physical congestion, that merit further 
examination.  Such  cases  should  be  assessed  as  part  of  the  preparation  of  the  operator’s 
development plan, to identify the necessary investments, if any.  

Incremental capacity was introduced in the CAM NC as a harmonized mechanism (inspired by the 
open  season  mechanisms)  to  serve  additional  market  needs  and  implicitly  address  physical 
congestion19. The mechanism sought to incorporate future market needs to justify development of 

18 Commission Regulation (EU) 2017/459 establishing a network code on capacity allocation mechanisms in gas transmission 

systems (link). 

19 It should be noted that following a judgement by the Court of Justice of the European Union in 2022 (link), Chapter V of 

CAM NC on incremental capacity was annulled, and there is currently not a framework governing the  cross-border 
incremental capacity projects, notably on the joint decision to approve/impose the on TSOs the final investment decision. 

18 

            
       
 
 
 
 
new  gas  infrastructure,  including  interventions  to  lift  bottlenecks.  However,  the  current  market 
conditions, such as the shift towards short-term gas supplies and exchanges, including spot imports 
of LNG into the EU, do not favour long-term commitments of network users. 

Planning for new investments to enhance capacity should take into account the changes in the gas 
sector resulting from decarbonization. Phasing out of natural gas and the subsequent decrease of 
gas flows through the network, could result in the stranding of new assets. At the same time, the 
potential downsizing of the gas network, due to repurposing for hydrogen, could raise security of 
supply concerns and increase the occurrence of physical congestion. The recast Gas Directive (EU) 
2024/1788 has introduced new requirements to improve network planning, provided for in Article 
55, including the mandatory preparation of development plans by the TSOs, joint scenario building 
and cross-sectoral integration.    

2.3  Operational optimization 

Depending  on  the  transmission  system’s  architecture  and  location,  a  TSO  may  apply  non-
infrastructure solutions to overcome physical constraints, without necessarily the need for additional 
investments. As one such measure, the rerouting of physical gas flows through other network points 
(indirect routes) could bypass the congested point. For example, in Germany, as an instrument to 
overcome potential bottlenecks after the market merger of GASPOOL and NetConnect to THE, the 
TSOs have the possibility to consider transiting third-party networks to deliver gas from one system 
to the other20. 

2.4  Marketing of capacity 

The CAM NC offers a set of market-based instruments for offering capacity at the IPs that can be 
applied by the TSOs to optimize the use of capacity.  

The TSOs must coordinate in order to maximize the offer of firm bundled capacity, giving priority 
to the IPs that are contractually congested. This optimization of the capacity offered at both sides 
of an IP may increase the available firm capacity. Nevertheless, there are cases where non-technical 
constraints may hinder the maximization of capacity. In particular, legacy contracts that reserve 
capacity on a long-term basis can limit the possibility to bundle capacity and result in interruptible 
capacity being offered at the other side of the IP. Although such legacy contracts are phasing out, 
they still exist in several Member States21. To limit the impact of legacy contracts on bundling of 
capacity, the TSOs offer, in accordance with CAM NC, a capacity conversion service to holders of 
unbundled capacity contracts at their IPs. 

Capacity of interruptible quality must be made available by TSOs, if firm capacity at an IP is fully 
booked.  This  allows  additional  network  users  to  access  contractually  congested  IPs  which  are 
underutilized,  but  cannot  address  physically  congested  points,  where  all  booked  firm  capacity  is 
nominated. The TSOs can decide whether interruptible capacity of one day or longer will be offered, 
based on the needs of the network users and the utilization of the IP. An over-nomination procedure, 
activated  by  the  TSO,  can  also  make  within-day  interruptible  capacity  available,  maximizing  the 
possibility of the network users to take advantage of any unnominated firm capacity.  

The offering of competing capacity between network points allows the operator to better manage 
the system and offer firm capacity despite technical limitations. Although such products do not lift 

20 Annual Monitoring Report pursuant to KAP+ (link). 

21 The stakeholders’ responses to the survey on the implementation of CMPs (Annex V) validates the existence of legacy 

contracts in several Member States. 

19 

            
       
 
 
 
bottlenecks,  they  can  enable  additional  firm  capacity  to  be  available  at  certain  IPs,  instead  of 
offering increased interruptible capacity.  

Network users are given the possibility to trade (sell or sublease) their capacity rights at secondary 
markets.  The  operational  modalities  of  the  secondary  capacity  market  are  set  by  the  national 
network access rules and regulations of each Member State. Depending on the national framework, 
transactions may be bilateral between network users or take place on the booking platforms or the 
TSO’s electronic platform. Besides IPs, the TSOs usually allow trading of capacity at other network 
points as well. It has been observed by TSOs that the interest for secondary trading of capacity 
rights can be high during periods of congestion.  

Any regulatory interventions to address potential shortcomings and improve these market measures 
are  part  of  the  revision  process  of  the  CAM  NC  and  are  thus  not  examined  in  this  study. 
Nevertheless,  the  relevance  of  market-based  measures  in  managing  congestion,  and  their 
complementarity to CMPs is taken into consideration. 

2.5  Role of CMPs in the efficient use of gas networks 

In principle, the CMPs are activated at congested network points to make capacity available in case 
the market-based measures (e.g., the offering of interruptible capacity or secondary trading) are 
not sufficient to ensure the efficient use of the network. The CMPs have been designed to address 
contractual congestion, by releasing firm capacity, which is booked but unused, for example due to 
inefficient contracting of firm capacity products or capacity hoarding. At physically congested points, 
where the system is actually used at its technical constraints, the use of CMPs can provide additional 
network users with the possibility to access part of the capacity but cannot resolve the congestion 
itself. The application of CMPs to release capacity is often considered by the TSO and the NRA as a 
fall-back measure because the mechanisms affect the firmness of the provided transmission service. 

The  CMP  Guidelines  set  out  the  procedures  to  be  applied  by  the  TSOs  to  manage  contractual 
congestion on IPs between Member States or within the same Member State (Table 2). Currently 
the NRAs can decide to apply the CMPs included in the Guidelines to cross-border points with third 
countries (after August 2026 all network codes and guidelines will have to apply at all IPs including 
those with third countries22). Although not subject to the provisions of the Guidelines, CMPs may 
also  be  used  at  other  internal  network  points,  such  as  interfaces  with  LNG  terminals  and 
underground gas storages. 

Table 2: Congestion management procedures provided for in the CMP Guidelines 

CMP 

Overview of the mechanism 

Comments 

Capacity 
oversubscription and 
buy-back (OS+BB) 

The TSO can opt to offer additional firm capacity at 
the IP than is technically available 
(oversubscription). The additional capacity is 
marketed and charged as regular firm capacity.   

The TSO must buy back the additional capacity 
from network users if required due to physical 
congestion. 

The NRA must decide 
whether FDA UIOLI shall 
apply at the congested IPs. 

OS+BB is considered in the 
Guidelines as the basic 
instrument to prevent 
contractual congestion, 

22 Recital (95) of recast Gas Regulation (EU) 2024/1789. 

20 

            
       
 
 
 
Firm Day Ahead Use- 
it-or-Lose-it 24 (FDA 
UIOLI) 

The Guidelines require NRAs to consider using FDA 
UIOLI at IP sides identified as congested in the 
annual ACER Congestion Report.  

with FDA UIOLI meant as a 
fall-back measure23. 

The mechanism sets a limitation to the upward 
and downward firm renominations of network 
users based on their booked capacity. 
Renominations beyond the limits are treated as 
interruptible. 

Surrender of 
capacity 

The TSO must accept the surrender of firm 
capacity rights contracted to network users (before 
the auction date of the respective product), in 
order to offer it back to the market. Capacity 
rights of day-ahead or intra-day duration cannot 
be surrendered. 

The user surrendering capacity retains its rights 
and obligations until the capacity is reallocated. 

The mechanism must be 
applied by all Member 
States.  

It allows the voluntary 
release of firm capacity 
that was booked but not 
used. 

Long-term Use-it-or-
Lose-it (LT UIOLI) 

The TSO can withdraw capacity contracted by a 
network user that is systematically underutilized 
(under specific criteria defined in the Guidelines). 

The mechanism must be 
applied by all Member 
States.  

The user having its capacity withdrawn retains its 
rights and obligations until the capacity is 
reallocated. 

It aims to address cases of 
capacity hoarding. 

The CMPs included in the Guidelines were designed in the early 2010s, when the vast majority of 
capacity  contracts  had  multi-year  durations  and  were  held  by  the  gas  markets’  incumbents.  In 
recent years, especially at IPs where legacy contracts ended, there has been a shift from long-term 
to  short-term  booking  of  capacity.  Network  users  tend  to  buy  more  monthly  and  daily  capacity 
products,  to  align  as  optimally  as  possible,  their  bookings  and  gas  deliveries25.  This  trend  has 
affected the role of CMPs  in the overall efficient use of gas networks and the cases where these 
have to be activated. Multi-year capacity contracts are phasing out, reducing the risk of capacity 
hoarding, while the increased use of short-term products is reducing the need for network users to 
surrender  their  capacity.  Nevertheless,  the  CMPs  continue  to  be  used  to  prevent  contractual 
congestion, often as a backup to market measures.  

24 Firm Day Ahead Use- It-Or-Lose-It (FDA UIOLI) may also be referred to as Short-Term Use-It-Or-Lose-It (ST UIOLI). In 

this study the term FDA UIOLI is used.  

23 Commission Staff Working Document (July 2014): Guidance on best practices for congestion management procedures in 

natural gas transmission networks (link) 

25 As shown by the responses to the survey on the implementation of CMPs (Annex V), network users in several Member 

States prefer the use of monthly or shorter-term capacity products. 

21 

            
       
 
 
 
 
3.  Mapping of CMPs in EU Member States 

3.1  Application of the CMP Guidelines in the EU 

After the entry into force of the CMP Guidelines in 2012, rules and regulations applying them were 
put  in  place  in  the  Member  States.  Since  their  initial  establishment,  no  significant  changes  have 
been observed in the CMPs applied by each Member State. The Table below maps the CMPs applied 
in each Member State. 

Table 3: CMPs applied by each Member State 

MS 

OS+BB 

FDA UIOLI 

Surrender 

LT UIOLI 

Austria 

Belgium 
Bulgaria26 

Croatia 

Cyprus 

Czech Republic 

Denmark 

Estonia 
Finland 27 

France 
Germany 28 
Greece29 

Hungary 

Ireland 

Italy 

Latvia 

Lithuania 

Luxembourg 

Malta 

Netherlands 

Poland 

Portugal 
Romania30 

Slovakia 

Slovenia 

Spain 

Sweden 

 
 
 

 
 
 

 

 
 
 

 
 

 

 

 

 
 
 

 

 
 

 
 
 
 

Not applicable (No gas market) 

 

 
 
 

Implicit allocation of capacity  

 
 
 

 

 
 
 
 
 
 
 
 

Derogation under Article 49 of Gas Directive 

Not applicable (No IPs) 
 

 

 

 

 
 
 
 
 

Not applicable (No IPs) 

 
 
 
 

 
 
 

 
 
 
 
 
 
 
 

 

 

 
 
 
 
 

N.B.: : Applied CMP   : Provisions for an OS+BB mechanism in place but no additional capacity offered in the past 3 gas 
years 

26 The OS+BB mechanism applies at the IPs of Bulgartransgaz’ national transmission system. The FDA-UIOLI mechanism 

applies at the IP of the interconnector IGB. 

27 Capacity at the IP Balticconnector is allocated implicitly, and it appears that the CMPs are not in place.  

28 TSOs in Germany also offered additional capacity through oversubscription, but not as a CMP mechanism. For this reason, 

they are not included in the list of Member States applying OS+BB. 

29 The OS+BB mechanism applies at the IPs of DESFA’s national transmission system. The FDA-UIOLI mechanism applies at 

the IPs of the interconnectors TAP and IGB. 

30 According to ENTSOG’s 2023 monitoring report for congestion management, implementation of CMPs in Romania was 

expected in 2023. Review of Transgaz’ network code indicates that neither OS+BB nor FDA UIOLI is in place yet.  

22 

            
       
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
The  surrender  and  LT  UIOLI  mechanisms  are  in  place  in  all  the  Member  States  that  have  the 
obligation to apply the CMPs. 18 Member States have established rules for OS+BB, however only 6 
(France,  Greece,  the  Netherlands,  Portugal,  Slovakia  and  Spain)  have  made  available  additional 
capacity through oversubscription over the past 3 gas years. The FDA UIOLI mechanism is being 
applied in 10 Member States (Greece and Bulgaria apply the mechanism at IPs of interconnectors 
and not in their national transmission systems). In these, 5 TSOs (in Croatia, the Czech Republic, 
Hungary,  Poland  and  Slovenia)  include  in  their  network  access  regulations  the  possibility  of  an 
OS+BB mechanism, but do not apply it in practice. 

The OS+BB mechanism has been used in Germany since October 2021. Its application, however, 
does not aim to manage congestion, but is used as one of the mechanisms to make additional firm 
capacity available after the merger of GASPOOL and NCG into a single market area, the Trading 
Hub Europe (THE). Due to its different scope, this mechanism is not included in Table 3. 

Not all Member States apply the CMPs at the same type of network points. The figure below provides 
an overview of the types of network points at which each CMP applies.  

Figure 3: Application of CMPs at different types of network points 31 

OS+BB 

FDA UIOLI 

Surrender of capacity 

LT UIOLI 

Although the OS+BB mechanism is, in some Member States, applicable to different types of network 
points, including IPs with third-countries, in practice no TSO has activated the mechanism at any 
network point other than IPs shared with neighbouring EU gas systems. In some Member States 
the  FDA  UIOLI  mechanism  is  activated  only  on  congested  IPs,  while  in  others  (Austria,  Croatia, 
Czech Republic, Germany) the renomination restrictions apply at all IPs regardless of whether they 
have been identified as congested or not. In most Member States the surrender and LT UIOLI apply 
at the same type of network points. 

31 Ireland is the only Member State where the CMPs apply only at IPs with a non-EU country (UK). 

23 

            
       
 
 
 
 
 
 
 
All the EU NRAs opted for a derogation from paragraphs 1–6 of Article 14 of Regulation 2022/257632. 
The  NRAs  considered  that  the  existing  CMP  mechanisms  and  market  measures  in  place  (which 
allowed them to meet the derogation criteria stipulated in Article 14(7)) were sufficient to manage 
congestion and did not consider that the monthly UIOLI mechanism of this Regulation would add 
further value. 

3.2  Rules and procedures to manage congestion at network points 

3.2.1  Capacity oversubscription and buy-back 

Many Member States have put in place capacity oversubscription and buy-back mechanisms, which 
allow TSOs to provide additional firm capacity at contractually congested IPs. Use of the mechanism 
is  not  meaningful  in  the  case  of  physical  congestion,  as  the  risk  of  the  TSO  having  to  buy  back 
capacity is high. 

Typically, additional capacity can be sold at a network point only after all surrendered and withdrawn 
(due to LT UIOLI) capacity has been reallocated. Any additional capacity must be sold in the primary 
market without distinction from the available firm capacity, i.e. network users cannot explicitly buy 
additional  capacity.  Usually,  the  additional  capacity  is  included  exclusively  in  daily  firm  capacity 
products. Nevertheless, in a few Member States, longer-term products can also be oversubscribed; 
in the Netherlands, Gasunie may sell additional capacity at monthly, quarterly and yearly auctions, 
while  in  Bulgaria,  Bulgartransgaz  can  offer  monthly  available  capacity  together  with  additional 
capacity. 

Although additional capacity is offered together with available firm capacity, TSOs must notify the 
network  users  about  the  trigger  of  the  oversubscription  mechanism,  indicating  the  amount  of 
additional  capacity  that  is  being  auctioned.  This  is  necessary  to  ensure  that  network  users  are 
informed  of  the  possibility  that  the  TSO  may  trigger  a  buy-back  mechanism  for  the  additional 
capacity sold. Some TSOs publish the daily additional capacity at their websites, while others flag, 
in the notices of the booking platforms, the auctions containing oversubscribed capacity. 

Oversubscription  is  activated,  in  most  Member  States  at  the  TSO’s  initiative,  after  assessing 
statistical data and carrying out risk analysis that determines the amount of additional capacity to 
be  offered.  In  a  few  cases  the  mechanism  is  triggered  following  a  request  from  network  users 
(Denmark, Estonia, Latvia, Lithuania). Over the past 3 gas years, only TSOs in France, Greece, the 
Netherlands,  Portugal,  Slovakia  and  Spain  have  activated  the  oversubscription  mechanism  and 
marketed additional capacity at the capacity auctions of contractually congested IPs. 

The TSOs must establish the methodology to estimate the amount of additional capacity, including 
the approaches followed to quantify the risk, estimate the threshold above which to activate the 
mechanism  and  calculate  the  capacity  to  be offered.  This  methodology is  often  approved  by  the 
NRA. The methodological approaches of only a few TSOs, such as Enagás, REN, Teréga and DESFA, 
are publicly available. 

In case the technical capacity at an IP, at which additional capacity has been booked, is not sufficient 
to accommodate the nominations submitted by the network users, the TSO can trigger the buy-
back  mechanism.  Before  doing  so,  the  TSO  should  first  consider  measures  of  technical  (e.g., 
rerouting of gas flows) and commercial (e.g., interruption of nominations for interruptible capacity, 
management  of  the  operational  balancing  account)  nature  to  manage  the  congestion.  If  these 
measures are not sufficient, the TSO notifies the network users that have contracted firm capacity 

32 Council Regulation (EU) 2022/2576 enhancing solidarity through better coordination of gas purchases, reliable price 

benchmarks and exchanges of gas across borders (link). 

24 

            
       
 
 
 
at the IP on that day, that the buy-back procedure has been activated. The modality and the lead 
time  for  notifying  the  users  differ  among  TSOs,  depending  on  their  internal  procedures  and 
electronic management systems. 

The  procedures  followed  by  the  TSOs  to  buy  back  capacity  are  market-based.  The  different 
mechanisms applied by the TSOs include: 

  Auctions at a booking platform with a “uniform price” algorithm, following similar principles 

to the daily capacity auctions foreseen in CAM NC. 

  Secondary trading of capacity with the TSO acting as the buyer. 

 

Tenders  for  capacity,  with  bids  submitted  by  the  network  users  either  via  the  TSO’s 
electronic platform or via electronic messages. 

Regardless  of  the  mechanism  applied  for  network  users  to  sell  their  additional  capacity,  the 
responses  of  network  users  interested  in  selling  back  their  capacity  must  include  the  amount  of 
capacity returned and the asking price. The TSO selects the bids following a least price merit order.  
Several TSOs set a maximum on the users’ asking price, which is usually linked to the tariff of the 
daily firm capacity product applied at the IP. These caps are approved by the NRAs, as part of the 
regulatory document in which the buy-back mechanism is determined. Table 4 presents the price 
caps applied in different Member States. 

Table 4: Maximum buy-back price allowed in different Member States 

Member State 

Maximum allowed buy-back price 

Czech Republic 

1.5x multiple of the daily firm capacity product 

Estonia, Latvia, Lithuania 

3x multiple of the within-day firm capacity product 

France 

Greece 

Poland 

Portugal 

Spain 

Average  of  the  clearing  prices  of  the  quarterly, 
monthly,  and  day  ahead  auction  weighted  by  the 
booked quantities during these auctions, plus 25% 

1.5x multiple of the daily firm capacity product 

10x multiple of the daily firm capacity product 

1.2x multiple of the daily firm capacity product 

1.25x multiple of the daily firm capacity product 

In  case  the  TSO  still  cannot  meet  all  requested  nominations,  despite  activating  the  buy-back 
mechanism, then the TSO proceeds with a pro-rata restriction of the use of firm capacity products 
by the network users holding capacity, or having submitted nominations, for the specific gas day at 
the IP. 

The actual use of the buy-back procedure and market mechanism has been very limited, thus their 
functionality and efficiency have not been tested in practice. 

3.2.2  Firm day-ahead use-it-or-lose-it 

Some Member States trigger the FDA UIOLI mechanism in case an IP is identified as congested, on 
the basis of the criteria included in the CMP Guidelines. Others (Austria, Czech Republic, Croatia, 

25 

            
       
 
 
Germany) have opted to apply the mechanism at all IPs regardless of whether they are congested 
or not. Most TSOs apply the renomination restrictions exactly as foreseen in the CMP Guidelines. 
As  shown  in  Figure  4,  the  network  users  are  allowed  to  renominate  upwards  up  to  90%  and 
downwards up to 10% of their booked capacity, if their initial nomination was between 80% and 
20% of the booked capacity. For nominations exceeding 80%, upward renomination is permitted 
for  half  of  the  non-nominated  range.  Conversely,  for  nominations  below  20%,  downward 
renomination is allowed for half of the nominated range.  

Figure 4: Renomination restrictions of FDA UIOLI 

In Italy the approach followed for activating the FDA UIOLI is relatively different from that in other 
Member States. Instead of continuously applying the mechanism to restrict renominations, the FDA 
UIOLI  is  activated  at  the  designated  IPs  during  all  the  days  of  a  month,  only  if  the  demanded 
capacity in that month exceeds the offered capacity, or if the whole capacity of the IP has been 
booked in the previous annual and quarterly capacity auctions. When the mechanism is triggered, 
the TSO withdraws the booked capacity of the network users beyond the restrictions and offers it 
as firm capacity in the next daily and within-day capacity auctions. 

These restrictions do not apply to network users that held less than 10% of the average technical 
capacity at the IP. The period for which the average capacity is calculated differs among the TSOs. 
Some consider the previous gas year (Czech Republic), the calendar year (Slovenia) or past 365 
days (Austria). 

The network users are allowed to renominate gas volumes beyond the upward restrictions, however, 
this part of the renomination is treated as interruptible capacity and is interrupted first in case of 
physical congestion. Some Member States limit the downward renominations, for example, in Italy 
the renominations below the allowed threshold are rejected. 

Some TSOs inform their network users of the day-ahead renomination restrictions, based on the 
booked capacities of each user. This information is usually provided by the TSO after the closure of 
the nomination procedure and before the first renomination procedure commences.  

Some Member States have in place explicit rules regarding the impact of releasing capacity through 
FDA  UIOLI  on  the  network  charges  paid  by  the  affected  network  user.  For  example,  in  Austria, 
Croatia and Hungary the user is required to pay the firm capacity tariffs without any discount, even 
though part of its firm capacity rights were interrupted. 

3.2.3  Surrender of capacity 

In  accordance  with  the  CMP  Guidelines,  TSOs  must  accept  surrender  of  capacity  contracts  from 
network users, except for daily or within-day durations. Nevertheless, a few TSOs (e.g., in Italy, 
Estonia,  Latvia,  Lithuania)  also  accept  the  surrender  of  daily  firm  capacity  products.  Some  TSOs 
allow network users to surrender firm capacity regardless of whether there is available capacity at 

26 

            
       
 
 
 
the specific network point, while others accept surrender applications only for the network points 
that are congested (e.g., in Ireland). In any case, however, the surrendered capacity is allocated 
to users only after the remaining available firm capacity at the network point has been booked.  

The TSOs often give network users the flexibility to surrender their booked firm capacity products 
by  splitting  them  into  products  with  shorter-term  duration  of  the  same  quality.  For  example,  in 
Denmark, any surrendered annual firm capacity that is not sold is then re-marketed sequentially as 
quarterly-monthly-daily firm capacity. In Germany, network users are allowed to surrender capacity 
for  any  day  or  days  and  for  any  amount  of  capacity  up  to  that  originally  booked.  In  Portugal,  
surrendered  capacity  is  sold  as  shorter-term  products  (e.g.,  quarterly  capacity  is  marketed  as 
monthly and daily capacity). 

In case more than one network user surrenders capacity at the same network point, a first-come 
first-served principle is followed, with the earliest surrendered capacity being marketed first. Some 
TSOs  also  cover  the  event  of  surrender  requests  being  submitted  simultaneously  (or  within  the 
same day), in which case a pro-rata mechanism applies. 

The network users are not allowed to sell surrendered capacity to the secondary market and are 
required to withdraw any relevant offers they have already put on the market (or such capacity is 
not accepted by the TSO). This is not a restriction deriving from the CMP Guidelines. Instead, it is 
a common practice among TSOs, to avoid the same capacity being sold twice from the TSO and the 
user. Only after the TSO has offered the surrendered capacity in the primary market, and this has 
been returned to the user, can the latter place it in the secondary market.     

The treatment of the revenues resulting from the re-marketing of the surrendered capacity differs 
among the TSOs. For example, in Austria and Hungary, the user has no right to any auction premia 
from the reallocation of its surrendered capacity. In France and Spain, the user must pay the TSO 
if there is a deficit in the network charges resulting from the reallocation of capacity to other users. 
In Germany and Poland, the user surrendering capacity must still pay any auction premia from their 
initial  capacity  booking.  In  Belgium,  the  TSO  pays  to  the  network  user  any  auction  premium 
generated when selling the surrendered capacity, while at the same time it charges the user with 
an administrative fee. 

3.2.4 

Long-term use-it-or-lose-it 

The TSOs are required to monitor the utilization of long-term booked capacity and to identify cases 
in which it is being systematically underutilized. Capacity with duration of more than one year (or 
capacity booked for recurring quarters for at least two years) is monitored. In some Member States, 
the TSO is required to report to the NRA, analysing the use of capacity by the network users. These 
reports are submitted either annually or biannually (covering the periods from 1st October to 31st 
March and 1st April to 30th September). 

When monitoring the use of capacity, the TSOs take into consideration the underutilization threshold 
of 80% of booked capacity, as foreseen in the CMP Guidelines (systematically underutilized IP). The 
criteria, however, for triggering the LT UIOLI mechanism, and for examining the release of long-
term capacity booked by a network user, are implemented in varying ways by the TSOs:   

•  Some TSOs trigger the mechanism in case the underutilization criterion applies, and one or 
more network users seek to contract firm capacity at the point, which cannot be fulfilled by 
the TSO. 

•  Other  TSOs  trigger  the  mechanism  if  the  monitoring  of  capacity  use  indicates  that  the 

network point is systematically underutilized.  

27 

            
       
 
 
Consequently, in the first case the TSO acts only after network users’ requests for capacity, whereas 
in the second case the TSO acts on its own initiative, based on its monitoring of the network point’s 
utilization.  This  different  interpretation  of  the  triggering  conditions  for  LT  UIOLI  resulted  in 
unharmonized efforts to release capacity at the VIP Pirineos, as discussed in Section 3.3. 

Before proceeding to withdraw capacity, the TSO must first investigate whether the network user 
sought to sell the underutilized capacity at the secondary market, and/or provide to the user the 
possibility to justify the low utilization. According to the CMP Guidelines, capacity should have been 
offered at the secondary market under “reasonable conditions”. Some TSOs define this term in their 
access  rules  or  terms  and  conditions.  For  example,  in  the  Czech  Republic  and  in  Italy  the  price 
offered by the user at the secondary market must not exceed the reserve price offered by the TSO 
in the primary market. In Spain the “reasonable conditions” are met, if the price offered by the user 
at the secondary market is equal to or lower than the maximum value between the tariff at the time 
that the  capacity  is  offered,  the price on the  secondary  market,  and  the  price  at  which  the user 
initially booked the capacity.  

The decision for the release of capacity through the LT UIOLI mechanism may be taken either by 
the  TSO  or  the  NRA  (Table  5).  In  many  Member  States,  the  NRA  decides  on  the  withdrawal  of 
underutilized  capacity,  on  the  basis  of  information  provided  by  the  TSO  and  often  its 
recommendation.  Alternatively, the TSO decides if the mechanism should be activated, based on 
the  criteria  defined  in  the  national  regulations,  while  the  NRA  has  a  monitoring  role.  In  some 
mechanisms it is also possible for either the NRA or TSO to decide on the withdrawal of capacity, 
based on the trigger conditions. 

Table 5: Role of the NRA and TSO in the LT UIOLI mechanism 

Member States 

NRA decision for capacity 
withdrawal33  

Belgium, Bulgaria, Czech Republic, Denmark, 
France, Germany, Hungary, Ireland, Poland, 
Romania, Slovakia, Slovenia 

Capacity withdrawal by the TSO 

Austria, Hungary, Estonia, Greece, Italy, Latvia, 
Lithuania, Portugal, Spain 

The capacity released through the LT UIOLI mechanism is offered by the TSO in the firm capacity 
auctions  and  is  sold  only  after  the  available  firm  capacity  and  any  surrendered  capacity  at  the 
network point have been allocated. Depending on the rules in place, once the mechanism has been 
triggered,  or  after  the  released  capacity  has  been  put  on  the  primary  market  by  the  TSO,  the 
network user no longer has the right to sell it at the secondary market.  

Each TSO follows its own procedure for triggering the LT UIOLI mechanism and examining whether 
capacity should be withdrawn. Nevertheless, some elements are common for all TSOs, such as the 
notification of shippers to justify the underutilization, the examination of whether capacity was put 
on the secondary market and the final decision of whether to release capacity or not. An example 
of such a process, applied by Fluxys in Belgium, is presented in the figure below. 

33 Includes also cases where the TSO may also withdraw capacity on its own initiative, if certain conditions are met. 

28 

            
       
 
 
 
 
Figure 5: Example of process for releasing capacity through the LT UIOLI34 

The  capacity  that  is  released  and  offered  back  to  the  market  should  be  commensurate  with  the 
underutilized part of the capacity, and the requests of other users for firm capacity. In some Member 
States, the capacity up to the 80% threshold is withdrawn, sometimes also putting a cap to the 
maximum  capacity  that  can  be  released35.  In  other  Member  States,  the  capacity  released 
corresponds to that requested by network users, which resulted in triggering the mechanism. The 
period  for  which  capacity  is  withdrawn  may  also  be  specified,  for  example,  in  Belgium  capacity 
should be withdrawn for at least 2 months, in Bulgaria the maximum withdrawal period is 1 year, 
in the Netherlands for 2 years, and in Spain for the subsequent gas year. 

Some TSOs have in place specific rules for the payments concerning the released capacity. In the 
Czech Republic, France, Portugal and Spain, the network user having its capacity withdrawn must 
cover any difference in the price between the reallocated and initially booked capacity. In Hungary, 
the network user does not receive any premia resulting from reallocation of its released capacity. 
In  Belgium  the  network  user  is  compensated  for  the  reallocated  capacity  at  the  regulated  tariff, 
minus an administrative fee. 

34 Source: Fluxys Access Code for Transmission, Attachment E (link) 

35 For example, in the Czech Republic no more than 50% of the booked capacity can be released. 

29 

            
       
 
 
 
 
3.3  Harmonization of CMPs by adjacent TSOs 

3.3.1  Application of OS+BB and FDA UIOLI at the sides of an IP 

The use of the OS+BB and FDA UIOLI mechanisms at the two sides of an IP could potentially result 
in  misalignment  in  the  use  of  capacity  by  the  network  users  of  the  adjacent  systems.  This 
particularly relates to the ability to renominate downwards, which is unconstrained when OS+BB 
applies, but is limited by FDA UIOLI. If the buy-back mechanism is activated and nomination of a 
user  is  decreased below  the  FDA  UIOLI  restriction,  then  application  of  the lesser  rule during the 
matching process will result in the TSO applying the FDA UIOLI not being able to practically make 
use of the 10% constraint (Figure 6). On the other hand, the upward renomination restrictions of 
FDA UIOLI are not affected, as following the application of the lesser rule the renomination can be 
limited to the upward limit. 

Figure 6: Example of renomination restrictions if both OS+BB and FDA UIOLI apply  

The cross-border IPs where potential issues could have actually occurred are limited, due to the 
way that the TSOs are using the two mechanisms in practice. Although many NRAs have set up 
rules  for  oversubscription,  only  a  few  TSOs  are  actually  offering  additional  capacity.  Where  the 
national regulations include both mechanisms, the FDA UIOLI applies at congested IPs. The map 
below (Figure 7) presents the application of the two mechanisms across the EU.   

Figure 7: Application of OS+BB and FDA UIOLI by the Member States 

Out of the Member States applying the OS+BB: 

30 

            
       
 
 
 
 
•  Spain and Portugal share IPs only with Member States applying the same mechanism. 

•  GRTGaz  in  France  does  not  offer  additional  capacity  at  its  interconnection  point  with 

Germany (where FDA-UIOLI is applied). 

•  Gasunie in the Netherlands offers additional capacity at the VIPs with Germany, however 
no harmonization issues were identified through the analysis carried out in this study. 

•  DESFA in Greece offers additional capacity only at the IP with Bulgartransgaz. 

• 

Eustream  in  Slovakia  offered  additional  capacity  at  the  IPs  with  Austria  and  the  Czech 
Republic until the end of 2021.  

The responses of stakeholders in the survey on the implementation of CMPs (described in Annex V) 
have highlighted that the use of different mechanisms to manage congestion at the two sides of an 
IP can have adverse effects on the operation of the IP. Although this is the case in principle, the 
analysis of the congested network points, interviews with the NRAS and TSOs and inputs provided 
in the survey have not provided evidence indicating specific cross-border IPs where the application 
of different measures has caused in the past, or is currently causing, undue restrictions in the use 
of booked capacity. 

The interviews with stakeholders have not indicated any issues or constraints with the application 
of CMPs at the borders with third-countries. If a TSO applies a mechanism in such cases, it appears 
that it does not coordinate with the adjacent non-EU TSO. 

3.3.2 

Joint application of the OS+BB mechanism 

The  CMP  Guidelines  require  NRAs  to  coordinate  before  implementing  the  OS+BB  mechanism.  A 
procedure for joint set up of the mechanism is publicly available for VIP Pirineos between France 
and Spain (Figure 8) and for VIP Iberico between Spain and Portugal, which are the only bordering 
Member States offering additional capacity through oversubscription over the past few years.  

Figure 8: Joint OS+BB process of Enagás and Teréga36 

36 Source: Enagás, Teréga – Procedure for the implementation of the oversubscription and buy-back scheme (link) 

31 

            
       
 
 
 
 
This coordination covers the full span of the mechanism, including the methodology and approach 
for  offering  additional  capacity,  the  buy-back  procedure  and  pricing  and  the  split  of  costs  and 
revenues between the TSOs. As a result of this joint procedure, the TSOs are in a position to offer 
additional capacity as bundled firm, and to have a coordinated buy-back procedure. 

3.3.3  Harmonization of LT UIOLI rules 

The provisions of the CMP Guidelines relating to the LT UIOLI allow flexibility and alternatives on 
how the mechanism will be implemented in practice. As a result, key elements of the mechanism, 
such  as  the  triggering  conditions  and  the  amount  of  capacity  to  be  released  have  been  applied 
differently in Member States.  

The  lack  of  a  consistent  approach  in  the  design  of  the  mechanism  resulted  in  issues  with  the 
activation  of  the  mechanism  at  VIP  Pirineos.  Enagás  and  Teréga  applied  the  mechanism  with 
different approaches at the two sides of the IP, with only Teréga examining whether there is unmet 
demand  for  long-term  firm  capacity  (Table  6).  The  application  of  different  activation  conditions 
resulted  in  Enagás  not  being  able  to  release  capacity  at  its  side  of  the  VIP,  as  Teréga  had  not 
received a request from another network user that could not be satisfied. 

Table 6: Different approaches of LT UIOLI mechanism at VIP Pirineos 

Activation 
conditions 

Spanish side of VIP Pirineos 
(Enagás) 

French side of VIP Pirineos (Teréga) 

In both periods between 1 April and 30 
September, and between 1 October and 
31 March: 

•  The ratio of average used capacity to 
the  average  booked  capacity  for 
each day of the period is below 80% 

or 

•  At  least  60  days  the  network  user 
nominates  over  80%  of  the  booked 
capacity  and,  later  on,  the  user 
renominates  half  or  below  half  the 
amount initially nominated 

•  For 

two  successive  periods  of  6 
consecutive months, from 1st October or 
1st  of  April, 
the  daily  scheduled 
quantities  for  the  network  user  at  the 
network point are, on average, less than 
80% of the user’s booked capacity at the 
network point for a period greater than 
or equal to one year 

and 

•  Teréga  has  not  been  able  to  satisfy  at 
least  one  duly  justified  request  from 
another  network  user  for  an  annual 
booking of capacity at the network point 

Trigger 
mechanism 

If either of the activation conditions 
apply 

If a request is received from a network 
user resulting in meeting the activation 
conditions 

Amount of 
capacity released 

Based on the difference between full 
utilization and actual utilization of the 
network point for each of the periods 

Capacity to accommodate the requests of 
the other network users 

Period of 
released capacity 

Capacity is released for the following 
gas year 

In accordance with the requests of the 
other network users 

To ensure the establishment of mechanisms with consistent elements, the NRAs of Belgium, the 
Netherlands and the UK drew up a vision on the implementation of the LT UIOLI mechanism37.  This 

37 ACM, Ofgem, CREG – Vision Paper LT UIOLI (link) 

32 

            
       
 
 
 
 
document  provides  guidelines  that  ensure  a  common  understanding  of  the  key  aspects  of  the 
mechanism, including: 

• 

• 

• 

• 

• 

the procedure for activating the mechanism 

definitions of effective contract duration of more than one year 

the  activation  conditions  (definition  of  contractual  congestion  and  systematically 
underutilized point, request for capacity) 

cases  where  unused  capacity  is  considered  to  be  sold  on  the  secondary  market  under 
reasonable conditions 

proper justification provided by the network user 

•  methodology for defining the capacity to be released 

3.4  Other mechanisms to manage congestion 

The  TSOs  apply  market-based  measures  to  ensure  the  efficient  use  of  their  network.  These 
measures  can  work  complementarily  with  CMPs  (e.g.,  use  of  FDA  UIOLI  and  use  of  interruptible 
capacity) or may be used first with CMPs acting as options of last resort (e.g., activation of a buy-
back after all market measures have been exhausted). They could also compete with CMPs, in the 
case of a network user deciding to sell its firm capacity on the secondary market or surrender it to 
the TSO. 

The offering of interruptible capacity is considered by the TSOs and NRAs as a key instrument to 
maximize  the  utilization  of  a  network  point  on  a  daily  basis.  If  there  is  booked  but  unused  firm 
capacity, nominations of interruptible capacity allow other network users to access the system, and 
the TSO to lift contractual congestion.   

Apart  from  selling  daily  and  longer-term  interruptible  capacity,  the  TSOs  can  also  use  over-
nominations to implicitly allocate within-day interruptible capacity. Over-nomination provides more 
intra-day flexibility to the TSOs, by allowing them to offer unused capacity during the day at each 
renomination cycle, and thus to better accommodate the network users’ needs in case of contractual 
congestion.  For  example,  Fluxys  in  Belgium  allows  booking  of  within-day  interruptible  capacity 
through over-nomination (over-nomination capacity)38 at its interconnection points, on the basis of 
the following principles: 

•  Over-nomination is activated if all firm capacity has been sold after the day-ahead or within-

day auction. 

• 

• 

The TSO notifies network users via urgent market message, on the Electronic Data Platform 
that over-nomination has been activated. 

If over-nomination has been activated by the TSO, then over-nomination capacity can be 
implicitly allocated to a network user by submitting a nomination exceeding their booked 
capacity. 

•  Over-nomination capacity is allocated until the end of the gas day, on a  first-come first-

served basis. 

• 

The  network  user  is  charged  for  allocated  over-nomination  capacity  at  the  interruptible 
tariff.  

38 Over-nomination is the procedure where a network user submits at any time nominations higher than their booked capacity 

at that network point, with a view to contracting within-day interruptible capacity. 

33 

            
       
 
 
 
In France, the TSOs offer an alternative service, the Use-it-and-Buy-It (UBI), to maximize the use 
of capacity in their system. This service makes it possible to offer day-ahead and within-day any 
capacity  that  has  been  booked  but  left  unused  (non-nominated)  to  other  network  users,  as 
interruptible capacity. The UIB allows the TSOs to directly offer the aggregate unused capacity to 
the  market,  providing  a  straightforward  way  for  the  capacity  to  be  allocated.  NaTran  (former 
GRTgaz) offers UBI capacity at its entry and exit IPs and at the entry from the Dunkirk LNG terminal, 
while Teréga offers it at the VIP Pirineos and Lussagnet UGS. The key principles of the UBI product 
are the following: 

• 

The TSO may offer capacity via UBI, only once a threshold of 98% of the firm capacity at 
the network point has been booked. 

•  At each nomination / renomination cycle, the TSO determines the unused firm capacity that 
can  be  offered  via  the  UBI,  as  the  difference  between  the  operational  capacity  of  the 
network point and the aggregate nominations of all network users. The offered UBI capacity 
is posted by the TSO at its electronic platform. 

• 

To  request  UBI  capacity,  network  users  submit  nominations  exceeding  their  firm  booked 
capacity. The requested UBI includes the interruptible capacity requested by the user (UBI 
request within the capacity rights), and additional capacity requested (UBI request above 
the capacity rights). 

•  UBI capacity is allocated at the end of each nomination/renomination cycle. If the requests 
for UBI capacity exceed the offer, then UBI capacity within the users’ rights is allocated first 
and UBI above the capacity rights is allocated afterwards. UBI requests are allocated on a 
pro-rata basis.  

• 

If the primary owners of capacity re-nominate during the following cycles, then the use of 
UBI capacity is partially or fully restricted (the firm capacity holders’ right to nominate is 
thus not withdrawn from them, capacity being reallocated via UBI on an interruptible basis 
only). 

The secondary market implicitly mitigates contractual congestion, by allowing users to dispose of 
their booked but unused capacity. This includes the possibility of selling firm capacity rights before 
they are released through the LT UIOLI mechanism. Some TSOs offer flexible rules to the network 
users seeking to sell their capacity rights, in order to facilitate secondary trade and increase the 
transactions. For example, FGSZ in Hungary allows users not only to sell their yearly, quarterly and 
monthly capacity products, but also to sell part of them from the 1st day of a given month until the 
end of the product. 

3.5  Congestion management at other gas infrastructure 

3.5.1  CMPs at LNG terminals 

Article 11 of the recast Gas Regulation (EU) 2024/178939 requires operators of LNG terminals to 
include  in  their  contracts  measures  to  avoid  capacity  hoarding,  without,  however,  specifying  the 
CMPs  to  be  applied,  but  instead  requiring  operators  to  make  unused  capacity  available  in  the 
primary market and to allow secondary trading of capacity rights. The operators of terminals (LSOs) 
with regulated access have put in place measures to manage congestion. Congestion management 
rules also apply at terminals that have received third-party access exemption40.  

39 Previously Article 17 of the Gas Regulation (EC) 715/2009. 

40 Such information is available in the Commission’s decisions granting exemption to these terminals. 

34 

            
       
 
 
 
Table 7 provides an overview of the CMPs applied at the terminals of each Member State. In principle 
the  mostly  used  mechanisms  are  surrender  of  capacity,  UIOLI,  or  use-it-or-sell-it  (UIOSI).  An 
OS+BB  mechanism  applies  only  at  the  Spanish  LNG  terminals41.  The  LSOs  apply  additional 
measures  that  provide  flexibility  in  using  the  terminals’  capacities  and  can  enhance  the  efficient 
utilization of their terminals. For example, secondary capacity trading is possible at all terminals, 
while often the operators may offer, during the year, available capacity in shorter-term and spot 
products. 

  Table 7: Congestion management measures at regulated LNG terminals of each Member State 

Surrender 

UIOLI / UIOSI 

OS+BB 

 42 

 

 

 

 

 

 

Belgium 

Croatia 

France43 

Finland 

Germany 

Greece44 

Italy 

Lithuania 

Netherlands 

Poland 

Portugal45 

Spain 

 

 

 

 

 

 

 

 

N/A 

 

 

Although the principles followed in the congestion management measures applied are similar, there 
are significant differences from one terminal to another regarding their design and processes. This 
is  linked  to  the  fact  that  not  all  terminals  offer  to  their  users  the  same  services  and  capacity 
products. For example, the Spanish rules for congestion management at the LNG terminals provide 
for short-term and long-term UIOLI of regasification capacity as well as a UIOLI process for terminal 
slots, while the rules of the Greek Revythoussa LNG terminal include a capacity release mechanism 
for  systematically  unused  regasification  capacity.  Other  terminals,  such  as  the  Belgian  facility  in 
Zeebrugge apply a UIOSI principle, to compel terminal users to trade their unused capacity. 

3.5.2  CMPs at underground gas storages 

The UGSs operate under a different overall framework compared to LNG terminals, as third-party 
access to the facilities can be either regulated or negotiated. This has an impact on the operation 
of the facilities, and subsequently on how potential contractual congestion can be managed. If the 

41 Different types of congestion measures apply for the different services offered by the Spanish terminal operators. These are 

described in more detail in the country brief for Spain of Annex I. 

42 Surrendered capacity at the Zeebrugge terminal is offered by the TSO at the secondary market and not treated as primary 

capacity. 

43 For the terminals Fos-Tonkin, Montoir-de-Bretagne and Fos-Cavaou. 

44 A surrender mechanism applies at the Alexandroupolis FSRU and a UIOLI at the Revythoussa terminal. 

45 Market measures, such as secondary capacity trading, are used at the Sines terminal.  

35 

            
       
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
storages are regulated, the NRA can set rules to address congestion, while at negotiated facilities 
it is up to the storage operator to ensure the efficient use of its capacity. 

The measures that some Member States put in place to ensure storage filling, as a result of applying 
the Gas Storage Regulation46, have impacted access to the storage facilities. Measures obligating 
market participants to store gas, or entities to establish strategic reserves, often leave limited to 
no  capacity  available  for  commercial  use.  The  capacity  allocation  mechanisms  applied  are 
sometimes  giving  priority  to  stakeholders  with  stockholding  obligations,  in  order  to  ensure  that 
sufficient  capacity  is  immediately  made  available  to  fill  the  storage,  without  having  to  apply 
additional mechanisms to release any booked but unused capacity. 

Furthermore, storage system operators (SSOs) can offer diverse products for the use of the storage 
capacity. In many cases only annual or shorter-term storage capacity is offered, while interruptible 
products  may  also  be  available.  This  limits  the  usefulness  of  a  long-term  capacity  release 
mechanism or the need of a storage user to surrender long-term booked capacity. SSOs are also 
providing  to  users  the  possibility  to  trade  their  capacity  rights  at  a  secondary  market,  providing 
additional flexibility on the utilization of capacity. 

Nevertheless,  the  SSOs  of  some  Member  States  are  applying  mechanisms  to  explicitly  address 
contractual congestion (Table 8). Use-it-or-lose-it mechanisms are mostly used, while in Poland a 
capacity  surrender  process  is  in  place  and  in  Spain  the  SSOs  have  the  possibility  to  provide 
additional capacity through OS+BB. 

Table 8: Congestion management measures at underground storage facilities 

Surrender 

UIOLI 

OS+BB 

Austria 

Belgium 

Czech Republic 

France 

Germany 

Poland 

Spain 

 

 

 

 

 

 

 

 

The mechanisms applied in each Member State are different, based on the national regulations for 
storage access and aiming to cover cases fit for the particular market. For example, some UIOLI 
mechanisms, e.g., in Austria and Germany, were put in place in 2022 exclusively to release capacity 
held by Gazprom that was booked but unused.   

3.6  Utilization of congestion revenues 

The main revenues of a TSO resulting from congestion at IPs are generated from the auction premia 
due to the higher capacity needs vis-à-vis the offered available capacity. The sales of interruptible 
capacity are an indirect result of congestion, as these capacity products are only sold in case all 
firm capacity has been allocated. 

46 Regulation (EU) 2022/1032 of the European Parliament and of the Council amending Regulations (EU) 2017/1938 and (EC) 

No 715/2009 with regard to gas storage (link). 

36 

            
       
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Article 19 of the Network Code on Harmonized Transmission Tariffs47 (TAR NC) gives the flexibility 
to the NRAs to decide whether the revenues resulting from auction premia can be used to decrease 
network tariffs or directed to investments for reducing physical congestions at the gas system. Many 
NRAs include in their tariff regulations both options of using premia for reducing the allowed revenue 
or for investment, allowing the NRA to decide during each tariff revision. The interviews with the 
stakeholders have indicated that in most cases the NRAs prefer to use revenues from auction premia 
as a deduction from expenses to be covered by the allowed revenue. The revenues were used to 
address physical system needs only in a few cases,  for example in Austria and in Belgium some 
revenues from auction premia were used in the past for increasing the interconnection capacity with 
Germany. 

Apart from auction premia, the TSOs may also collect revenues and incur costs from the application 
of CMPs. The allocation of oversubscribed capacity results in additional revenues, while in case of 
buy-back  the  TSO  must  compensate  the  network  users.  The  NRAs  can  decide  on  splitting  the 
revenues  generated  from  the  OS+BB  mechanism  between  the  TSO  (profit)  and  the  users  (a 
decrease  in  allowed  revenue)  as  an  incentive  to  the  TSO  to  undertake  the  risk  of  offering 
oversubscribed capacity. For example, in Spain, where additional capacity is offered by the TSO, 
the NRA has decided to return 90% of the revenues to the system and assign the remaining 10% 
to the TSO. 

Revenues from other CMPs are managed differently by the Member States. As discussed in Sections 
3.2.3 and 3.2.4, each TSO follows its own approach for capacity that has been reallocated following 
its voluntary (surrender) or mandatory (LT UIOLI) release. For example, some TSOs share with the 
user  releasing  capacity  the  additional  income  due  to  a  price  differential  between  the  originally 
booked and reallocated capacity. Other TSOs only require the user to pay in case of a deficit. Some 
TSOs share an auction premium for the reallocated capacity with the user releasing capacity, while 
others do not. 

In most Member States, there is no explicit reporting of the congestion revenues accumulated by 
the  TSO  and  how  these  were  used,  for  example  the  extent  to  which  these  contributed  to  tariff 
reduction. Depending on the NRA’s requirements, some information may be published. For example, 
in the Netherlands, during the tariff approval process, the TSO indicates the net revenues from the 
OS+BB  mechanism  (income  from  additional  capacity  sold  and  costs  of  capacity  buy-back) 
separately from the rest of its revenues, for transparency reasons.  

3.7 

Impact of decarbonization on congestion at gas systems 

The  transition  towards  a  decarbonized  gas  market  creates  changes  to  the  current  operation  of 
natural gas systems. This might imply challenges in regulating CMPs.  

A  decarbonized  gas  market  may  result  in  three  substantial  changes  for  the  gas  system:  less 
methane  transported,  more  blended  hydrogen  in  gas  networks,  more  biomethane  and  other 
alternative gases (synthetic gases) or a combination hereof. These changes would result in not only 
a change in quantities but also a change in flows and location of production and demand. This, in 
turn, can create changed flow patterns and thus a mismatch between the current system’s operation 
and its future needs, risking congestion while increasing the need for fit-for-purpose CMPs. Should 
demand  in  general  decline  and  current  capacities  exceed  the  necessary  size,  in  the  short-to-
medium-term there may be less contractual congestion. In the long-term, there may be actions of 

47 Commission Regulation (EU) 2017/460 of 16 March 2017 establishing a network code on harmonised transmission tariff 

structures for gas  (link). 

37 

            
       
 
 
 
decommissioning48  for  repurposing  or  dismantling  impacting  available  capacities  for  natural  gas 
transmission. 

To sufficiently understand potential challenges from decarbonization of the gas system, we have 
gathered market intelligence through two channels: 

• 

• 

interviews conducted with TSOs and NRAs, and 

a  survey  that  is  shared  with  relevant  stakeholders,  including  TSOs,  NRAs,  and  network 
users.  

The main findings are described below, after briefly introducing both of the mechanisms used to 
gather market intelligence. 

We  conducted  interviews  for  the  purpose  of  understanding  the  CMPs  applied  in  the  EU  Member 
States. These interviews allowed for covering one question on the impact of decarbonization of the 
gas market. Where feasible, we inquired on the following question: Do you consider that there will 
be changes in the scope and needs for congestion management resulting from the decarbonization 
of the energy sector? 

During  the  interviews  conducted  with  TSOs  and  NRAs,  we  had  the  opportunity  to  inquire  for 
information about the impact of decarbonization on CMPs. Most TSOs and NRAs interviewed agree 
that there will be at least a small if not large decline of gas usage in the natural gas system in the 
future.  The  first  conclusion  is  therefore  that  there  will  be  no  congestion  due  to  this  decreasing 
quantity in the network. Whether decommissioning for the purpose of early repurposing will have 
an impact on congestion was hard to evaluate for the interview attendees and the main notion is 
that it is too early to conclude on any impact of lower gas volumes and increasing decommissioning. 

The  survey  focused  on  the  relevance  between  decarbonization  of  the  gas  system  (excluding 
dedicated hydrogen systems) and the need to manage congestion. The TSOs, NRAs and network 
users surveyed provided inputs across three thematic areas: prospects for gas demand, network 
changes,  and  congestion  management  procedures.  Responses  came  from  14  EU  countries, 
revealing insights on gas demand trends, infrastructure adjustments, CMP adequacy, and long-term 
planning: 

•  A majority (65%) of respondents anticipate a slight decline in natural gas demand by 2040 
due  to  sector  decarbonization,  with  future  demand  relying  more  on  renewable  and  low-
carbon gases. 

•  Most  respondents  (83%)  do  not  foresee  increased  congestion  due  to  infrastructure 
decommissioning, while opinions vary on the sufficiency of current CMP mechanisms. 

•  Significant uncertainty in long-term planning impacts (48%) is driven by future gas demand 

fluctuations and influenced by neighboring countries' decarbonization strategies. 

•  Mixed responses indicate that some stakeholders have begun repurposing gas networks for 

hydrogen, but many remain uncertain about future developments. 

•  The future role of blended hydrogen remains unclear; 30% see an increased role, 17% do 

not, with others preferring dedicated hydrogen pipelines. 

•  Biomethane is expected to play a significant role in future operations, with 65% anticipating 
its  increased  importance  predominantly  affecting  distribution  networks  and  potentially 
reversing flows from distribution to transmission networks due to surplus production. 

A detailed evaluation of the responses to the survey is provided in Annex IV. 

48 Directive (EU) 2024/1788 on common rules for the internal markets for renewable gas, natural gas and hydrogen. 

38 

            
       
 
 
 
The survey highlights varying expectations and uncertainties among stakeholders regarding future 
natural  gas  demand,  CMP  measures,  infrastructure  planning,  and  the  roles  of  blended  hydrogen 
and  biomethane.  While  some  anticipate  significant  changes  and  adaptations,  others  foresee 
stability, reflecting varied strategic approaches to decarbonization and energy transition. 

The  CMP  focused  responses  to  the  survey  indicate  that  the  need  for  additional  CMPs  to  manage 
contractual congestion resulting from decarbonization of the natural gas systems is expected to be 
limited, and in any case not an issue to be tackled within a short-term horizon. It is still unclear 
how gas flow patterns will change, and it is likely that any emerging congestion will be physical and 
not contractual. For this reason, decarbonization is not examined further in this study as a potential 
challenge to the implementation of the CMPs.  

39 

            
       
 
 
4.  Analysis of congested network points 

4.1  Overview of points selected 

Quantitative analysis was carried out on selected network points to assess the actual application of 
CMPs and the extent to which they contributed to the efficient network operation. The points to be 
examined were selected taking into account the following criteria: 

•  Sides  of  network  points  (IPs  and  other  network  points)  for  which  the  TSO  applied  CMPs 

between 2021 and 2024 (according to ENTSOG’s transparency platform). 

• 

• 

IP sides identified as congested in 2022 and 2023 according to ACER’s congestion reports. 

IP sides which are not included in points 1 and 2, but for which several capacity auctions 
for daily, monthly or quarterly products resulted in auction premia, indicating that demand 
for firm capacity exceeded the offered one. 

In total 174 IPs are analysed, presented in Annex 2. This list covers: 

•  35 TSOs from 20 Member States49, providing a wide geographical coverage in the analysis. 
Most TSOs are from Germany, due to the application of CMPs at multiple of their network 
points.  

•  3 interconnectors (BBL, IGB, TAP). 

• 

IPs with non-EU Member States (e.g., Kiskundorozsma 2 IP between Hungary and Serbia, 
Kipi IP (TAP) between Greece and Turkey, Kyustendil (BG)/Zidilovo (MK) between Bulgaria 
and North Macedonia). 

•  Network points other than IPs (entries from UGSs of Thyssengas in Germany). 

The data analysed covers the period from 1st October 2021 up to 30th September 2024, i.e. the gas 
years 2021/22, 2022/23 and 2023/24, as well as a small part of gas year 2024/25. 

Data on auctions was not available for all examined network points. Capacity at 3 IP sides in the 
Baltics  is  allocated  via  implicit  allocation.  Furthermore,  16  IP  sides  located  in  Germany  and  the 
Netherlands are dual model points (presented in Annex II), which continue to operate (and release 
capacity through CMPs) only for the past long-term contracts already in place, while currently their 
capacity  is  being  auctioned  as  part  of  the  formed  VIPs.  For  these  points  all  data  except  auction 
results was analysed.   

The quantitative analysis, presented in the following Sections 4.2 to 4.4, focuses on the following 
factors and indicators:  

•  Nature  of  congestion:  examines  whether  a  network  point  is  physically  or  contractually 

congested. 

• 

Extent of unmet demand: examines whether the occurrence of demand for firm capacity 
exceeding  offered  capacity  at  the  auctions,  which  is  used  to  identify  congested  IP  sides, 
was an isolated or a recurring incident. 

•  Release  of  capacity  by  CMPs:  examines  the  amount  of  capacity  released  by  CMPs  at  a 

network point. 

49 Out of the 23 Member States with the obligation to implement CMPs, only Estonia, Finland, Ireland and Latvia are not 

covered with any network point. 

40 

            
       
 
 
 
•  Surrendering  of  capacity  during  congestion:  Examines  whether  capacity  was  voluntarily 
released  (surrendered)  by  network  users  to  the  TSO  when  a  network  point  was  highly 
utilized. 

•  Use of oversubscribed capacity50: Examines the amount of additional capacity offered at a 

network point and the part of it that was booked. 

•  Application of LT UIOLI: Examines the impact of long-term capacity released on the capacity 

of a network point. 

•  Application of FDA UIOLI: Examines the extent to which the renomination restrictions at a 

network point were activated when the point was highly utilized. 

During the quantitative analysis we also examined the validity and availability of publicly available 
data concerning CMPs. The results of this analysis are discussed in Section 4.5. 

Apart from the analysis carried out across all the examined network points, detailed analysis was 
carried out for selected network points, to provide a better view of how the CMPs were applied and 
how contractual congestion was addressed. These case studies, presented in Annex III, cover the 
following IPs: 

• 

• 

• 

IP  Baumgarten  (Slovakia  to  Austria  direction),  which  has  been  identified  as  formally 
congested and at which FDA UIOLI applies on the Austrian side and OS+BB at the Slovak 
side. 

IP Dravaszerdahely (Croatia to Hungary direction). This IP was congested during the energy 
crisis, resulting in the NRA applying an FDA UIOLI mechanism. 

IP  Kulata  (BG)  /  Sidirokastron  (GR)  (Bulgaria  to  Greece  direction),  at  which  OS+BB  has 
been offered with high point utilization. 

•  VIP-BENE (Belgium to Netherlands direction), which has been highly utilized, and additional 

capacity has been offered only on the Dutch side. 

•  VIP Pirineos, at which OS+BB was jointly applied by the TSOs. The offering of UBI capacity 

on the French side is also examined. 

•  VIP-TTF-THE-H, at which capacity is released through oversubscription on the Dutch side 

and through FDA UIOLI on the German side. 

With respect to the operation of LNG terminals, input provided by the NRAs during the interviews 
indicated that, apart from some surrendering of regasification capacity, there was very limited need 
to  apply  CMPs  to  tackle  contractual  congestion.  The  utilization  of  the  Polish  Świnoujście  LNG 
terminal is analysed in Annex V, as an example of the periodic use of LNG facilities’ capacity. 

In the case of UGSs, the application of measures to manage booked but unused capacity was very 
limited. Congestion management measures were activated in 2022, only to release capacity held 
by Gazprom. Therefore, there is no added value in analysing the actual use of CMPs in UGSs further.  

4.2  Nature of the congestion 

Although the energy crisis of 2022 resulted in increased occurrences of physical congestions in the 
European  gas  system,  there  were  still  situations  of  underutilized  network  points,  including 
contractually  congested  points  where  other  users  were  interested  in  accessing  firm  capacity. 
Assessing  the  nature  of  congestion  at  the  examined  network  points  to  identify  the  cases  of 

50 The buy-back part of the OS+BB mechanism is not examined as in most cases no capacity was bought back by the TSOs. 

41 

            
       
 
 
 
contractual congestion is important, in order to understand the extent to which the application of 
CMPs could contribute to enhancing the efficient use of the gas system. 

To identify the network points at which physical congestion occurred during each gas year, and the 
magnitude of this congestion, we examined the number of days that each network point had its 
firm  capacity  fully  booked  and  fully  utilized.  The  figure  below  presents  a  grouping  of  the  points 
based on the number of days on which physical congestion occurred. 

Figure 9: Number of days with physical congestion 51 at the examined network points52 

As shown in the graph, most network points (64 points) with at least 1 day of physical congestion 
were observed in gas year 2022/23, however most of these points were congested for time intervals 
aggregating to less than 50 days over the year. Congestion was more severe, and more network 
points were operating at their technical limits for longer periods, in gas year 2021/22. The network 
points  which  exhibited  the  highest number  of  days  with  physical  congestion  during  the  gas  year 
2022/23 are presented in the table below. The points that were congested for the longest period 
were IPs between Germany, Belgium and the Netherlands, as a result of the significant changes in 
the gas flow patterns and directions in the region. 

Table 9: Network points with most days of physical congestion in gas year 2022/23 

TSO 

GUD 

Fluxys 
Belgium 
Fluxys 
Belgium 
OGE 
GRTgaz 

Point 

Bunde (DE) / Oude Statenzijl 
(H) (NL) (GUD) 

Zeebrugge IZT 

VIP THE-ZTP 

Emden (EPT1) (OGE) 
VIRTUALYS 

Direction 

Days of physical congestion 
GY2021/22  GY2022/23  GY2023/24 

entry 

entry 

exit 

entry 
exit 

314 

206 

179 

8 
84 

256 

210 

234 

179 
172 

299 

21 

53 

90 
157 

During the examined period there were points that were fully booked but underutilized, some of 
which were so for a prolonged period of time. To assess the extent to which the examined network 
points were underutilized, we estimated the number of days that the firm capacity of each point 
was sold out and at the same time it was used below 80%. The figure below presents a grouping 
of the points based on the number of days with booked but unused capacities. 

51 Number of days on which the network point was fully booked and fully utilized. 

52 Source: Consultant’s elaboration using data from the TSOs’ websites. 

42 

            
       
 
 
 
 
Figure 10: Number of days with booked but unused capacities53 at the examined network points54 

As shown in the graph, most network points with booked but unused capacity were observed in gas 
year 2022/23 (54 points)55. The occurrence of underutilization drastically dropped in the subsequent 
year,  with  the  number  of  points  exhibiting  at  least  one  day  of  high  booking  and  low  utilization 
decreasing  to  less  than half  compared to those in  gas  year  2022/23.  Many  of  these  points  were 
physically congested and underutilized at different periods within the same gas year. The ratio of 
full utilization to underutilization differs for each network point.   

The network points which exhibited the highest number of days with booked but unused capacity 
during the gas year 2022/23 are presented in the table below. Terranets’ network points RC Basel 
and RC Linday have remained underutilized throughout the 3 examined gas years. IP Csanadpalota 
(Transgaz exit) and other points exhibited a steep increase in underutilization in gas year 2022/23 
compared to the other gas years.  

Table 10: Network points with most days of booked but unused capacity in gas year 2022/23 

TSO 

Point 

Direction 

terranets bw  RC Basel 
terranets bw  RC Lindau 
Transgaz 
DESFA 

Gastransport 
Nord 

Csanadpalota 
Kulata (BG) / Sidirokastron 
(GR) 
Bunde (DE) / Oude 
Statenzijl (L) (NL) (GTG 
Nord) 

exit 
exit 
exit 
entry 

entry 

Days of underutilization 
GY2021/22  GY2022/23  GY2023/24 
365 
365 
306 
276 

362 
365 
101 
158 

353 
366 
197 
174 

144 

229 

134 

Low utilization of booked firm capacity does not necessarily impact the efficient use of that network 
point, unless there is interest from other market players to use this capacity. To assess the extent 
to which the examined network points are contractually congested (based on the definition used in 
this study, as described in Section 2.1), we estimated the number of days that the firm capacity of 
each point was booked and underutilized, and at the same time there were unmet requests for firm 

53 Number of days on which the network point was fully booked, and utilization was below 80%. 

54 Source: Consultant’s elaboration using data from the TSOs’ websites. 

55 The underutilized network points identified above do not include cases of network points that are on the verge of being fully 

booked and at the same time the utilization level of this booked capacity is low. For example, at the eustream exit of IP 
Baumgarten over 90% of capacity was booked throughout the 3 examined gas years, but its utilization remained low. A case 
study of this network point is presented in Annex III.  

43 

            
       
 
 
 
 
capacity.  The  figure  below  presents  a  grouping  of  the  points  based  on  the  number  of  days  with 
contractual congestion. 

Figure 11: Number of days with contractual congestion 56 at the examined network points 57 

As shown in the graph, situations of contractual congestion occurred mainly in gas year 2022/23 
(27 points) and to a lesser extent in 2021/22 (17 points). Some points (6 in 2022/23) were severely 
congested, on over 100 days in a year, while many occurrences were observed on just a few (1 – 
10) days over the whole year.  

The network points which exhibited the highest number of days with contractual congestion during 
the gas year 2022/23 are presented in the table below. Transgaz exit at IP Csanadpalota and DESFA 
entry at IP Kulata (BG) / Sidirokastron (GR) were also two of the most underutilized network points 
(Table 10), and other market participants were interested to book this capacity. VIS Pirineos and 
VIP BENE were also congested for multiple days in gas year 2022/23.   

Table 11: Network points with most days of contractual congestion in gas year 2022/23 58 

TSO 

Point 

Direction 

Transgaz 
DESFA 

TERÉGA 
Enagas 
GTS 

Csanadpalota 
Kulata (BG) / Sidirokastron 
(GR) 
VIP PIRINEOS 
VIP PIRINEOS 
VIP BENE 

exit 

entry 

entry 
exit 
entry 

Days of underutilization 
GY2021/22  GY2022/23  GY2023/24 
306 

100 

197 

158 

100 
97 
3 

276 

158 
153 
133 

84 

35 
72 
0 

As  shown  in  the  figure  below,  the number of  IPs  with  at least  some  days of  physical  congestion 
each of the examined gas years was similar to that of IPs with booked but underutilized capacity. 
The number of contractually congested IPs was smaller, as it also takes into account the unfulfilled 
capacity requests of network users. Some IPs were contractually congested only for 1 to 2 months 
within the gas year. At other IPs congestion was longer term, occurring for 3 months or more. The 
latter case is similar to the criterion 2.2.3.(1).(a) of the CMP Guidelines, which sets the threshold 
of congested IP sides at 3 firm capacity products with a duration of one month. 

56 Number of days on which the network point was fully booked, utilization was below 80% and at the same time there were 

unmet requests for firm yearly, quarterly or monthly firm products with runtime that includes the respective day. 

57 Source: Consultant’s elaboration using data from the TSOs’ websites. 

58 Number of days on which the network point was fully booked, utilization was below 80% and there was unmet requests of 

network users for yearly, quarterly or monthly capacity.  

44 

            
       
 
 
 
 
Figure 12: Number of network points with physical congestion and contractual congestion  

4.3  Extent of unmet demand 

Based on the criteria set out in point 2.2.3.(1) of the CMP Guidelines, IPs are identified as congested 
by the number of occurrences of capacity demand exceeding offer (unmet demand) for monthly, 
quarterly and yearly firm capacity products. This unmet demand however could concern just a small 
part of the offered capacity, or it could account for multiples of the capacity made available by the 
TSO.  To  assess  the  extent  to  which  demand  for  firm  capacity  could  not  be  accommodated,  two 
dimensions need to be considered: 

• 

Frequency:  The  number  of  auctions  for  a  firm  capacity  product  at  which  unmet  demand 
occurs, vis-à-vis the total number of auctions for that product. 

•  Severity: The amount of capacity demanded for a firm capacity product in an auction, vis-

à-vis the amount of capacity offered at that auction. 

The  figure  below  shows  the  frequency  and  average  severity  of  unmet  demand  for  bundled  and 
unbundled capacity at the examined network points for each gas year59. The number of points with 
unmet demand for quarterly and yearly products increased in gas year 2022/23, which reflects the 
increased congestion during the energy crisis.  

Figure 13: Frequency and severity of unmet demand for capacity at the examined network points60 

GY 2021/22 – Bundled capacity auctions 

GY 2021/22 – Unbundled capacity auctions 

59 The data is presented on the basis of the runtimes of the capacity products and not the time that they were auctioned. 

60 Source: Consultant’s elaboration using auction data from the capacity booking platforms PRISMA, RBP, GSA. 

45 

            
       
 
 
 
 
 
 
GY 2022/23 – Bundled capacity auctions 

GY 2022/23 – Unbundled capacity auctions 

GY 2023/24 – Bundled capacity auctions 

GY 2023/24 – Unbundled capacity auctions 

The  severity  of  unmet  demand  provides  an  indication  of  the  network  users’  interest  to  use  a 
particular  network  point,  which  could  also  translate  into  the  booking  of  interruptible  capacity. 
Contractually congested points with high demand for capacity would potentially also benefit more 
from the application of CMPs. 

4.4  Application of CMPs 

4.4.1  Release of capacity though by CMPs 

The CMPs were activated to release capacity at 115 network points in gas year 2021/22, decreasing 
to 106 points in 2022/23 and 91 points in 2023/24. FDA UIOLI was used at most network points, 
mainly in Germany and Austria (where the mechanism applies at all network points and not only 
those identified as congested). Almost half of the points at which capacity was surrendered and at 
which capacity was oversubscribed are in the Netherlands. Capacity was released using the long-
term UIOLI mechanism only in Hungary and in the Czech Republic61. The Figure below shows the 
number of network points at which CMPs were activated each gas year (in some cases two or more 
mechanisms were applied at the same point). 

61 The activation of the LT UIOLI mechanism during the examined gas years was not related to capacity hoarding but was 

used as a measure to manage contractual issues. For example, in Hungary the mechanism was used to withdraw capacity 
from users that were bankrupt (i.e. it was not used as a CMP).  

46 

            
       
 
 
 
 
 
 
 
 Figure 14: Number of network points at which capacity was released per CMP62 

In aggregate terms, the largest amount of capacity was released in gas years 2021/22 and 2022/23 
in the Netherlands, as oversubscribed capacity. A large amount of capacity was also surrendered 
each year at 2 IPs in the Czech Republic. The release of capacity per Member State for each gas 
year is presented below (only Member States releasing capacity are included in the graphs). 

Figure 15: Aggregate annual capacity released at each Member State per CMP63 

GY 2021/22 

GY 2022/23 

62 Source: Consultant’s elaboration using data from ENTSOG TP and TSOs’ websites. 

63 Source: Consultant’s elaboration using data from ENTSOG TP and TSOs’ websites. 

47 

            
       
 
 
 
 
 
 
GY 2023/24 

On average64, most capacity was released at the Czech IPs in all three examined gas years, applying 
surrender of capacity, FDA UIOLI and LT UIOLI. A significant amount of additional capacity through 
oversubscription was made available in the Netherlands. In Germany, most capacity was released 
in gas year 2022/23, through the renomination restrictions set by the FDA UIOLI mechanism at all 
network points. 

Figure 16: Average annual capacity released at each Member State per CMP65 

GY 2021/22 

GY 2022/23 

64 The average capacity is estimated only for the days on which capacity was released through CMPs. 

65 Source: Consultant’s elaboration using data from ENTSOG TP and TSOs’ websites. 

48 

            
       
 
 
 
 
 
 
4.4.2  Surrendering of capacity during congestion 

GY 2023/24 

Capacity surrendered by network users was made available at IPs in Austria, the Czech Republic, 
Germany,  and  the  Netherlands.  Some  surrendered  capacity  was  also  released  in  Lithuania  and 
Latvia (gas year 2023/24) and in Poland (gas years 2021/22 and 2022/23)66. In most countries, 
long-term firm capacity was surrendered, resulting in amounts of capacity released for a long period 
of time, and often throughout the gas year (Figure 17). Even though capacity was surrendered at 
multiple IPs in the Netherlands, the average amount of capacity released at each point was limited. 
On the other hand, the capacity made available each gas year at the Czech IPs was very high. 

Figure 17: Network points per Member State at which surrendered capacity was released67 

Although in some cases surrendered capacity was made available by the TSOs on multiple days per 
year, its contribution to managing contractual congestion is limited only to the days when additional 
capacity was needed in the market due to the lack of firm capacity. For example, at VIP Brandov 
entry  of  NET4GAS,  surrendered  capacity  was  reallocated  only  when  utilization  of  the  point  was 
higher in gas year 2021/22 (surrendered capacity was reallocated on 63 out of the 360 days that it 

66 Depending on the capacity products surrendered, the capacity may have been released during the examined period or 
before that. For example, in Poland, the capacity made available in gas years 2021/22 and 2022/23 was surrendered in 
earlier periods, not during those gas years. 

67 Source: Consultant’s elaboration using data from ENTSOG TP and TSOs’ websites. 

49 

            
       
 
 
 
 
 
was made available), but almost no surrendered capacity was then sold in the subsequent years, 
when use of the point decreased (Figure 18). 

Figure 18: Capacity surrendered at VIP Brandov entry (NET4GAS)68 

3,000

2,500

2,000

1,500

1,000

500

0

d
/
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W
G

1
2
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0
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0

4
2
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0

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2
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9
0
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1
0

4
2
/
0
1
/
1
0

4
2
/
1
1
/
1
0

Surrendered capacity

Allocated capacity

Technical capacity

Allocations

Booked capacity

4.4.3  Use of oversubscribed capacity  

Additional capacities through oversubscription have been offered at: 

•  Both sides of the VIPs of Spain with France and Portugal. 

• 

• 

• 

The Dutch side of IPs with Belgium (Hilvarenbeek exit, VIP BENE entry/exit and VIP BENE-
L  exit),  Germany  (VIP  TTF-THE-H  entry/exit,  VIP  TTF-THE-L  exit)  and  Norway  (Emden 
(EPT1) (GTS) entry).  

The Greek side of IPs with Bulgaria (Kulata (BG) / Sidirokastron (GR) entry/exit) and TAP 
(Nea Mesimvria entry). 

The Slovak side of the IP Baumgarten exit, only until the end of 2021.  

The largest amount of additional capacity is being offered in the Netherlands, as already shown in 
Section 4.4.1. Apart from the Dutch IPs, in all other Member States the ratio of additional capacity 
provided  through  oversubscription,  vis-à-vis  the  technical  capacity  of  the  network  point  was 
between 5% and 10% (Figure 19).  

Figure 19: Additional capacity offered vis-à-vis the network points’ technical capacity 69 

68 Sources: NET4GAS. 

69 Source: Consultant’s elaboration using data from ENTSOG TP and TSOs’ websites. 

50 

            
       
 
 
 
 
 
 
The risk assessment methodology applied by some TSOs, following approval from the respective 
NRA, allows additional capacity to be offered when nominations are relatively low. As a result, there 
is  no  need  for  the  TSO  to  activate  the  buy-back  mechanism,  but  at  the  same  time,  the  market 
demand  for  additional  capacity  is  also  limited.  For  example,  at  VIP  Pirineos  entry  (Figure  20), 
Enagás offered additional capacity mainly when users’ requests to use their booked capacity were 
limited70. It should be noted that the TSO is offering additional capacity at low risk situations, even 
though it is allowed to keep 10% of the revenues from selling this capacity. 

Figure 20: Offering of additional capacity at VIP Pirineos entry (Enagás)71 

More interest for the oversubscribed capacity was observed at the Greek IPs (Figure 21). Additional 
capacity  was  offered  in  periods  with  very  high  capacity  bookings  and  high  use  of  capacity.  For 
example, at the (Kulata (BG) / Sidirokastron (GR) entry, over the past 3 gas years, DESFA offered 
additional capacity 187 days with utilization exceeding 90%72. Nevertheless, according to the NRA, 
there was no need for buy-back of capacity, because the TSO coped with technical limitations by 
using interruptible capacity. 

Figure 21: Booking of additional capacity at the Greek IPs73 

d
e
k
o
o
b

y
t
i
c
a
p
a
c

l

a
n
o
i
t
i
d
d
A

100%

80%

60%

40%

20%

0%

85%

78%

89%

76%

100%

0%

0%

0%

0%

Kulata (BG) / Sidirokastron (GR) -
entry

Kulata (BG) / Sidirokastron (GR) - exit

Nea Mesimvria - entry

GY-2021/22

GY-2022/23

GY-2023/24

70 Further details on the application of CMPs at VIP Pirineos are presented in the case studies of Annex III. 

71 Source: ENTSOG TP 

72 Further details on the application of CMPs at Kulata (BG) / Sidirokastron (GR) are presented in the case studies of Annex 

III. 

73 Source: Consultant’s elaboration using data from the TSO’s website. 

51 

            
       
 
 
 
 
 
 
 
 
4.4.4  Application of LT UIOLI 

In gas years 2021/22 and 2022/23 capacity was withdrawn from network users in Hungary using 
the LT UIOLI mechanism. According to the Hungarian TSO, activation of this mechanism was not 
related to congestion, but was used to release capacity from bankrupt users. 

During the examined period, capacity was also released in the Czech IPs VIP Brandov entry and VIP 
Waidhaus  exit  in  2023/24,  for  a  short  period  between  1st  January  and  4th  February  2024.  The 
withdrawn capacity accounted for 40% of the technical capacity at VIP Brandov and 91% at VIP 
Waidhaus. None of this capacity was reallocated to other network users. Activation of the LT UIOLI 
mechanism  was  not  due  to  capacity  underutilization  and  hoarding  at  the  IPs.  It  was  related  to 
specific conditions in the long-term agreements in force at these IPs (which were concluded before 
the CMP Guidelines entered into force), which could not be implemented by another IT functionality 
at the TSO’s electronic platform. 

The LT UIOLI mechanism was activated in the Czech Republic once in the past, at the exit of IP 
Cieszyn  (PL)  /  Český  Těšín  (CZ),  to  address  capacity  hoarding.  Underutilization  of  capacity  was 
identified in 2014, and the NRA triggered the mechanism in 2015, once capacity was requested by 
other network users. The administrative procedure of the NRA lasted around 9 months. Long-term 
capacity was then released at the Czech side of the IP from 2017 to 2021. 

4.4.5  Application of FDA UIOLI 

The  German,  Austrian  and  Croatian  TSOs  apply  the  FDA  UIOLI  mechanism  at  all  their  network 
points,  regardless  of  whether  they  have  been  identified  as  congested  or  not  and  have  released 
significant amounts of capacity due to renominations at their points. The mechanism has also been 
applied at IPs in Hungary, the Czech Republic, Italy and at the entry (Greece) and exit (Bulgaria) 
IGB interconnector. 

In the Czech Republic and at IGB the capacity was released only on days when utilization of the 
network points was limited. In Germany, Austria, Hungary and Italy capacity was made available 
during some days of high utilization, which indicates that this capacity could have been reallocated 
to other users.  

Figure 22: Days with capacity released through FDA UIOLI74 

74 Source: Consultant’s elaboration using data from ENTSOG’s TP. 

52 

            
       
 
 
 
 
 
4.5  Data validity and availability 

4.5.1  Data required to analyse CMPs 

The quantitative analysis of the CMPs’ application and impact requires a range of data, relating to 
the marketing of capacity, revenues from capacity bookings, utilisation of the network point and 
the activation of the CMPs. This data can indicate the nature of congestion (physical or contractual) 
at the network point, the financial impact of the unmet demand for capacity, the effectiveness and 
efficiency of the activation of CMPs. 

The type of data needed to carry out the analysis of a network point include: 

• 

Technical, booked and available capacity. 

•  Offered,  demanded  and  allocated  capacity  at  capacity  auctions  and  auction  premia,  for 

auctions of yearly, quarterly, monthly and daily capacity products. 

•  Daily nominations and allocations of volumes. 

• 

Interruptions of interruptible capacity. 

•  Release of capacity through surrender, FDA UIOLI or LT UIOLI. 

•  Oversubscribed capacity, capacity bought back by the TSO and buy back price. 

•  Reallocation of released capacity. 

•  Capacity rights traded at the secondary market. 

Such types of data can be available at the TSOs’ websites (or transparency platforms), at ENTSOG’s 
Transparency Platform (TP) and in the reports published by the booking platforms. During the data 
collection exercise for the analysis of the congested network points, the availability and quality of 
the data was examined, and the key findings are discussed below. 

4.5.2  Availability of data 

All the data required to analyse the CMPs are collected by the TSOs. The TSOs make some of this 
data available in the public domain, while the rest is privileged information shared with the NRAs 

53 

            
       
 
 
 
 
 
either  through  periodic  reports  or  upon  request.  The  table  below  provides  an  overview  of  the 
publication of information. 

Table 12: Availability of CMP data 

Type of data 

Relevance 

Public 

Privileged 

Source 75 

Technical, booked and available 
capacity 

Effectiveness/efficiency 

Offered and demanded capacity  

Nature of congestion 

Allocated capacity and premia 

Financial impact 

Daily nominations and allocations  Effectiveness/efficiency 

Interruptions of interruptible 
capacity 

Nature of congestion, 
effectiveness/efficiency 

Release of capacity through 
surrender, FDA UIOLI, LT UIOLI 

Effectiveness/efficiency 

Oversubscribed capacity 

Effectiveness/efficiency 

Capacity bought back  

Effectiveness/efficiency 

Reallocation of released capacity 

Effectiveness/efficiency 

Secondary capacity trades 

Effectiveness/efficiency 

 

 

 

 

 

 

 

 

TSOs’ websites 

Booking platforms 

Booking platforms 

TSOs’ websites 

TSOs’ websites 
and/or ENTSOG TP 

TSOs’ websites 
and/or ENTSOG TP 

TSOs’ websites 
and/or ENTSOG TP 

- 

- 

TSOs’ websites 
and/or booking 
platforms 

76 

 

77 

Data concerning the amount of capacity released through CMPs that was then reallocated to other 
network users is not published per network point, with the exception of very few TSOs (NET4GAS, 
Conexus). Such information is only available as aggregate for all EU Member States, on a bi-annual 
basis  in  ENTSOG’s  monitoring  reports  for  congestion  management.  Although  publication  of  this 
information is not mandated in the publication requirements set out in Chapter 3 of the Annex I to 
Regulation (EU) 2024/1789, it is important for assessing the effectiveness of the activation of CMPs, 
by comparing the released and reallocated capacity. 

None  of  the  TSOs  that  offer  additional  firm  capacity  through  oversubscription  publish  at  their 
websites  any  information  concerning  buy-back  of  this  capacity,  even  if  no  buy-back  occurred  in 
practice. Furthermore, only few of the TSOs that apply the OS+BB mechanism but do not actually 
offer additional capacity publish such information at their websites. 

4.5.3  Quality and validity of published data 

The  quality  of  the  collected  data  was  examined,  to  identify  potential  inconsistencies  and 
discrepancies in datasets published by different sources. Only the validity of the CMP data published 
at the TSOs’ websites and the ENTSOG TP was assessed. Potential discrepancies in data published 
in the reports of the booking platforms were not examined. 

75 For information that is published at the TSOs’ websites and the ENTSOG TP, only the first source is noted in the Table. For 

information that is published either at the TSOs’ websites or at the ENTSOG TP or both, both sources are noted. 

76 Based on the interviews with the NRAs and TSOs, most TSOs did not have to buy back oversubscribed capacity. This 

however is not published at the respective TSOs’ websites. 

77 Bilateral trades and/or trades facilitated by the TSOs may not be published but only managed internally by the TSO. 

54 

            
       
 
 
 
 
 
 
 
 
 
 
 
 
For some network points, the data published by the TSO at its website had considerable differences 
from the data available at the ENTSOG TP. Such discrepancies concerned daily technical, available 
and booked capacities as well as CMP data. 

Some TSOs publish CMP data at their websites but not on ENTSOG’s TP. The oversubscribed capacity 
by DESFA (IPs Kulata (BG) / Sidirokastron (GR) – entry and Nea Mesimvria – exit) and eustream 
(IPs Baumgarten – exit and Lanžhot – exit) are only available at their websites. Similarly, Conexus 
presents the surrendered capacity at IP Kiemenai – entry only as part of its published transmission 
data. 

An  additional  consistency  issue  on  the  data  available  at  ENTSOG’s  TP  is  that  in  some  cases  the 
information relating to the CMP capacities made available does not concern the activation of the 
CMPs to address congestion, but rather the use of the mechanisms foreseen in the Guidelines for 
other purposes. Indicatively: 

• 

• 

The TP presents data of capacity released through oversubscription by some German TSOs. 
However,  the  OS+BB  mechanism  was  used  after  the  market  merger  to  increase  the 
available firm capacity, and not to manage contractual congestion.  

In some cases, the capacity released through the LT UIOLI mechanism, reported in the TP,  
concerns  capacity  released  due  to  contractual  issues  and  is  not  related  to  capacity 
underutilization and hoarding.  

55 

            
       
 
 
 
 
 
5.  Regulatory shortcomings and potential interventions 

5.1  Areas of improvement 

Lessons  learned  and  regulatory  challenges  and  shortcomings  with  the  application  of  CMPs  were 
identified through the desktop analysis of the CMP rules, the quantitative analysis of the selected 
network points, the interviews with the EU NRAs and TSOs and the survey with stakeholders. The 
identified  issues  that  relate  to  topics  of  similar  scope  and  characteristics  have  been  grouped 
together into common areas of improvement, which include: 

•  Definition of congested points 

•  Scope of the CMPs 

• 

• 

Establishment of measures to manage congestion 

Effectiveness and efficiency of the CMPs 

•  Harmonization of rules between adjacent TSOs 

•  Management of congestion revenues 

• 

Transparency  

In  this  section,  for  each  area  of  improvement,  we  examine  the  identified  challenges  and 
shortcomings, define the policy objectives to overcome these challenges (if any), and identify CMP 
regulatory interventions to meet the objectives. The regulatory interventions which best address 
the policy objectives, based on the analysis carried out and the feedback provided by stakeholders 
during the survey78, are further examined in the impact assessment.  

5.2  Area of improvement: Definition of contractually congested points 

5.2.1  Challenges and shortcomings 

The CMPs are designed to tackle contractual congestion, and in particular cases where capacity has 
been  booked  but  unused.  To  resolve  physical  congestion,  the  TSOs  must  apply  other  measures 
(e.g., interrupt interruptible capacity, plan for system enhancements, etc.). 

The  terms  “physical  congestion”  and  “contractual  congestion”  have  been  defined  in  Regulation 
715/2009 (almost the same definitions carried over to Regulation (EU) 2024/1789). However, as 
discussed in Section 2.1, the Regulation’s definition covers all cases where there is unmet demand 
for firm capacity at the capacity auctions. This results in cases where physically congested network 
points are identified as contractually congested. The CMP Guidelines should make a clear distinction 
between physical and contractual congestion, to ensure that the CMPs are applied in a consistent 
manner at all network points within its scope.  

Alternative options in defining contractual congestion should be considered, to discern them 
from situations of physical congestion, in which the activation of CMPs might not be resolutive. 
In particular, clarity could be given in the provisions of the Guidelines on the cases of contractually 
congested IP to which the CMPs should apply.   

Furthermore, the criterion of non-offer of firm capacity for a period of at least a month, foreseen in 
Point 2.2.3(1) of the Guidelines, may lead to characterizing as congested IPs at which capacity was 
not offered for reasons other than congestion. For example, in 2017 IP Tarvisio (IT) / Arnoldstein 

78 The results of the survey on the implementation of CMPs are presented in Annex V. 

56 

            
       
 
 
 
(AT) exit was classified, in accordance with the Guideline’s criteria, as congested due to the non-
offer  of  capacity,  although  the  unavailability  of  firm  capacity  was  a  result  of  construction  and 
maintenance, and not because of contractual congestion. ACER’s Congestion Reports also include 
some  other  cases  of  IP  sides  that  were  identified  as  congested  due  to  non-offer  of  capacity. 
Indicatively79, at IPs Negru Voda II, III (RO) / Kardam (BG) entry and exit, Bulgartransgaz did not 
offer  capacity  at  due  to  the  lack  of  an  interconnection  agreement  with  Transgaz.  Also,  at  RC 
Thayngen-Fallentor,  terranets  does  not  offer  capacity  because  it  is  used  as  an  emergency  point 
feeding a regional grid and not as a commercial IP.    

The  criteria  for  identifying  congested  network  points  should  be  re-examined,  to  ensure 
that only the points that actually face contractual congestion issues are considered when 
establishing measures to address congestion.  

The criteria of Point 2.2.3(1) of the Guidelines assess congestion only at points with physical flow, 
considering  firm  capacity.  This  excludes  the  potential  contractual  congestion  at  IPs  where 
interruptible virtual reverse flow (VRF) is applied. However, at a couple of IPs, auction premia were 
observed for backhaul capacity over the past the past 3 years. Specifically, premia were observed 
for quarterly and monthly interruptible products of the VRF IP Nea Mesimvria exit (DESFA) and for 
yearly, quarterly and monthly products of Obergailbach (FR) / Medelsheim (DE). Daily premia were 
also observed at other IPs with VRF as well. Although the capacity at the IPs with virtual flows is, 
by  definition,  interruptible,  it  serves  as  the  only  possible  way  to  use  (virtually)  capacity  in  the 
particular direction. If all offered interruptible capacity at the virtual direction of the IP is sold out, 
then other network users would not have the possibility to use any booked but unused capacity. 
From this point of view, the possibility of expanding the criteria of contractual congestion 
to  cover  the  cases  of  IPs  with  interruptible  virtual  reverse  flow  capacity  could  be 
considered. 

5.2.2  Policy objectives 

The  general  aim  for  this  area  of  improvement  is  to  ensure  that  the  network  points  identified  as 
contractually congested reflect the cases in which booked capacity is not being used, obstructing 
other network users from accessing the particular point. The involved stakeholders (ACER, NRAs, 
TSOs) should examine the network points, to ensure that points for which capacity is not available 
for  reasons  other  than  congestion  are  not  identified  as  contractually  congested.  The  policy 
objectives to address the challenges and shortcomings discussed in the previous section entail: 

•  Revision of the definition of contractual congestion, to distinguish between physical and 

contractual congestion. 

• 

Establishment  of  a  criterion  for  non-offering  of  capacity  that  includes  only  cases  of 
contractual congestion. 

•  Application of measures to manage congestion at the IPs with virtual reverse flows. 

5.2.3  Regulatory interventions 

Definition of contractual congestion 

The definition of contractual congestion should avoid, to the extent possible, overlaps with physical 
congestion.  Even  if  a  network  point  is  physically  congested  at  certain  periods  of  time,  the 
underutilization of capacity for multiple days of a year should signal the need for measures to tackle 
undue limitations to accessing firm capacity. As shown in the figure below, the use of capacity at a 

79 Annex of 11th ACER Report on contractual congestion in EU gas markets (link). 

57 

            
       
 
 
 
network point can be indicated in different levels, which provide a different understanding of the 
extent to which the point is in fact contractually congested. 

Figure 23: Extent at which capacity use at a network point 

The inclusion of all the above levels in the definition of contractual congestion builds a definition 
that better reflects the cases where requests of network users to use a network point cannot be 
accommodated even though there is technical capacity available. At the same time, however, the 
complexity of identifying such network points increases. 

The  following  two  formulations  defining  contractual  congestion,  with  different  detailing  of  the 
congestion situation at the network points, could be considered as alternative options of regulatory 
interventions:   

1.  A  definition  that  includes  the  network  points  with  fully  booked  but  unused  firm 
capacity.  In  this  case,  congestion  is  linked  with  the  utilization  of  the  point,  without 
examining whether the market is actually seeking to use this capacity. 

2.  A  definition  that  includes  the  network  points  with  fully  booked  but  unused  firm 
capacity and with unmet demand of network users for firm capacity. In this case, 
congestion focuses on points at which there is actual interest by market participants to use 
the remaining capacity in a firm quality. Unmet demand for capacity could be indicated by 
identifying auctions with demand for capacity exceeding the one offered by the TSO. 

The criteria for each of the above definitions could apply at a network point for a short or prolonged 
period. A specific timeframe should be established, setting the threshold beyond which the point 
shall  be  deemed  as  contractually  congested.  For  example,  a  minimum  period  of  3  months, 
corresponding to the criterion of point 2.2.3.(1).(a) of the CMP Guidelines80, could be considered 
as  a  possible  threshold.  Such  a  timeframe  should  be  determined  in  consultation  with  key 
stakeholders,  to  ensure  that  it  can  adequately  reflect  a  congestion  situation  that  should  be 
addressed with the activation of measures.  

When assessing the congestion criteria at a network point, the involved stakeholders (ACER, NRAs, 
TSOs) should take into consideration the outcomes of the capacity allocation process. Relying solely 
on the occurrence of auction premia in the auctions for firm capacity cannot be a sufficient indication 
of contractual congestion, as premia may occur even if not all firm capacity is eventually allocated 
at the end of the process81. For this reason, a network point should be considered as fully booked 
if firm capacity has been sold out or not offered82, for the examined capacity products. A case-by-
case  verification  of  the  congestion  situation  at  each  network  point  should  thus  be  performed,  to 
ensure that the unavailability of capacity is associated with contractual congestion.  

80 This criterion is used to indicate as contractually congested the IPs at which, during the auctions for primary capacity, 

demand for firm capacity exceeded offer, at the reserve price, for at least 3 monthly products. 

81 This issue has been highlighted by ACER in its proposals for amending CAM NC in the justification provided for amending 

paragraph 1 of Article 32 (Annex II of Recommendation 02/2024). 

82 For a network point to be contractually congested, non-offering of capacity by a TSO should be because all capacity has  

already been sold out in previous auctions. This is discussed as a separate intervention below. 

58 

            
       
 
 
 
 
The stakeholders responding to the survey have shown a clear preference for option (2) of the 
definitions, which examines both the use of firm capacity and the other users’ interest in 
this capacity. As this definition provides a more accurate description of contractual congestion, it 
will be further examined in the impact assessment.  

Criterion for non-offering of capacity 

Although ACER’s Congestion Report already includes comments from TSOs and NRAs on the results 
of the congestion analysis for the corresponding IPs, often concerning the reasons for not offering 
capacity at an IP. To address the examined policy objective, the reasons for not offering capacity 
should be taken into consideration when the congestion status of the IP is defined.  

The TSOs should be required to specify the reasons for which capacity was not offered at the IP, 
and in particular whether these reasons relate to the contracting of firm capacity. These reasons, 
and eventually the identification of the IP as congested, can then be verified by the NRA. To ensure 
transparency, the reasons why that capacity was not offered should be published by the TSOs. This 
information should also be considered by ACER when preparing its Congestion Report.  

The  importance  of  examining  the  reasons  that  capacity  was  not  offered  at  an  IP,  before 
characterising  it  as  congested,  was  verified  by  the  stakeholders’  responses  in  the  survey.  This 
regulatory intervention is further examined in the impact assessment. 

CMPs for IPs with virtual reverse flows 

The implementation of measures to manage contractual congestion at IPs with virtual reverse flow 
would require expanding the CMP Guidelines, in order to cover such network points. This could be 
achieved  either  by  obliging  the  TSOs  to  implement  the  same  CMPs,  as  with  any  other  IP  (more 
interventionist approach), or by requiring the TSOs to determine the measures needed to manage 
congestion at the particular network points (less intrusive approach).   

Both of these options would contradict a key principle of the CMP Guidelines, i.e. that contractual 
congestion  concerns  only  capacity  of  firm  quality  and  does  not  apply  in  cases  of  interruptible 
capacity.  Furthermore,  the  actual  incidents  of  unmet  demand  for  capacity  at  VRF  IPs  have  been 
very few and the application of obligatory measures at an EU level would have very limited added 
value. These have been verified from the responses to the survey, with the majority of stakeholders 
responding that there is no benefit in expanding the definition of contractual congestion to network 
points with virtual flows. Consequently, this regulatory intervention is not examined in the 
impact assessment.  

It  should  be  noted  that  even  if  there  are  no  EU-wide  rules  and  requirements  for  managing 
congestion at VRF IPs, NRAs could still take measures to address any issues of booked but unused 
capacity.  

Overview of regulatory interventions 

The  figure  below  shows  the  regulatory  interventions  examined  for  the  definition  of  contractually 
congested  network  points  and  indicates  the  interventions  to  be  further  examined  in  the  impact 
assessment. 

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Figure 24: Regulatory interventions for the definition of contractually congested points 

5.3  Area of improvement: Scope of the CMPs 

5.3.1  Challenges and shortcomings 

The CMP Guidelines apply to IPs between Member States and to IPs within a Member State (in so 
far as the points are subject to booking procedures), while currently the NRA may decide to apply 
them  to  cross-border  points  with  third  countries83.  Other  types  of  network  points  such  as 
entries/exits to LNG terminals and UGSs, exits to consumption, etc, are not within the scope of the 
Guidelines.  

Some  NRAs  have  opted  to  apply  CMPs,  especially  surrender  and  use-it-or-lose-it  mechanisms  at 
interfaces  of  the  transmission  system  with  LNG  terminals  and  UGSs,  to  facilitate  and  optimize 
utilization at these points. However, the establishment of CMP rules at such points may not always 
be compatible to the national rules for network access. For example, in some countries, capacity at 
the entry point from the LNG terminals is bundled with regasification capacity, and capacity at the 
entry/exit with the UGS is booked by the SSO, thus making the use for CMPs unnecessary or even 
not applicable. Furthermore, most TSOs do not apply CMPs at off-takes to final consumers as the 
booking of capacity is linked to the delivery of gas to the consumer. Consequently, the application 
of  CMPs  at  transmission  network  points  other  than  interconnections  could  be  left  to 
national regulations. 

Some TSOs apply CMPs at their side of IPs with neighbouring third countries. Usually these apply 
unilaterally, without coordination with the operator of the adjacent system. In case the neighbouring 
country  is  an  Energy  Community  Contracting  Party,  then  the  adjacent  TSO  also  has  the 
responsibility to apply CMP rules. In other cases, however, there is no obligation on the neighbouring 
operator  to  conform  with any  rules to  manage  congestion.  In  this  respect, the  TSO  coordination 
should be handled on a case-by-case basis.  

83 After August 2026 the default option at cross-border points with third countries will be the application of the CMP Guidelines 
(Recital (95) of the recast Gas Regulation). The NRA will have the possibility to apply a derogation, for a limited time, from 
applying the mechanisms at these network points. 

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The CMP Guidelines do not apply to LNG terminals and UGSs. Nevertheless, as discussed in Section 
3.5.1, measures to manage congestion and capacity underutilization apply at the LNG terminals. 
Establishment of common CMP rules at LNG terminals is not possible under the current setup, since 
the European framework does not require any uniformity in the services and products that terminal 
operators  provide.  As  a  result,  the  congestion  measures  are  differently  implemented  at  each 
Member State (and sometimes even at different terminals within the same Member State). At many 
terminals  the  operators  can  act  unilaterally  to  release  unused  capacity  of  terminal  users  under 
predefined conditions (e.g., UIOLI or UIOSI mechanisms), while at other terminals it is only up to 
the users to decide whether to dispose of unused capacity, by surrendering it or selling it at the 
secondary market. The results of the survey on the implementation of CMPs have indicated that the 
congestion management measures driven by the terminal users are the most effective ones, with 
secondary capacity trading being considered as the preferred solution (Figure 25), followed by the 
surrender of capacity. 

However, reliance only on terminal users to return their unused capacity may result in cases where 
terminal slots and regasification and storage capacity are not used in an optimal way, if the users 
holding this capacity are not surrendering or reselling it. To ensure that the terminal operators can 
take  action  to  efficiently  use  their  capacity,  some  additional  requirements  for  terminal 
operators  to  manage  congestion  at  LNG  terminal  could  be  considered,  in  addition  to  the 
existing obligations to offer unused capacity on the primary market and to allow reselling of capacity 
at a secondary market (Article 11 of Regulation (EU) 2024/1789). 

Figure 25: Survey on CMPs - rating the measures for managing congestion at terminals84  

The  application  of  congestion  management  measures  at  underground  storage  facilities  depends 
heavily on the national regulations in place in each Member State. In some cases, the allocation of 
annual or shorter-term capacity and the offering of interruptible capacity limits the possibilities of 
long-term congestion. Where the access to storage is negotiated, the management of congestion 
falls on the SSOs. Consequently, an EU-wide approach in managing congestion at UGSs, even 
by setting high-level requirements to SSOs, cannot effectively apply.  

84 Rating from 1 – 4 with 1 indicating low importance and 4 very strong importance. Average from all responses (except N/A) 

are presented. 

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5.3.2  Policy objectives 

Based  on  the  identified  challenges  and  shortcomings,  the  policy  objective  for  this  area  of 
improvement  is  to  set  obligations  to  terminal  operators  for  establishing  appropriate 
measures to manage congestion at their LNG terminals. 

5.3.3  Regulatory interventions 

Management of congestion at LNG terminals 

Underutilization of capacity at the LNG terminals is managed differently in each Member State, with 
the  application  of  various  measures.  In  some  terminals,  the  users  can  surrender  their  unused 
capacity,  while  in  others  the  operators  can  activate,  under  certain  conditions,  a  UIOLI  or  UIOSI 
mechanism.  

A  harmonized  approach  for  managing  congestion  at  terminals  on  could  be  achieved  at  a  pan-
European level by setting obligations to the operators to establish rules and procedures to manage 
congestion. This can be achieved either by establishing a high-level requirement to the operators 
to apply congestion measures (less intrusive approach), or by putting in place detailed procedures 
to be applied at all terminals (more interventionist approach), similar to the CMPs for IPs. As such, 
there are two alternative regulatory interventions that could be considered:  

1.  Introduction of a high-level obligation to terminal operators for withdrawing booked 

but unused capacity from terminal users.  

2.  Definition  of  detailed  procedures  to  manage  congestion,  to  be  applied  in  a 

harmonized manner across the LNG terminals. 

In alternative (1), the terminal operators will have the flexibility to determine the measure to be 
applied  (a  UIOLI  or  UIOSI  mechanism),  its  mechanics  (activation  criteria,  timing,  amount  and 
duration of capacity withdrawn, etc.) and procedures. They would also have to define the terminal 
services  to  which  the  measures  apply  (regasification,  LNG  storage,  truck  loading,  etc.).  Such 
requirements could be included in the principles of capacity-allocation mechanisms and congestion-
management procedures for LNG terminal included in Article 11 of Regulation (EU) 2024/1789, or 
could be introduced in the CMP Guidelines.  

The  detailed  procedures  developed  according  to  alternative  (2)  cannot  be  developed  only  by 
expanding the scope of the CMP Guidelines, as the nature of using capacity at pipelines and LNG 
terminals is very different. Separate provisions for CMPs at LNG terminals should be developed, and 
either  included  in  the  Guidelines,  or  form  part  of  a  separate  regulation.  Such  provisions  would 
include mechanisms and measures with a similar rationale to those of the CMPs at IPs, such as: 

•  A  long-term  UIOLI  mechanism  that  allows  terminal  operators  to  withdraw,  at  their  own 
initiative  and  based  on  predefined  criteria,  booked  terminal  services  that  a  user  is  not 
planning to use (e.g., based on the terminal’s annual schedule) or has been underutilizing.  

•  A short-term UIOLI mechanism that focuses on the withdrawal of unused delivery slots by 

the terminal users. 

•  A  capacity  surrender  procedure  that  harmonizes  at  least  the  key  elements  of  the 

mechanism. 

An oversubscription and buy-back mechanism could also be considered, for some of the services 
offered by the terminal operator. Such a mechanism, however, is not fitting for services that may 
result in the refusal of LNG cargoes, as these create uncertainties that can disincentivise market 
participants from using the LNG facilities.  

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The responses to the survey did not indicate a clear preference for the management of congestion 
at the LNG terminals. To examine if there is merit to consider setting obligations to the terminal 
operators, the impact of both alternative interventions (1) and (2) is further assessed. 

Overview of regulatory interventions 

The figure below shows the regulatory interventions examined for the application of measures to 
manage congestion at the LNG terminals, which will be further examined in the impact assessment. 

Figure 26: Regulatory interventions for managing congestion at the LNG terminals 

5.4  Area of improvement: Establishment of measures to manage congestion 

5.4.1  Challenges and shortcomings 

The  CMP  Guidelines  link  the  establishment  of  CMPs,  and  in  particular  the  decision  of  NRAs  on 
whether  to  apply  FDA  UIOLI,  with  the  identification  of  network  points  as  congested  in  ACER’s 
monitoring report. The report has been published annually and with entry into force of Regulation 
(EU) 2024/1789 will be published every two years. 

In practice, some NRAs use ACER’s report and analysis for information purposes on the congested 
IPs but have decided to apply the CMP to more network points than those identified by ACER. For 
example, the German and Austrian TSOs apply the FDA-UIOLI mechanism at all IPs and not only 
at the congested ones. Other NRAs (e.g., the Czech Republic and Italy) have established network 
access rules that require the TSOs to monitor the Guidelines’ congestion criteria at their IPs, and to 
activate the FDA UIOLI mechanism in case these criteria are fulfilled. On the other hand, in Hungary, 
Poland  and  Slovenia  the  NRAs  monitor  the  ACER  reports  before  requiring  the  respective  TSO  to 
activate the FDA UIOLI renomination restrictions.  

Although the identification of congested IP sides by ACER on the basis of specific criteria provides 
a consistent view of the congestion situation across the EU, reliance on the, now biannual, reporting 
to decide on whether to activate the CMP mechanism could delay the measures needed to efficiently 
address  contractual  congestion.  The  decision  making  on  the  establishment  of  CMPs in  the 
Guidelines  could  be  differentiated  from  the  results  of  ACER’s  reports,  so  that  NRAs  are 
called  to  decide  on  activating  the  CMPs  in  an  expedite  manner,  when  necessary.  All  the  data 
necessary for decision making can be made available to the NRA by the TSO. ACER’s Congestion 
Reports  can  either  be  used  by  the  NRAs  as  a  supplementary  tool  for  monitoring  the  congestion 
situation  at  their  IPs  or  provide  a  source  of  congestion  data  on  an  EU-wide  scale,  used  for 
information purposes. 

When called to select between FDA UIOLI and OS+BB, the NRAs have to take into consideration 
the pros and cons of each option: 

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• 

• 

The FDA UIOLI is an ex-ante measure that has a direct impact on the day-to-day utilization 
of the transmission system by the network users. 

The OS+BB can pose a risk for the TSO, leading to additional costs, in case it is applied to 
IPs that are physically congested. 

Both the FDA UIOLI and the OS+BB mechanisms impact the quality of the firm capacity sold by the 
TSO. The FDA UIOLI treats the renominated volumes beyond the threshold as interruptible capacity. 
The buy-back mechanism may require all network users to release capacity on a pro rata basis, in 
case no-one is willing to sell back their capacity rights. 

So far, the NRAs have not changed their initial choice of mechanism and have continued to apply 
the same mechanism at each IP. Feedback from the interviewed stakeholders indicates that: 

•  No  concerns  or  complaints  from  network  users  were  reported  relating  to  the  restrictions 

resulting from the application of the FDA UIOLI mechanism. 

• 

• 

The TSOs did not have to buy back significant amounts of oversubscribed capacity. 

TSOs that oversubscribe capacity many times prefer to offer it during periods that utilization 
of the network point is limited, to avoid buy-back risks. 

Although  some  NRAs  opted  to  apply  the  OS+BB  mechanism  at  congested  IPs,  to  meet  their 
obligations under the CMP Guidelines, in practice the TSOs do not offer additional capacity. Instead, 
they  prefer  to  resolve  the  congestion  through  market-based  mechanisms,  which  they  consider 
sufficient  (e.g.,  Denmark,  Belgium).  Often  in  Member  States  where  FDA  UIOLI  or  OS+BB  are 
applied, the TSOs combine them with market measures to optimize the use of their network. For 
example, in Germany TSOs rely on both FDA UIOLI and over-nominations, while in France offering 
of  additional  capacity  is  complementary  to  the  application  of  the  use-it-and-buy-it  (UBI) 
mechanism.  The  results  of  the  survey  on  the  implementation  of  CMPs  have  highlighted  the 
importance of market-based measures in managing congestion in practice (Figure 27). 

Figure 27: Survey on CMPs - rating the measures for managing congestion at network points85 

85 Rating from 1 – 4 with 1 indicating low importance and 4 very strong importance. Average from all responses (except N/A) 

are presented. 

64 

            
       
 
 
 
 
To  adapt  to  the  particular  needs  and  characteristics  of  their  gas  market,  the  NRAs  could  be 
allowed more flexibility when deciding which mechanisms to establish in order to manage 
day-to-day contractual congestion. Apart from the choice between the FDA UIOLI and OS+BB 
mechanisms, market-based measures could also be applied, provided that the NRA ensures that 
potential cases of contractual congestions can be effectively and efficiently assessed.  

Market-based measures and application of OS+BB or FDA UIOLI mechanisms aim to address short-
term contractual congestion. The LT UIOLI mechanism should continue to be in place in all 
Member States, as a last resort measure to cope with congestion at long-term capacity products 
and capacity hoarding. 

Regulation 2022/2576 introduced a temporary UIOLI procedure, seeking to manage occurrences of 
monthly contractual congestion. This measure is no longer in place, and the NRAs across the EU 
opted not to apply it when the Regulation was in force. Nevertheless, the existing UIOLI mechanisms 
allow  withdrawal  of  capacity  either  on  a  long-term  or  a  short-term  basis.  Introduction  of  a  new 
UIOLI  procedure,  focusing  on  capacity  with  mid-term  duration  could  be  considered,  to 
give  to  the  TSOs  the  possibility  to  swiftly  take  action  in  cases  where  monthly  and/or  quarterly 
capacity is being underutilized. 

5.4.2  Policy objectives 

This  area  of  improvement  aims  at  ensuring  that  the  mechanisms  applied  to  manage  contractual 
congestion by each TSO are fit to cover the needs, characteristics and specificities of the particular 
gas system and market area. Considering the current practices, such mechanisms could concern 
both CMPs and market measures. The policy objectives to address the challenges and shortcomings 
for this area of improvement, as discussed in the previous section, entail: 

•  Reduce  the  reliance  of  the  activation  of  FDA  UIOLI  from  the  outcomes  of  ACER’s 

Congestion Report. 

• 

Enhancing the NRAs’ flexibility to apply the appropriate mechanisms (CMPs and/or 
market measures) to address short-term congestion in their market. 

•  Management of congestion relating to the use of mid-term capacity products. 

5.4.3  Regulatory interventions 

Activation of FDA UIOLI 

The NRAs’ decision to activate an FDA UIOLI mechanism at an IP should consider recent information 
regarding  the  contractual  congestion  situation  at  the  network  point.  This  ensures  the  timely 
application  of  the  mechanism  if  a  new  congestion  emerges,  as  well  as  the  possibility  to  swiftly 
postpone or terminate the mechanism in case the IP is no longer contractually congested. Decision 
making  by  the  NRAs  on  the  basis  of  the  annual  Congestion  Report  by  ACER  could  create  a  lag 
between the occurrence of congestion, its identification and activation of the FDA UIOLI. With the 
extension of the Congestion Report to biannual, this time gap will increase further.  

The results of the survey indicate that most stakeholders consider that the final decisions for the 
FDA UIOLI should be taken by the NRAs. ACER’s report can serve as a monitoring tool, especially 
for the EU-wide situation of congestion, but its results should not be the basis for the activation of 
the mechanism. 

The trigger for the use of the FDA UIOLI mechanism should be adjusted, to facilitate prompt decision 
making by the NRAs. Two options could be considered at potential regulatory interventions, with a 
different role of ACER’s Congestion Report:  

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1.  ACER’s biannual Congestion Report remains the main trigger for the activation of FDA 
UIOLI. NRAs may carry out their own interim assessments of the congestion situation and 
take them into consideration to apply the mechanism. 

2.  The  NRAs  must monitor  the  congestion  situation  at  the  IPs  and  activate  the  FDA 
UIOLI when needed based on their own assessment. ACER’s biannual Congestion Report 
will no longer be used for decision making and will be used as an informative publication 
analysing congestion at an EU-wide level.  

Some NRAs have opted to apply the FDA UIOLI mechanism at all the IPs of their gas system, and 
therefore their decisions on where to apply the mechanism are not driven by the results of ACER’s 
Congestion Report. Introducing such an approach in the CMP Guidelines, i.e. setting an obligation 
to apply the FDA UIOLI mechanism at all IPs, regardless of their congestion status, would decrease 
the NRAs’ possibilities to decide on the measures they can apply to manage congestion. Imposing 
this obligation would be an intrusive option, that could affect the decision of the NRAs to use the 
FDA UIOLI mechanism and is thus not examined as a potential regulatory intervention. 

Application of appropriate mechanisms 

Market measures to increase access to booked but unused capacity can act complementarily to the 
application  of  CMPs  that manage  short-term  congestion.  Depending on the market  situation  and 
characteristics, many Member States are relying on a combination of market measures and CMPs 
(OS+BB  or  FDA  UIOLI)  to  maximize  the  availability  of  firm  capacity,  while  others  are  managing 
congestion solely through market measures (Figure 28). In the latter cases, the national regulations 
include provisions for the establishment of an OS+BB mechanism, to meet the obligations set by 
the CMP Guidelines, without using mechanisms to oversubscribe capacity in practice.    

Figure 28: Application of CMPs to manage short-term congestion (past 3 gas years) 

The results of the survey validated the importance of combining market measures and CMPs and 
highlighted the role of NRAs in promoting market-based measures. Application of market measures 
should be used as a priority, considering their preventive nature and being less intrusive than CMPs. 
The role of market measures should be emphasised in the CMP Guidelines. Furthermore, the actual 
use of CMPs to manage short-term congestion, i.e. the fact that in practice several TSOs are not 
using any CMP to release capacity, should be taken into account in the Guidelines.  

The  regulatory  interventions  examined  seek  to  ensure  that  the  appropriate  mechanisms  apply, 
fitting  to  the  context  and  specificities  of  each  market.  Two  alternative  options,  with  different 
obligations for using CMPs, are considered:   

1.  Setting  an  obligation  for  the  NRAs  to  ensure  that  market-based  measures  are 

applied to manage contractual congestion, in combination with the use of CMPs. 

2.  Requiring  NRAs  to  apply market-based  measures,  and  to  opt  for  the  activation  of 

CMPs if needed, in case the market measures are not sufficient.  

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Option (1) maintains the current obligatory status of CMPs, with either OS+BB or FDA UIOLI being 
established in the national regulations. On the other hand, in option (2) the application of these 
CMPs in not mandatory. Instead, they are to be used as safeguard measures, which can be activated 
if proactive market measures are not expected to resolve contractual congestion in a satisfactory 
manner.  

The  obligations  set  by  option  (1)  are  practically  already  in  place,  since  NRAs  must  monitor  the 
activities  of  the  TSOs  relating  to  market  measures,  e.g.,  the  offering  of  interruptible  capacity, 
operation  of  the  secondary  capacity  market,  etc.  Consequently,  the  application  of  such  an 
intervention would have no actual added value and is not examined further. Option (2), which 
seeks to combine market measures with the potential use of CMPs in line with the views of 
the surveyed stakeholders, is examined in the impact assessment. 

Implementation of option (2) should include the obligation of the NRAs to consult with the TSOs 
and other stakeholders in order to decide on the best possible solutions for managing congestion. 
Additional publication requirements for the TSOs and/or NRAs should also be introduced (such as 
the  transparency  requirements  discussed  in  Section  5.8),  to  ensure  that  there  is  transparency 
regarding the effectiveness and efficiency of the measures selected. 

Management of congestion for mid-term capacity products 

The  monthly  UIOLI  mechanism  that  was  temporarily  established  with  Article  14  of  Regulation 
2022/2576  sought  to  address  any  congestion  that  concerns  capacity  products  which  are  shorter 
than  yearly  capacity,  but  do  not  require  the  daily  granularity  of  the  FDA  UIOLI  mechanism.  The 
monthly mechanism, however, was not applied in any Member State. Instead, all NRAs relied on 
the CMPs and market measures they already used, as these were sufficient to manage contractual 
congestion situations during the energy crisis or implemented one of the derogatory measures listed 
in paragraph 7 of Article 14. 

The lack of interest of stakeholders to activating a monthly CMP mechanism was validated during 
the  interviews  and  through  their  responses  in  the  survey.  Consequently,  this  regulatory 
intervention will not be examined further. 

Overview of regulatory interventions 

The figure below shows the regulatory interventions examined with respect to the establishment of 
measures to manage contractual congestion and indicates the interventions to be further examined 
in the impact assessment. 

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Figure 29: Regulatory interventions for the establishment of measures to manage congestion 

5.5  Area of improvement: Effectiveness and efficiency of the CMPs 

5.5.1  Challenges and shortcomings 

Some  stakeholders  have  expressed  their  reluctance  to  offer  additional  capacity  through 
oversubscription, due to the risks of having to buy-back this capacity in case of physical congestion. 
As  a  result,  either  the  FDA  UIOLI  was  selected,  or  an  OS+BB  mechanism  is  established  in  the 
Member State but is not used in practice. 

When designing the OS+BB mechanisms, the NRAs can decide on the incentive scheme, allowing 
the TSOs to keep part of the revenues from selling additional capacity, to compensate for the risks 
of having to buy back capacity. However, despite such incentives, even at IPs where the TSOs are 
offering additional capacity, they often do so when utilization of the network is limited, to avoid the 
risks of having to activate the buy-back mechanism, as shown in Section 4.4.3. In these cases, the 
offered oversubscribed capacity is not booked in practice. 

The  effectiveness  of  the  OS+BB  measure  could  be  enhanced  in  case  the  financial 
incentives offered to the TSO are higher. However, the provisions included in the Guidelines 
already  give  enough  freedom  to  the  NRAs  to  decide  on  the  incentive  scheme  to  be  applied. 
Additional incentives could, thus, be introduced with the existing framework, if the NRAs consider 
that increasing the amount of additional capacity offered by the TSO at an IP can add value to the 
efficient use of that point. 

Another issue relating to the effectiveness of the CMPs is the competition between the surrendering 
of capacity and selling it on the secondary market. With the existing network access rules applied 
by  the  TSOs,  a  network  user  cannot  return  its  capacity  rights  to  the  TSO  and  at  the  same  time 
make  this  capacity  available  on  the  secondary  market.  Users  also  show  preference  for  selling 

68 

            
       
 
 
 
capacity on the secondary market (regardless of whether this capacity is liquid or not) instead of 
surrendering it to the TSO. More flexibility could be considered for capacity surrender, with 
network users being allowed to sell it at the secondary market. 

As  discussed  in  Section  3.3.3,  the  CMP  Guidelines  are  flexible  in  the  design  of  the  LT  UIOLI 
mechanism. Key elements, such as the definitions of main terms, activation conditions and amount 
of capacity to be withdrawn, must be defined by each NRA and applied at the respective IPs. This 
can result in the mechanism being applied in an uncoordinated way by adjacent TSOs. Determining 
key  elements  of  the  LT  UIOLI  mechanism  in  more  detail  within  the  Guidelines  could 
increase its effectiveness, as it could be applied consistently by TSOs at both sides of an IP86. 

5.5.2  Policy objectives 

This  area  of  improvement  aims  at  enhancing  the  effectiveness  and  efficiency  of  the  CMPs,  by 
adjusting elements of their application. Based on the shortcomings and challenges discussed, the 
main issues that could be further improved concern the marketing of surrendered capacity and the 
mechanism for LT UIOLI. The specific policy objectives include: 

•  Reduce the competition between surrender and secondary trading of capacity, by allowing, 
to the extent possible, network users to offer capacity at the secondary market and 
surrender it to the TSO at the same time. 

•  Enhance  the  consistency  of  the  LT  UIOLI  mechanisms  applied  by  the  TSOs,  by 

ensuring that the key elements are designed in the same way. 

5.5.3  Regulatory interventions 

Capacity surrender and secondary trading 

The decision on whether to allow or to prohibit network users to market surrendered capacity in the 
secondary market, must weigh the risks of potentially double-selling this capacity and the benefits 
of providing additional channels to network users to dispose of the amounts of capacity they are 
not  planning  to  use.  Currently  there  are  no  relevant  rules  in  the  provisions  for  the  surrender  of 
capacity in the CMP Guidelines, and this issue is resolved at national level, within the TSO’s network 
access rules.  

Competition  between  surrender  of  capacity  and  secondary  trading  of  capacity  can  be  mitigated 
either by requiring NRAs and TSOs to consult on whether surrendered capacity should be traded in 
their market (less intrusive approach), or by obligating TSOs to access the selling of surrendered 
capacity (more interventionist approach). The following two alternative regulatory interventions can 
be considered:  

1.  NRAs  decide,  following  consultation  with  the  respective  TSOs,  whether  network 

users will be allowed to sell surrendered capacity at the secondary market. 

2.  The  CMP  Guidelines  include  provisions  that  allow  network  users  to  sell  their 

surrendered capacity at the secondary market. 

The responses to the survey have highlighted the risks of double-selling the capacity surrendered 
and traded (including stakeholders in favour of this regulatory intervention). Option (1) allows the 
NRAs and TSOs to jointly decide whether such a possibility will be given to the network users, taking 
into consideration the market conditions and the TSO’s capabilities to avoid cases where the same 
capacity will be sold twice. On the other hand, option (2) is obligatory for all TSOs, exposing them 

86 This is also a harmonization issue, discussed in Section 5.6. 

69 

            
       
 
 
 
to potential overselling of firm capacity, which they would then have to manage. Considering the 
risks of option (2), only option (1) is further examined in the impact assessment.  

Enhancing the consistency of the LT UIOLI mechanisms87 

The consistency of the LT UIOLI mechanisms applied by the TSOs can be enhanced by ensuring 
that the same key elements apply across all IPs. To this end, the existing provisions of the CMP 
Guidelines should be more detailed, to provide clear directions on how the mechanism should 
be designed and applied.  

The survey responses clearly indicated that stakeholders do not consider that further detailing the 
provisions for the LT UIOLI mechanism in the CMP Guidelines would be necessary. Since the entry 
into  force  of  the  CMP  Guidelines,  the  mechanism  has  been  activated  only  a  few  times,  and  its 
importance in managing capacity hoarding is further decreasing with the phasing out of the legacy 
contracts. This intervention is therefore not examined further. 

Overview of regulatory interventions 

The  figure  below  shows  the  regulatory  interventions  examined  to  enhance  the  effectiveness  and 
efficiency of CMPs and indicates the intervention to be further examined in the impact assessment. 

Figure 30: Regulatory interventions for enhancing the effectiveness and efficiency of CMPs 

5.6  Area of improvement: Harmonization of rules between adjacent TSOs 

5.6.1  Challenges and shortcomings 

As presented in Section 3.3, some TSOs and NRAs of adjacent systems have cooperated to follow 
the  same  principles  when  applying  CMPs  at  their  common  IPs.  This  has  been  the  case  between 
Enagás, Teréga and REN for a joint OS+BB, as well as between CREG, ACM and Ofgem for setting 
common principles when applying the LT UIOLI mechanism. 

The analysis carried out has not indicated any specific case of cross-border IPs where the application 
of  different  mechanisms  to  manage  short-term  congestion  (market  measures,  OS+BB  or  FDA 
UIOLI) has resulted in considerable restrictions to the smooth operation of the IP. Nevertheless, 
the responses to the survey on the implementation of CMPs indicate that most stakeholders consider 

87 This issue also relates to the harmonization of rules by adjacent TSOs and is examined in that area of improvement as well 

(Section 5.6). 

70 

            
       
 
 
 
 
that the use of different mechanisms has adverse effects on the use of the IP’s capacity. Although 
the respondents did not indicate specific evidence on IPs where use of capacity was hampered, they 
highlighted potential  issues  in  the  offering  of  bundled  products,  difficulties  and  confusion  for  the 
users  and  inefficient  capacity  allocation.  To  manage  such  issues,  the  introduction  in  the 
Guidelines of some provisions aiming to ensure harmonization of the applied congestion 
measures, could be considered. 

A harmonization issue that was highlighted during the interviews concerned the activation of the LT 
UIOLI mechanism at the VIP Pirineos. As discussed in Section 3.3.3, this was a result of different 
activation criteria applied on the Spanish and French sides of the VIP. 

The  CMP  Guidelines  already  require  coordination  for  the  application  of  the  OS+BB  and  the  FDA 
UIOLI  mechanisms.  To  facilitate  a  harmonized  approach  in  the  framework  applied  for 
activating  the  LT  UIOLI  mechanism,  additional  requirements  could  be  defined  in  the 
Guidelines, especially regarding key elements such as the activation conditions and the procedure 
for triggering the mechanism. 

At cross-border points with third-countries, the interviewed NRAs and TSOs do not appear to seek 
a harmonized application of CMPs, while no issues with managing congestion were reported.  

5.6.2  Policy objectives 

The harmonization of rules to manage congestion between adjacent TSOs can be enhanced either 
by ensuring that the measures applied at the two sides of an IP do not lead to adverse impacts for 
the use of capacity, or by strengthening the consistency of specific CMPs. The policy objectives to 
address the challenges and shortcomings for this area of improvement, as discussed in the previous 
section, entail: 

•  Strengthening the level of harmonization in the mechanisms applied by the TSOs at 

an IP 

• 

Ensuring that at least the key guiding principles and key elements for the design of 
the LT UIOLI are harmonized between neighbouring Member States. 

5.6.3  Regulatory interventions 

Strengthening the harmonization of cross-border measures 

The CMP Guidelines do not restrict the use of different CMPs or market-based measures to manage 
short-term  congestion  at  the  two  sides  of  an  IP.  The  only  means  to  safeguard  that  the  use  of 
capacity is not impacted is the obligation of NRAs to consult with their neighbouring counterparts 
and  take  their  opinions  into  account  before  implementing  an  FDA  UIOLI  mechanism.  These 
consultations  alone  do  not  ensure  that  the  use  of  the  mechanisms  across  the  borders  will  be 
harmonized, and that the use of bundled capacity at the IP will not be adversely affected. They also 
do not cover the cases where solely market-based measures apply at one side of the IP. 

Harmonization  of  the  measures  applied  to  manage  congestion  at  cross-border  IPs  can  be 
strengthened either by ensuring that the NRAs will take action if it has been established that the 
use of different measures is restricting the use of capacity (less intrusive approach), or by obliging 
the adjacent TSOs to agree on the application of the same measure (more interventionist approach). 
The following two alternative regulatory interventions can be considered:  

1.  Adjacent  NRAs  monitor  the  use  of  capacity  at  the  IP  and  undertake  proactive  or 
mitigating actions if needed, in case it has been established that the existing measures 
cause undue restrictions to the access to and use of the IP. 

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2.  Adjacent  TSOs  must  consult  with  each  other  and  agree  on  common  measures  to 
manage  congestion,  to  be  applied  at  both  sides  of  the  IP.  The  respective  NRAs  must 
approve the agreed measures. 

Alternative option (2) would require major revisions in the CMPs currently applied at cross-border 
IPs, and consultations between most adjacent TSOs. On the other hand, the results of the interviews 
and survey with stakeholders have not provided any evidence of specific cases where the use of an 
IP was affected by the application of different measures. Therefore, obliging TSOs to align in the 
measures  they  apply  could  distort  the  current  operations  without  showing  a  clear  benefit.  Only 
option (1), which is  a less interventionist intervention, will be examined further in the 
impact assessment. 

Harmonization of rules for LT UIOLI mechanism 

The CMP Guidelines are flexible in the design of the LT UIOLI mechanism. As a result, key elements 
(e.g.,  definitions,  activation  conditions,  amount  of  capacity  to  be  withdrawn)  of  the  mechanism 
applied at the two sides of an IP must be defined by the adjacent NRAs. Harmonization of the LT 
UIOLI  mechanisms  applied  at  an  IP  can  be  achieved  either  by  ensuring  coordination  between 
adjacent NRAs (less intrusive approach), or by developing detailed rules for the application of the 
LT UIOLI mechanism, to be applied by all TSOs (more interventionist approach). The following two 
alternative regulatory interventions can be considered:  

1.  Adjacent NRAs must coordinate, in order to define key elements of the LT UIOLI 

mechanism, such as its activation conditions. 

2.  The existing provisions of the CMP Guidelines are further detailed, to provide clear 

directions on how the mechanism should be designed and applied88. 

As  already  discussed  in  Section  5.5.3,  most  surveyed  stakeholders  are  not  in  favour  of  further 
detailing  the  LT  UIOLI  mechanism  in  the  CMP  Guidelines.  The  survey  has  also  indicated  that 
stakeholders do not see an added value in requiring adjacent NRAs to consult in order to apply a 
harmonized LT UIOLI mechanism. Considering the lack of interest by the stakeholders, and the fact 
that the need to manage long-term capacity is decreasing with the phasing out of legacy contracts, 
neither of the options above is examined further. 

Overview of regulatory interventions 

The  figure  below  shows  the  regulatory  interventions  examined  to  strengthen  the  cross-border 
harmonization  of  the  congestion  management  measures  applied  at  the  two  sides  of  an  IP  and 
indicates the intervention to be further examined in the impact assessment. 

88 This regulatory intervention was also discussed as an intervention to improve the effectiveness and efficiency of CMPs 

(Section 7.5).  

72 

            
       
 
 
 
Figure 31: Regulatory interventions for strengthening cross-border harmonization 

5.7  Area of improvement: Management of congestion revenues 

The use of congestion revenues, deriving from the unmet demand at capacity auctions, is described 
in the tariff regulations of the Member States, either with dedicated provisions or treated as part of 
the TSO’s overall regulated revenues.  

Some  NRAs  have  established  specific  rules  for treating the  revenues of  reallocated  capacity  that 
was released through CMPs. For example, this may include non-payment of auction premia to the 
network  user  having  its  capacity  released,  or  recovery  of  any  negative  difference  between  the 
network charges for the reallocated capacity and those for the capacity originally sold. 

The  congestion  revenues  may  either  be  returned  to  the  network  users  by  decreasing  future 
transmission  tariffs,  or  be  used  by  the  TSO  for  future  investments,  especially  for  upgrading 
physically  congested  network  points.  Interviews  with  the  NRAs  have  indicated  that  usually  the 
revenues are returned to the systems as future decreases in network charges. 

The  approach  followed  for  using  the  congestion  revenues  is  country-specific  and  defined  in  the 
national  regulatory  framework.  It  does  not  appear  necessary  to  establish  new  EU-wide 
provisions relating to the use of congestion revenues collected by the TSO. 

5.8  Area of improvement: Transparency 

5.8.1  Challenges and shortcomings 

All information necessary to monitor the application of CMPs and to examine their effectiveness and 
efficiency is collected by the TSOs. Some information is published, and some reported internally to 
the NRA (either periodically or upon the NRA’s request). 

As already described in Section 4.5, there are data inconsistencies between the data published at 
the  TSOs’  websites  and  at  ENTSOG’s  TP,  as  well  as  cases  where  data  is  not  reported  at  the 
transparency platform. There is also information reported by the TSOs (and/or at ENTSOG’s TP) as 
application of CMPs that is sometimes not related to the release of capacity to manage contractual 
congestion. This may lead to an overestimation of the activation of CMPs. For example: 

73 

            
       
 
 
 
• 

• 

In Hungary, the LT UIOLI mechanism was used to release capacity from network users that 
went  bankrupt,  because no  other  mechanism  to  terminate  their  contract  was possible  at 
that time (this issue has now been addressed).  

In Germany, the OS+BB mechanism was used to offer additional firm capacity during the 
market merger in order to avoid offering most capacity as interruptible. Indicatively, around 
80% of the firm capacity offered by OGE was oversubscribed. 

Currently only a few TSOs publish information at their transparency portals concerning the amount 
of  daily  released  capacity  that  has  been  reallocated.  Such  information  could  be  published  by  all 
TSOs  that  apply  the  CMPs,  to  better  inform  the  network  users  on  how  effectively  congestion  is 
managed. 

The responses to the survey on the implementation of CMPs have indicated that information relating 
to CMPs contributes to the network users’ decision making when planning for the use of capacity. 
Of particular importance is the availability of information on the amount of capacity released through 
CMPs, and the amount of reallocated capacity (Figure 32). Additional information on the use of the 
OS+BB mechanism could also be published. This relates to information on the additional capacity 
they are offering and booked at each IP (even if it is zero). 

Figure 32: Survey on CMPs - rating the impact of CMP data on the users’ decision making 

The  obligations  of  the  TSOs  relating  to  the  publication  and  transparency  of  the  CMPs’ 
application  could  be  further  detailed,  to  ensure  consistency  and  enhance  the  amount  of 
information provided to the network users. 

5.8.2  Policy objectives 

Based  on  the  identified  challenges  and  shortcomings,  the  policy  objective  for  this  area  of 
improvement is to improve the information published by the TSOs relating to CMPs. 

5.8.3  Regulatory interventions 

Improvement of published CMP information 

Transparency on the use of CMPs can be enhanced both by improving the quality of the type of 
information already published, and increasing the amount of information made available.  

74 

            
       
 
 
 
The  shortcomings  relating  to  the  quality  and  clarity  of  information,  discussed  above,  can  be 
addressed by further clarifying the information obligations of the TSOs. Currently, Regulation (EU) 
2024/178989 requires TSOs to publish, in near real time, the “total capacity made available through 
the application of the congestion-management procedures […] per applied congestion-management 
procedure”. To ensure that the information published is consistent and specific to CMPs, issues such 
as the following should be addressed: 

• 

• 

• 

The capacity made available through the application of CMPs published by the TSOs should 
concern  only  the  cases  where  the  mechanisms  were  activated  to  manage  contractual 
congestion. Capacity releases by using the CMP mechanisms for other purposes should be 
clear and distinct. 

The phrase “capacity made available through the application of the congestion-management 
procedures”  should  be  specifically  elaborated  for  each  CMP.  For  example,  in  the  case  of 
OS+BB  it  should  be  clear  that  the  information  to  be  published  refers  to  the  amount  of 
additional capacity that was offered by the TSO, and not the capacity that was bought by 
the TSO after activating a buy-back procedure. 

The  data  published  by  the  TSOs  in  their  websites  should  be  consistent  with  the  data 
published in the ENTSOG transparency platform. 

Additional  information  can  be  published,  to  improve  the  network  users’  decision  making  when 
planning their capacity needs. The responses to the survey have indicated that the most important 
information that is currently not published by many TSOs concerns the amount of released capacity 
that has been reallocated to other network users. Other types of information that could be published 
can concern the amount of additional capacity that was booked by users, and the amount of capacity 
that was bought by TSOs after activating a buy-back procedure. 

Based  on  the  above,  the  following  two  regulatory  interventions  can  be  considered  to  improve 
transparency: 

1.  Provision of clarifications to the TSOs’ publication requirements for the use of CMPs. 

2.  Introduction of new publication requirements for CMP data to the TSOs. 

These interventions are complementary and can jointly contribute to the policy objective. They are 
thus examined together in the impact assessment. 

Overview of regulatory interventions 

The figure below shows the regulatory interventions examined to improve the publication of data 
relating to CMPs and indicates the interventions to be further examined in the impact assessment. 

89 Point 3.3.(1) of Annex I of Regulation (EU) 2024/1789. 

75 

            
       
 
 
 
Figure 33: Regulatory interventions for improving published CMP data 

76 

            
       
 
 
 
 
 
 
6.  Impact assessment of regulatory interventions 

6.1  Overview of the assessment framework 

The  impact  of  each  regulatory  intervention  identified  in  Section  5  is  assessed  using  a  3-step 
analytical  framework:  (1)  estimation  of  the  intervention’s  size  /  magnitude,  (2)  qualitative 
assessment of the intervention’s impact, and (3) rating of the intervention's impact. An overview 
of these steps is provided in the following figure. 

Figure 34: Overview of impact assessment analytical framework 

The “no-policy scenario” reflects the current application of CMPs in the European gas systems. It is 
assumed that the same results will be achieved, with respect to the management of congestion and 
the use of capacity, if there are no regulatory interventions and the TSOs continue to follow the 
same practices and apply the same CMPs. The assessment of the “no-policy scenario” is based on 
the  findings  of  the  desktop  research  on  the  rules,  procedures  and  regulatory  approaches  for 
managing congestion at natural gas infrastructure and the quantitative analysis of the congestion 
network points.  

The criteria used to assess the impact of the regulatory interventions are grouped together on the 
basis  of  the  affected  actors  (NRAs,  TSOs,  network  users).  These  criteria,  presented  in  Table  13, 
focus  on  the  key  areas  of  interest  for  each  actor.  To  ensure  consistency  in  the  analysis,  all  the 
assessed interventions are examined using the same criteria, nevertheless, the analysis focuses on 
those criteria where an impact can be expected. 

Table 13: Criteria for assessing the impact of regulatory interventions 

Actors 

Criteria 

Description 

Regulatory effectiveness 

Whether the regulatory framework can better reflect the 
actual application of the CMPs, avoiding regulatory 
provisions which are not used in practice 

NRAs 

Operational complexity 

Whether the mandate of the NRA has to increase, resulting 
in additional operational and administrative burdens 

Adaptability of regulation 

Whether the regulatory framework becomes more adaptable 
to future changes in the gas market and system (e.g., 
immediate application of CMPs in case of congestion) 

77 

            
       
 
 
 
Efficient use of gas 
systems 

The extent to which gas systems become more efficient, 
with release of additional unused capacity or expediting the 
activation of CMPs 

TSOs  

(or LSOs if the 
intervention 
concerns LNG 
terminals) 

Operational efficiency / 
costs 

Whether the operator’s procedures will improve decreasing 
costs, or whether additional effort is required, increasing 
costs 

Adaptability of 
transmission services 

Whether the services provided by the operator become 
more adaptable in case the gas market or system situation 
changes 

TSO revenues 

Whether the revenues collected by the operator from selling 
capacity may increase or decrease 

Access to the system 

The extent to which access of other network users to the 
system is facilitated, through the release of booked but 
unused capacity 

Efficient decision making 

Whether transparency of information on CMPs is enhanced, 
facilitating decision making by the network users 

Public access to 
information 

Whether information becomes available to the public, 
facilitating its accessibility 

Gas system costs 

Whether the costs for accessing the gas system may 
decrease or decrease with the application of the intervention 

Network 
users  

(and 
subsequently 
final 
customers) 

The examined criteria may concern economic, environmental or social impacts of the intervention. 
The figure below indicates which types of impacts are considered per criterion. 

Figure 35: Types of impact for each assessed criterion 

6.2  Area of improvement: Definition of contractually congested points 

Two regulatory interventions are examined under this area of improvement: 

1.  Change of the definition of contractually congested network points, to include those with 
booked but unused capacity and with firm capacity requests by network users that cannot 
be fulfilled by the TSO. 

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2.  Change  of  the  congestion  criterion  of  ”no  offer”  of  capacity,  to  include  only  the  network 
points  at  which  capacity  was  not  offered  because  it  was  already  sold  out  at  previous 
auctions. 

The impact of each of the above interventions is discussed below. 

6.2.1  Change of the definition of contractually congested network points 

Size of the intervention 

The regulatory intervention will impact the number of IP sides that are considered as contractually 
congested when the definition of the CMP Guidelines is applied by NRAs, TSOs and ACER and other 
stakeholders. The table below presents the number of IPs sides with status of “congested due to 
premia” or “close to be congested” in ACER’s Congestion Reports (applying the existing definition 
of contractual congestion) and the number of IP sides that were congested for at least one month 
in the examined period.  

Table 14: Number of congested IP sides using different definitions of contractual congestion90 

ACER’s Report 

Definition of regulatory intervention91 

Year of analysis 

No of IP sides 
congested due 
to premia 

No of close to 
be congested 
IP sides 

No of IP sides 
congested for 3 
months or more  

No of IP sides 
congested for 1 or 
2 months 

2022 (10th ACER Report) 

2023 (11th ACER Report) 

45 

28 

9 

13 

11 

11 

5 

7 

Using the definition of the regulatory intervention can lead to a significant drop in the number of IP 
sides identified as contractually congested. These IP sides will reflect the cases where, during the 
period of the analysis, there were months in which booked capacity was underutilized and at the 
same there were unmet requests from other network users for firm capacity. 

Analysis of impacts 

The  change  in  the  definition  of  contractually  congested  network  points  that  is  foreseen  in  this 
regulatory intervention will establish a more accurate description of the points where firm capacity 
is available but cannot be used by other market participants. This will facilitate the identification of 
physical and contractual congestion at a network point. Thus, the signals that the NRAs receive  for 
the  implementation  of  CPMs  or  market  measures  to  manage  congestion  will  improve 
considerably, strengthening regulatory efficiency. 

The differentiation between physical and contractual congestion when capacity at a network 
point is fully booked can also make the CMP rules more adaptable to changes in the use of the gas 
system. Activation of CMPs can become more targeted and justified, based on the availability of 
unused technical capacity in the system. 

On the other hand, the analysis and monitoring of the congestion situation at the network 
points by the NRAs may become more complex, as several factors (booking and utilization of 
capacity, capacity demand by network users) have to be considered. As a result, a change in the 
definition  of  contractually  congested  points  could  result  in  slightly  increasing  the  administrative 

90 To make the figures comparable, the examined period is in calendar years. Only the IP sides included in ACER’s reports are 

taken into account in the analysis.  

91 To apply the definition of the regulatory intervention, we used the average monthly utilization rate of the IP side and 

considered unmet demand for yearly, quarterly and monthly products.  

79 

            
       
 
 
 
 
burden for the NRAs. The same applies for the analysis carried out by ACER for the preparation of 
its Congestion Report. 

Revising the way contractual congestion is defined will not result in the TSO releasing more unused 
capacity, compared to the current activation of CMPs. Nevertheless, a definition that excludes the 
situations of physical congestion could help the TSO to  avoid the undue activation of CMPs 
when a network point is operating at its technical limits. The release of booked and unused 
capacity when there are capacity requests from other network users would contribute to the efficient 
use of the gas system. At the same time, from the network users’ point of view, a more accurate 
identification  of  contractual  congestion  can  ensure  that  the  users’  firm  capacity  rights  would 
only be affected if these remain unused, improving the access to the network.   

The transmission services offered by the TSOs, and in particular the management of congestion, 
will  become  more  adaptable  to  the  congestion  situation  at  the  network  points,  better 
justifying  the  release  of  capacity  to  serve  requests  from  other  users.  On  the  other  hand,  the 
intervention  does  not  require  the  TSO  to  apply  new  rules  or  procedures  that  would  affect  its 
operations and result in additional administrative burdens. 

The  information  published  by  the  NRAs  and  TSOs  and  ACER’s  Congestion  Report  can  provide  a 
distinction  between  physical  and  contractual  congestion  at  the  IPs.  This  will  provide  to  network 
users a better understanding of the congestion situation at the IP, contributing to their decision 
making for booking future capacity. 

It is not expected that the application of the regulatory intervention will have a measurable impact 
on the TSO’s revenues and correspondingly to the costs of network users.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 15: Summary of impacts of changing the definition of contractually congested points 

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6.2.2  Change in the criterion of “non-offer” of capacity 

Size of the intervention 

ACER’s Congestion Reports distinguish the IPs that have been identified as congested because no 
capacity was offered for a period of at least a month. As presented in Table 16, comments were 
provided by some TSOs and NRAs, indicating that capacity was not offered at the particular IP for 
reasons other than the capacity already being sold out. The table also shows that the number of 
IPs where capacity was not offered is not correlated to the overall number of congested IPs. This is 
another  indication  that  at  most  IPs  the  reasons  for  not  offering  capacity  are  not  related  to  the 
booking situation at that point. 

Table 16: IP sides identified as congested due to non-offer of capacity in ACER’s reports92 

Year of analysis 

No of 
congested 
IP sides 

No of IP sides 
congested due to 
non-offer of capacity 

No of IP sides with comments 
indicating non-offer not related 
to lack of available capacity 93 

2021 (9th ACER Report) 

2022 (10th ACER Report) 

2022 (11th ACER Report) 

18 

50 

35 

8 

5 

7 

3 

- 

4 

With the implementation of the regulatory intervention, the IP where non-offer of capacity is not 
related to congestion will be determined by the NRAs and TSOs and will be excluded from the points 
identified as congested. The number of IPs that would be impacted will be limited, considering the 
results of ACER’s past reports. Nevertheless, it can be expected that the number of IPs congested 
due to non-offer of capacity will be considerably decreased. 

Analysis of impacts 

Refinement  of  the  congestion  criterion  of  non-offer  of  capacity  would 
improve  the 
characterization of congested IPs, by identifying only the cases where firm capacity was not 
available because previous capacity products were sold out. Determination of the reasons for not 
offering capacity by the TSOs and NRAs, ensures that the actual situation at the IP is appropriately 
depicted, and that the application of measures to manage congestion is justified. 

The NRAs and TSOs are already providing feedback to ACER concerning the results of its Congestion 
Report and may justify (TSO) and validate (NRA) the reasons for which no capacity was offered at 
an IP. Application of this regulatory intervention will not change the requirements of NRAs and TSOs 
with  respect  to  monitoring  and  reporting  on  congestion  and  will  not  result  in  additional 
administrative burdens. 

Even  if  an  IP  point  has  been  formally  identified  as  congested  because  it  meets  the  “non-offer” 
criterion of the Guidelines, the TSO would not release capacity through CMPs if the non-offering of 
capacity  was  for  reasons  other  than  all  capacity  being  sold  out94.  Consequently,  changes  in  the 
definition of non-offer of capacity does not impact the network operation and offered transmission 
services by the TSO and network access by the users.  

Reporting  on  the  reasons  for  which  capacity  was  not  offered  at  an  IP,  and  separating  the  cases 
where  capacity  was  sold  out  and  those  where  the  IP  was  inaccessible  for  other  reasons,  will 

92 Sources: ACER’s 9th – 11th Congestion Report. 

93 The number of IPs with comments does not include the exit IPs Negru Voda II and III of Transgaz, at which capacity is not 

offered due to lack of interconnection agreement with the adjacent TSO. 

94 Except for the TSOs applying FDA UIOLI at all IPs, in which case the congestion criteria of the CMP Guidelines practically  

have no impact. 

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improve the information made publicly available. At the same time, this will provide to the 
network users, a better understanding of the congestion situation at the IP.  

It is not expected that changes in the congestion criterion of “non-offer” of capacity will impact the 
TSO’s revenues and correspondingly the costs of network users.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 17: Summary of impacts of changing the congestion criterion for non-offer of capacity 

6.3  Area of improvement: Scope of the CMPs 

Two alternative regulatory interventions are examined under this area of improvement, focusing on 
the management of congestion at LNG terminals: 

1.  Setting high-level obligations to operators of LNG terminal operators, to establish measures 

that allow them to withdraw booked but unused capacity. 

2.  Establishing detailed rules for managing congestion at LNG terminals. 

The impact of each of the above interventions is discussed below. 

6.3.1  High-level congestion management obligations to LNG terminal operators 

Size of the intervention 

As discussed in Section 3.5.1, many LNG terminals apply congestion management measures that 
allow the terminal operators, under certain conditions, to unilaterally release capacity booked by 
terminal  users  and  make  it  available  in  the  market.  Such  conditions  relate  for  example  to 

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underutilized  terminal  capacity,  or  scheduling  for  the  use  of  booked  capacity.  There  are, 
nevertheless, terminals in a few Member States at which capacity is released only if the terminal 
users surrender it to the operator or sell it to the secondary market. This regulatory intervention 
shall apply at all the European LNG terminals. As a result, the terminal operators that currently rely 
only on the users to make their booked capacity available will have to introduce new measures, 
requiring operators to apply principles such as use-it-or-lose-it or use-it-or-sell-it. 

Analysis of impacts 

Regulatory efficiency will improve with this intervention. The NRAs have already established national 
rules  and  procedures  to  manage  congestion  at  most  LNG  terminals  (usually  UIOLI  or  UIOSI 
mechanisms). Setting an EU-wide high-level obligation for managing congestion at the terminals 
would enhance the harmonization between the national rules and requirements and the 
European regulation.  

In  case  measures  are  not  already  in  place,  implementing  this  intervention  would  increase  the 
administrative burden for both NRAs and terminal operators. At regulated terminals the NRAs, in 
consultation  with  the  terminal  operators,    must  develop  mechanisms  allowing  them  to 
withdraw  the  terminal  users’  capacity.  At  exempted  terminals  the  operators  must  establish  the 
respective  mechanisms.  No  other  rules  relating  to  the  terminal  services  will  have  to  be 
adapted,  as  the  congestion  management  procedures  will  be  tailored  to  the  operation  of  the 
particular terminal.  

Some LNG terminal operators are already applying rules and procedures to withdraw capacity that 
is  underutilized  (or  not  scheduled  to  be  used)  by  the  terminal users.  In  others,  however,  use  of 
available  capacity  is  managed  through  initiatives  of  terminal  users,  surrendering  or  selling  their 
capacity. In the latter case, allowing operators to unilaterally release unused capacity, in 
case demand for using the terminal exceeds the available capacity, can address situations 
where  the  users  were  not  willing  to  return  their  booked  capacity.  This  will  improve  the 
efficient  use  of  the  terminal’s  capacity  and  facilitate  access  of  other  market  participants  to  the 
facility. 

The regulatory intervention sets only high-level requirements, allowing the terminal operators to 
apply a mechanism that has been tailored to the operation of their facility. This flexibility enables 
the unconstrained adjustment of the national regulation, and the corresponding services 
by the terminal operator, to address changes in the market that can affect the use of capacity 
and the need to manage congestion at the LNG terminal.  

Ensuring that operators will have the obligation to apply measures to tackle contractual congestions, 
will  improve  the  predictability  of  the  rules  for  accessing  the  facilities.  Network  users  can 
expect used capacity to be either returned by the users or withdrawn by the terminal operator. This 
will facilitate their decision making for scheduling LNG cargos. 

The regulatory intervention does not result on any additional obligations to the NRAs or terminal 
operators  for  publishing  information  about  the  congestion  situation  at  the  LNG  terminals.  Thus, 
publicly available information will not be affected. 

The application of procedures for withdrawing unused capacity from terminal users is not expected 
to impact TSO’s revenues and correspondingly to the costs of the users. 

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

83 

            
       
 
 
Table 18: Summary of impacts of setting high-level obligations to LNG terminal operators 

6.3.2  Detailed congestion management obligations to LNG terminal operators 

Size of the intervention 

Almost  all  LNG  terminals95  already  have  in  place  measures  to  manage  congestion,  including 
mechanisms of UIOLI, UIOSI, surrender of capacity and OS+BB. With this regulatory intervention, 
the same CMPs should apply across the EU. Consequently, the existing measures should be adjusted 
or even terminated, and the NRAs together with the terminal operators should establish new rules 
that comply with the detailed congestion management obligations. 

Analysis of impacts 

A  new  set  of  rules  would  have  to  be  developed  at  the  LNG  terminals,  in  line  with  the  detailed 
congestion management obligations. These rules would have to apply at terminals with different 
characteristics and rules for allocating and managing capacity. As with the case of CMPs applied at 
IPs, there can be cases of LNG terminals at which congestion management rules will be 
established but not activated. Therefore, imposing the same detailed rules could in some cases 
negatively impact the regulatory effectiveness of the terminals’ operation rules. 

Implementation  of  this  intervention  would  require  significant  effort  from  both  the  NRAs  and  the 
terminal operators. The NRAs have to develop the national framework applying the detailed 
requirements. Other rules relating to the use of capacity may also have to be revised at some 
terminals,  to  ensure  compatibility  with  the  congestion  management  obligations.  The  terminal 
operators will also have to adjust their procedures, processes and IT systems to comply with 
the new requirements.  

95 Only the Portuguese LNG terminal relies on market measures to manage the unused capacity. 

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The intervention foresees the development of detailed rules for managing congestion. This will limit 
the possibilities that the NRAs and the terminal operators will have to adjust these rules 
in case there are considerable changes in the gas market and system that can affect the operation 
of and access to the LNG terminals.  

The  detailed  congestion  management  rules  would  include  both  intrusive  measures  (mechanisms 
allowing  the  terminal  operator  to  unilaterally  withdraw  capacity)  and  proactive  procedures 
(surrender of capacity by users, offering of additional capacity). This combination of measures 
can provide more possibilities to release capacity from terminal users with capacity rights 
and reallocate it to other market participants interested in using the facility. As a result, the use 
of the terminal becomes more efficient, and network access is facilitated.  

The application of specific congestion measures at an LNG terminal will improve the predictability 
of  the  rules  for  accessing  the  facility.  Network  users  can  expect  used  capacity  to  be  either 
returned by the users or withdrawn by the terminal operator. This will facilitate their decision making 
for scheduling LNG cargos. 

The regulatory intervention does not result on any additional obligations to the NRAs or terminal 
operators  for  publishing  information  about  the  congestion  situation  at  the  LNG  terminals.  Thus, 
publicly available information will not be affected. 

The  revenues  of  the  terminal  operators  can  be  impacted  if  additional  capacity,  offered 
through oversubscription, is booked after all capacity at the terminal has been sold out and. 
Taking into consideration the experience from the application of OS+BB at IPs, it can be expected 
that cases where additional capacity is sold will be limited.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 19: Summary of impacts of setting detailed obligations to LNG terminal operators 

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6.4  Area of improvement: Establishment of measures to manage congestion 

The regulatory interventions examined under this area of improvement are the following: 

1.  Two alternative options are considered relating to the triggers for activating the FDA UIOLI 

mechanism: 

i.  Activation using ACER’s Congestion Report and interim assessments of the NRAs on 

the congestion situation at the IPs. 

ii.  Activation based only on NRAs’ assessments on the congestion situation at the IPs. 

2.  Priority to the application of market measures and activation of CMPs, if needed, to fully 

manage contractual congestion. 

The impact of each of the above interventions is discussed below. 

6.4.1  Activation of FDA UIOLI based on either ACER’s or NRAs’ monitoring 

Size of the intervention 

With this intervention, ACER’s Congestion Reports will continue to be used as triggers for FDA UIOLI. 
The NRAs will also have the possibility to activate the mechanism on their own, if they consider that 
this will resolve any identified situations of contractual congestion. This reflects the actual approach 
followed  by  many  TSOs  that  either  trigger  the  mechanism  at  IPs  that  they  have  identified  as 
congested themselves, or apply FDA UIOLI restrictions at all their IPs, regardless of whether these 
have been identified as congested in ACER’s reports. 

The table below provides an overview of the approach followed by the TSOs to activate the FDA 
UIOLI mechanism. Due to the change in the frequency of ACER’s reporting obligations from annual 
to biannual, it is likely that TSOs currently relying on ACER’s findings will revise their mechanisms 
to be able to trigger the CMP based on their own monitoring of the congestion situation.  

Table 20: Activation of FDA UIOLI by TSOs 

Activation of FDA UIOLI 

TSOs 

All IPs 

All Austrian TSOs, All German TSOs, Plinacro (HR) 

Based on TSO’s monitoring 

NET4GAS (CZ), TAP (GR/IT), Snam (IT) 

Based on ACER’s reporting 

IGB (GR/BG), FGSZ (HU), Gaz System (PL), 
Plinovodi (SI) 

Analysis of impacts 

Currently some NRAs rely on the outcomes of ACER’s Congestion Reports to decide on whether FDA 
UIOLI should be activated, while others activate the mechanism based on their assessments and 
consultations with the TSO (including the application of the mechanism at both congested and not 
congested IPs). Both options are included in the intervention, so that the regulation can reflect 
the actual practices applied to trigger FDA UIOLI.  

The immediacy that the NRAs have to activate the FDA UIOLI, as soon as they identify the 
occurrence of  congestion, enhances the adaptability of the CMP rules to the future operation of the 
gas system. This will also require TSOs to quickly adapt their transmission services and apply 
renomination restrictions at the IPs identified as congested.  

Although ACER’s report can be used to activate the mechanism, it is expected that NRAs will also 
undertake  to  examine  congestion  at  the  IPs  of  their  gas  system.  Not  all  NRAs  are  currently 
monitoring closely the daily use of capacity in the network. In these cases, the regular analysis 

86 

            
       
 
 
of the congestion situation at the IPs would require additional effort, slightly increasing the 
regulators’ administrative burden.  

The possibility given to NRAs to activate the FDA UIOLI mechanism if congestion is identified at an 
IP  can  allow  the  swift  release  of  unused  capacity,  before  ACER’s  next  biannual  report  is 
published. This will contribute to the efficient use of the TSO’s system and facilitate network access 
by the users. Nevertheless, NRAs could still rely on the outcomes of the Congestion Reports, thus 
decreasing the potential impact of the intervention.  

The  TSOs  will  continue  using  the  existing  processes,  procedures  and  electronic  platform 
functionalities to apply the renomination restrictions imposed through the FDA UIOLI mechanism. 
It is not expected that the implementation of the regulatory intervention will result in a measurable 
increase of the TSOs’ effort and costs. 

 The regulatory intervention does not result in any additional obligations to the NRAs for publishing 
information about the congestion situation at the IPs. The NRAs can continue their current reporting 
practices,  thus  not  impacting  the  accessibility  to  information  by  network  users  and  other 
stakeholders. 

It is not expected that changes in the trigger of the FDA UIOLI mechanism will have a measurable 
impact on the TSO’s revenues and correspondingly to the costs of network users.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 21: Summary of impacts of activating FDA UIOLI based on ACER’s or NRAs’ monitoring 

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6.4.2  Activation of FDA UIOLI based only on NRAs monitoring  

Size of the intervention 

The regulatory intervention will change the function of ACER’s Congestion Reports from a trigger 
for  FDA  UIOLI  to  an  informative  document  on  the  congestion  situation  at  the  European  IPs. 
Activation of the FDA UIOLI mechanism will be based on the TSOs’ own analysis of capacity use 
and congestion. As shown in Table 20 above, this is already the case for many TSOs that monitor 
the  congestion  situation  themselves  or  apply  renomination  restrictions  at  all  their  IPs.  The 
intervention  will  therefore  primarily  impact  the  few  TSOs  that  are  currently  relying  on    ACER’s 
analysis to activate the mechanism. 

Analysis of impacts 

Linking the decision of the NRAs to activate the FDA UIOLI mechanism with their own monitoring 
of  congestion,  instead  of  relying  on  ACER’s  Congestion  Reports,  will  ensure  that  the  actual 
situation  in  the  gas  system  can  be  swiftly  reflected  in  the  regulation,  strengthening  its 
effectiveness.  

The immediacy that the NRAs have to activate the FDA UIOLI, as soon as they identify the 
occurrence of  congestion, enhances the adaptability of the CMP rules to the future operation of the 
gas system. This will also require TSOs to quickly adapt their transmission services and apply 
renomination restrictions at the IPs identified as congested.  

Implementation of the intervention will require the NRAs to examine congestion at the IPs of their 
gas system. Not all NRAs are currently monitoring closely the daily use of capacity in the network. 
In these cases, the regular analysis of the congestion situation at the IPs would require 
additional effort, slightly increasing the regulators’ administrative burden.  

Close  monitoring  of  the  congestion  situation  by  the  NRAs,  and  activation  of  an  FDA  UIOLI 
mechanism without the time lag of waiting for ACER’s reports, will ensure the swift release of 
unused capacity when a contractual congestion occurs at an IP. Monitoring of the network 
users’  demand  for  capacity  at  a  congested  IP  can  also  facilitate  the  NRAs’  decision  making  on 
whether and when the FDA UIOLI could be triggered to maximize its impact. Thus, the intervention 
can  result  in  the  release  of  unused  capacity  and  its  reallocation  to  other  users,  benefitting  the 
efficient  use  of  the  TSO’s  system  and  facilitating  network  access  by  the  users.  This  impact  will 
particularly  concern  the  Member  States  where  the  NRAs  were  not  activating  the  FDA  UIOLI 
mechanism based on their own assessments.  

The  TSOs  will  continue  using  the  existing  processes,  procedures  and  electronic  platform 
functionalities to apply the renomination restrictions imposed through the FDA UIOLI mechanism. 
It is not expected that the implementation of the regulatory intervention will result in a measurable 
increase of the TSOs’ effort and costs. 

The regulatory intervention does not result in any additional obligations to the NRAs for publishing 
information about the congestion situation at the IPs. The NRAs can continue their current reporting 
practices,  thus  not  impacting  the  accessibility  to  information  by  network  users  and  other 
stakeholders. 

It is not expected that changes in the trigger of the FDA UIOLI mechanism will have a measurable 
impact on the TSO’s revenues and correspondingly to the costs of network users.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

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Table 22: Summary of impacts of activating FDA UIOLI based only on NRAs’ monitoring 

6.4.3  Flexibility in the application of CMPs and market measures 

Size of the intervention 

The  CMP  Guidelines  require  all  Member  States  to  have  in  place  regulatory  provisions  for  the 
application  of  an  FDA  UIOLI  or  an  OS+BB  mechanism.  Once  activated  at  an  IP,  the  FDA  UIOLI 
mechanism will impose the foreseen restrictions to renominations. On the other hand, even if the 
TSO has developed all necessary methodologies and procedures for the OS+BB, it may not offer 
any additional capacity at its IPs.  

The regulatory intervention will impact the TSOs that are currently not using any CMP to release 
capacity  but  rely  solely  on  the  application  of  market-based  measures  as  more  appropriate  and 
sufficient to resolve congestion situations in their transmission systems. The table below presents 
the mechanisms that the Member States have opted for managing congestion, including the cases 
where OS+BB is typically in place but not used in practice. 

Table 23: Application of congestion management measures by Member States 

Measure applied 

Member States 

Renomination restrictions through FDA UIOLI 

AT, BG96, CZ, DE, HR, HU, GR97, IT, PL, SI  

Additional capacity through oversubscription 

FR, GR, NL, PT, SK98, ES 

Reliance on market-based measures 

BE, BG, DK, EE, IE, LT, LV, RO 

96 CMPs in Bulgaria include OS+BB at Bulgartransgaz’ IPs and FDA UIOLI at the interconnector IGB. 

97 CMPs in Greece include OS+BB in DESFA’s IPs and FDA UIOLI at the interconnectors TAP and IGB. 

98 Eustream offered additional capacity only in 2021. 

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It is likely that market-based measures will be prioritized primarily by the NRAs of Member States 
that have not activated the FDA UIOLI mechanism and are not offering additional capacity through 
oversubscription  (currently  8  Member  States).  NRAs  that  are  combining  OS+BB  with  other 
mechanisms  to  manage  occurrences  of  congestion  (currently  6  Member  States),  may  also  shift 
towards a more extensive use of market-based measures (e.g., UBI, interruptible capacity). 

Analysis of impacts 

This regulatory intervention allows NRAs to determine the measures applied to manage contractual 
congestion, in accordance with the characteristics of their market and the current use of their gas 
system. They may choose to apply a combination of market-based measures and CMPs or opt not 
to  apply  an  OS+BB  or  FDA  UIOLI  mechanism.  The  resulting  regulatory  framework  for 
managing congestion can be effectively designed to fit the context and specificities of the 
particular market. It will also help avoiding the inclusion, in the national regulation, of CMP rules 
that  are  not  used  in  practice,  in  situations  where  NRAs  currently  rely  only  on  measures  such  as 
over-nominations and secondary capacity trading to optimize the access to booked but unused firm 
capacity. It should be noted that the flexibility in the application of measures to manage congestion 
may widen the differences in the mechanisms applied at the different sides of an IP. This issue can 
be  mitigated  by  strengthening  the  coordination  between  NRAs  and  TSOs  and  monitoring  the 
harmonized use of capacity at the IP, as discussed in Section 6.6. 

Each  NRA  has  the  flexibility  to  apply  market  measures  and  CMPs  based  on  the  existing 
conditions,  without  being  obliged  to  apply  mechanisms  that  would  not  add  value  to  the 
management of congestion. This enhances the adaptability of the regulatory framework to future 
changes in the gas market and system. This adaptability also benefits the services offered by 
the TSO relating to the management of congestion, which are adjusted following any changes 
in the regulatory framework. 

The selection and design of the appropriate measures would require consultations between the 
NRA and the TSO, as well as with other stakeholders. This could increase the administrative 
burden of the parties involved in this process.  

The  TSOs  would  not  be  required  to  develop  CMP  procedures,  processes,  methodologies 
and  IT  functionalities  if  these  mechanisms  are  not  necessary  in  practice  to  manage 
congestion.  For  example,  a  TSO  would  not  have  to  develop  a  methodology  for  estimating  the 
additional capacity to be offered and carrying out risk assessments for the OS+BB scheme, unless 
the NRA considers that offering of additional capacity is necessary to address the occurrences of 
contractual congestion. This can improve the operational efficiency of the TSO. 

The NRAs, in consultation with the TSOs and other stakeholders, are able to combine preventive 
market-based measures with more intrusive CMPs to maximize the use of available capacity at the 
network points. This will help to avoid the unnecessary release of capacity through CMPs and 
optimize the relation between the amount of capacity released at an IP and the amount reallocated 
to other network users. At the same time, it provides a better fit between the needs of network 
users  without  firm  capacity  rights  and  the  release  of  capacity  through  the  application  of 
OS+BB or FDA UIOLI mechanisms. 

The  intervention  should  include  the  introduction  of  publication  obligations  for  the  TSOs 
and/or NRAs, which showcase the effectiveness and efficiency of the measures selected. 
Such information will facilitate decision making by the network users when planning for the use of 
capacity. It will also improve public access to information. 

It is not expected that changes in the prioritization of congestion measures will have a measurable 
impact on the TSO’s revenues and correspondingly on the costs of network users.  

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Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 24: Summary of impacts of flexibility in the application of CMPs and market measures  

6.5  Area of improvement: Effectiveness and efficiency of the CMPs 

One  regulatory  intervention  is  examined  under  this  area  of  improvement.  Τhis  concerns  the 
consultation between NRAs and TSOs on whether a network user can sell its surrendered capacity 
at the secondary market.  

The impact of this intervention is discussed below. 

6.5.1  Consultation between NRA and TSO for secondary trading of surrendered capacity 

Size of the intervention 

The NRAs of all Member States at which CMPs apply will have to consult with the respective TSOs 
to decide whether secondary trading of surrendered capacity would be allowed in their market. The 
table  below  aggregates  the  amount  of  daily  capacity  that  was  returned  by  network  users  to  the 
TSOs in the past 3 gas years and could potentially have been offered in the secondary market. 

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Table 25: Aggregate amount of surrendered capacity released per gas year 

Member State 

Austria 

Czech Republic 

Germany 

Latvia 

Lithuania 

Netherlands 

Poland 

Gas Year 2021/22 

Gas Year 2022/23 

Gas Year 2023/24 

No of 
IPs 

Released99 
capacity GWh/d 

No of 
IPs 

Released capacity 
GWh/d 

No of 
IPs 

Released capacity 
GWh/d 

3 

2 

4 

- 

- 

11 

1 

33,585 

422,265 

23,072 

- 

- 

91,654 

14 

8 

2 

3 

- 

- 

13 

1 

31,415 

657,365 

41,561 

- 

- 

294,056 

14 

6 

2 

1 

1 

1 

12 

- 

41,784 

603,148 

967 

2,360 

891 

245,701 

- 

The  responses  to  the  survey  have  indicated  that  NRAs  and/or  TSOs  from  only  4  Member  States 
(most of which without any IPs where capacity was returned in the past 3 gas years) agree that 
users surrendering capacity should be allowed to make it available at the secondary market. It can, 
therefore,  be  expected  that  this  regulatory  intervention  will  result  in  secondary  trading  of 
surrendered capacity only at a very small number of IPs, limiting its actual impact. 

Analysis of impacts 

This regulatory intervention does not affect the regulatory effectiveness and adaptability. The NRAs 
already have the option to permit trading of surrendered capacity in the TSO’s network access rules. 

Effort is required by the NRAs to decide, in consultation with the TSOs, whether surrendered 
capacity  can  be  traded  by  the  users.  The  NRAs  may  also  have  to  monitor  secondary  trades,  to 
ensure that capacity rights of a user have only been allocated once. Consequently, the intervention 
results in an additional administrative burden for the NRAs. 

Offering of capacity that a network user is not planning to use at both the primary and secondary 
market  increases  the  channels  through  which  this  capacity  can  be  reallocated. 
Nevertheless, in most cases, if there is interest by other market participants for firm, the network 
users would not have to surrender and trade capacity at the same time. Therefore, the benefits to 
the efficient use of the TSO’s system and network access by the users are limited. 

If an NRA and TSO decide to opt for allowing trading of surrendered capacity, the TSO would have 
to ensure that its processes and procedures minimize the risk of double-selling the same 
capacity in the primary and secondary market. This results in an additional administrative burden 
and costs for the TSO. 

The regulatory intervention does not result in any additional obligations to the NRAs or TSOs for 
publishing  information  that  could  be  taken  into  consideration  by  network  users  or  other 
stakeholders. 

The TSOs’ revenues will not be impacted by the intervention, as the transmission charges will only 
be paid by the user holding the capacity rights.  

The network users may sell their capacity themselves in the secondary market or through the TSO 
in  the  primary  market.  This  increases  the  possibilities  that  a  user  has  to  dispose  of  any  unused 
capacity  and  decreases  its  network  charges,  making  the  use  of  the  system  more  cost-
effective.  

99 The reported capacity released may have been surrendered by network users in the same gas year or in a previous one. 

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Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

Table 26: Summary of impacts of consultation of NRA and TSO for secondary trading of 
surrendered capacity   

6.6  Area of improvement: Harmonization of rules between adjacent TSOs 

One  regulatory  intervention  is  examined  under  this  area  of  improvement.  Τhis  concerns  the 
coordinated monitoring of the use of capacity at an IP by the adjacent NRAs, and the application of 
additional measures if harmonization is necessary.  

The impact of this intervention is discussed below. 

6.6.1  Monitoring the harmonized use of capacity at IPs 

Size of the intervention 

This intervention requires NRAs to monitor the use of capacity at all cross-border IPs with different 
congestion management measures (OS+BB, FDA-UIOLI or market-based measures) applied at each 
side of the network point. As shown in the table below, different measures are in place at many 
cross-border IPs.   

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Table 27: Application of measures to manage congestion at cross-border IPs 

Same measure at both sides of the IP 

Different measure at each sides of the IP 

Of which 

OS+BB – FDA UIOLI 

OS+BB – Market measures 

FDA-UIOLI – Market measures 

No of cross-border IPs 

14 

14 

6 

3 

5 

Application of the intervention will result in several NRAs having to coordinate with their adjacent 
NRA  to  ensure  that  the  application  of  different  measures  does  not  impact  the  operation  of  the 
respective cross-border IPs. 

Analysis of impacts 

Although many NRAs are already monitoring the use of capacity at their IPs, they are rarely doing 
so in a coordinated manner with the adjacent NRA. The intervention would not have an impact on 
streamlining and better reflecting in the regulation the existing practices and approaches. 

The  coordinated  monitoring  by  the  adjacent  NRAs  contributes  to  making  the  regulatory 
framework for managing congestion more adaptable to future changes in the gas market 
which may impact the harmonized operation of an IP. At the same time, the corresponding services 
offered by the TSOs will be modified, so that the measures seeking to address future congestion 
issues are swiftly implemented.  

The NRAs’ obligation to jointly identify and address the cases where the use of different measures 
at  the  two  sides  of  an  IP  is  restricting  the  use  of  capacity,  can  help  with  the  definition  of 
coordinated actions that strengthen the consistency in the TSOs’ activities in managing 
congestion. Use of bundled capacity can be thus strengthened, making the use of the gas network 
more  efficient.  From  the  network  users’  perspective,  undue  restrictions  to  nominations  of 
booked capacity can be avoided, facilitating access to the network.  

The adjacent NRAs will have to monitor the use of capacity at both sides of each IP in a coordinated 
manner and would have to cooperate in case action is needed to modify and improve the applied 
measures  to  manage  congestion.  The  additional  monitoring  obligations  will  increase  the 
administrative burden for the NRAs. Furthermore, if the TSOs must change the measures they 
are  currently  applying  to  harmonize  the  operation  at  the  two  sides  of  an  IP,  then  they  may  be 
required to adjust their processes and procedures for managing congestion or even their 
IT systems, resulting in additional effort and costs. 

The regulatory intervention does not result in any additional obligations to the NRAs or TSOs for 
publishing  information  that  could  be  taken  into  consideration  by  network  users  or  other 
stakeholders. 

Any potential changes that the NRAs may decide to implement to harmonize the use of capacity at 
an  IP,  will  be  specific  to  the  particular network  point. Depending  on  the  scope  and amplitude  of 
such changes, these may or may not impact TSOs’ revenues and network charges. It is thus not 
possible to perform a generalized assessment of this impact, as it is closely linked to the IP-specific 
context. 

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

94 

            
       
 
 
 
Table 28: Summary of impacts of monitoring the harmonized use of capacity at IPs   

6.7  Area of improvement: Transparency 

The regulatory interventions examined under this area of improvement are complementary and are 
setting additional publication requirements for the TSOs: 

• 

• 

Establishment of more detailed provisions for the CMP data to be published by TSOs 

Introduction of new publication requirements for CMP data 

The impact of these interventions is discussed below. 

6.7.1  Additional publication requirements for TSOs 

Size of the intervention 

This  regulatory  intervention  applies  to  all  IPs  for  which  the  respective  TSOs  are  publishing 
information. Depending on the current data reporting practices of the TSO, it may have to publish 
additional  data  on  the  use  of  CMPs  and  ensure  quality  and  consistency  of  the  CMP  data  already 
published.  

As discussed in Section 4.5, only very few TSOs are currently publishing data concerning the amount 
of  daily  capacity  released  through  CMPs  at  a  network  point  that  was  then  reallocated  to  other 
network  users.  The  information  presented  in  Table  29  indicates  the  extent  to  which  data  on 
reallocated capacity are currently published. With the implementation of this intervention, all TSOs 
will have to publish such data for their IPs and therefore would have to adapt their datasets and 
platforms  to  include  information  on  the  daily  reallocation  of  released  capacity.  Furthermore,  the 
(currently 6) TSOs that are offering oversubscribed capacity will have to report data on the amount 
of additional capacity that was booked by network users and the amount bought back by the TSO 
if the buy-back mechanism was triggered.  

95 

            
       
 
 
 
Table 29: Publication of reallocated capacity per type of CMP at IPs with released capacity100 

Type of CMP 

No of IPs with published data 
on reallocation of released 
capacity 

No of IPs without published data 
on reallocation of released 
capacity 

FDA UIOLI 

Surrender 

LT UIOLI 

2 

3 

2 

92 

34 

4 

Additionally, some TSOs will have to adjust their currently reported datasets, to meet the detailed 
transparency  requirements.  For  example,  TSOs  that  have  used  the  CMP  mechanisms  to  release 
capacity for reasons other than managing congestion would have to exclude this information from 
the CMP datasets and report it separately.  

Analysis of impacts 

The intervention focuses on improvements to the publication of information by the TSOs. This can 
improve  the  regulatory  effectiveness  of  the  NRAs,  by  facilitating  their  access  to  the  relevant 
information,  strengthening  their  monitoring  and  supervision  of  the  CMPs’  application  at 
their system.  

The outcomes of the survey have indicated that the publication of information relating to the CMPs 
can benefit the network users’ decision making. Analysing the trends of the amount of capacity 
being released by CMPs and reallocated can help the users’ planning for booking different 
capacity  products,  being  better  informed  on  the  amount  of  daily  capacity  that  may  become 
available  and  assessing  the  risks  of  interruption  of  interruptible  capacity.  At  the  same  time,  the 
intervention  will  facilitate  the  public  access  to  consistent  and  clear  information  about the 
use of CMPs.  

The TSOs will be required to publish additional information concerning the use of CMPs. However, 
the TSOs are already collecting such information, and therefore implementation of this intervention 
is not expected to increase the TSO’s efforts for data collection. Furthermore, the TSOs’ revenues 
will not be impacted by the intervention, as the transmission charges will only be paid by the user 
holding the capacity rights.  

The better informed decisions by network users, through the publication of additional capacity for 
CMPs, could potentially facilitate matching their needs with the available firm capacity, improving 
the efficient use of the network and their access to it, as well as making their use of capacity more  
cost efficient. However, this impact cannot be assessed, as decision making of the network users is 
multifactorial and different for each particular user.  

Summary of impacts 

The  table  below  provides  an  overview  of  the  intervention’s  positive  and  negative  impacts  and  a 
qualitative rating of each impact. 

100 The table includes only IPs with released capacity per type of CMP during the gas years 2021/22, 2022/23, 2023/24. 

Information on OS+BB is not presented, as it concerns the amount of additional capacity offered and booked. 

96 

            
       
 
 
 
Table 30: Summary of impacts of setting additional publication requirements for the TSOs   

97 

            
       
 
 
 
 
 
 
7.  Conclusions and recommendations 

7.1  Overview of examined regulatory interventions 

Figure 36 provides an overview of the regulatory interventions which have been identified in Section 
5 as the options suitable for addressing the shortcomings and challenges, and for meeting the policy 
objectives of each area of improvement. 

Figure 36: Examined regulatory interventions 

Most  of  the  regulatory  interventions  are  complementary  and  can  be  applied  together.  There  are 
however some overlapping interventions , aiming to address the same policy objective:  

•  Both  interventions  2.1  and  2.2  aim  to  set  congestion  management  measures  at  LNG 
terminals,  with  the  former  being  a  less  intrusive  and  the  latter  a  more  interventionist 
approach.  

•  Both interventions 3.1 and 3.2  aim to reduce the reliance of the FDA UIOLI activation on 

ACER’s biannual Congestion Reports. 

One option out of each pair of overlapping interventions is selected for further analysis, based on 
the outcomes of the impact assessment. 

7.2 

Impact of regulatory interventions 

The assessment discussed in Section 6 indicated the positive and negative impacts of the examined 
regulatory  interventions  to  key  areas  of  interest  of  each  affected  actor  (NRAs,  TSOs,  network 
users101) relating to the design and application of CMPs. The outcomes of this assessment are used 
to derive an overall impact for each intervention. The figure below summarizes the impacts of the 
regulatory interventions on the actors and indicates their overall impact.

101 The positive and negative impacts to network users can be passed on (fully or partially) to the final customers. For this 

reason, impacts to final customers are not examined separately. 

98 

            
       
 
 
 
 
Figure 37: Impacts of the regulatory interventions 

Regulatory intervention 

Impact on actors 

Overall impact 102 

1.1  Change of the definition of 

contractually congested network 
points 

1.2  Change in the criterion of “non-

offer” of capacity 

2.1  High-level congestion management 

obligations to LNG terminal 
operators 

•  Strongly enhances regulatory effectiveness 
and facilitates adaptability of regulation. On 
the other hand, it may slightly increase the 
administrative burden for NRAs 

•  Improves the efficient use of the gas 

system, and allows the TSO to adapt its 
transmission services 

•  Facilitates network users’ access and their 

efficient decision making 

•  Strongly enhances regulatory effectiveness 

•  Has no considerable impact on the TSOs’ 

areas of interest 

•  Can slightly improve decision making of 

users and public access to information on 
CMPs 

•  Harmonizes national and European 

regulations and facilitates adaptability of 
regulation to future changes of the market. 
It may slightly increase the NRAs’ burden  

•  Significantly improves efficient use of the 

terminals and facilitates the adaptability of 
the operators’ services. It may slightly 
increase costs of the operator 

•  Facilitates access of users to the terminals 

HIGH 

MODERATE 

MODERATE 

102 Overall impact is based on the extent to which the intervention impacts the affected actors: HIGH: Has significant impact on at least 2 actors; MODERATE: Has significant impact on up to 

1 actor, and/or has moderate impact to 2 or more actors; LOW: Has low impact (i.e. negative effects) on at least 1 actor. 

99 

            
       
 
 
 
 
 
 
Detailed congestion management 
obligations to LNG terminal 
operators 

2.2 

3.1  Activation of FDA UIOLI based on 
either ACER’s or NRAs’ monitoring 

3.2  Activation of FDA UIOLI based only 

on NRAs monitoring 

•  Results in administrative burdens for the 
NRAs and limits the possibilities to adapt 
regulation 

•  Significantly improves efficient use of the 
terminals and may increase the operator’s 
revenues. On the other hand, it increases 
the burden for the operators 

•  Facilitates access of users to the terminals 

•  Slightly enhances regulatory effectiveness 

and facilitates adaptability of regulation. On 
the other hand, it may slightly increase the 
administrative burden for NRAs 

•  Slightly improves the efficient use of the 
gas system, and allows the TSO to adapt 
its transmission services 

•  Facilitates users’ access to the network 

•  Enhances regulatory effectiveness and 

facilitates adaptability of regulation. On the 
other hand, it may slightly increase the 
administrative burden for NRAs 

•  Improves the efficient use of the gas 

system, and allows the TSO to adapt its 
transmission services 

•  Improves users’ access to the network 

LOW 

MODERATE 

HIGH 

100 

            
       
 
 
 
 
 
3.3  Flexibility in the application of CMPs 

and market measures 

4.1  Consultation between NRA and TSO 

for secondary trading of surrendered 
capacity 

5.1  Monitoring the harmonized use of 

capacity at IPs 

•  Strongly enhances regulatory effectiveness. 
Has a significant impact on the adaptability 
of regulation. On the other hand, it may 
slightly increase the administrative burden 
for NRAs 

•  Improves the efficient use of the gas 
system and significantly facilitates 
adaptability of the TSOs’ services. 
Improves the TSOs’ operational efficiency 

•  Improves users’ access to the network 

•  Strengthens transparency and publication 

of CMP information 

•  Results in a slight increase of the NRAs’ 

administrative burden 

•  Slightly improves the efficient use of the 

gas system. On the other hand, increases 
the TSOs’ administrative burden 

•  Improves users’ access to the network. It 

may also slightly decrease the users’ 
system costs 

•  Facilitates adaptability of regulation to 

future changes of the market. On the other 
hand, it may slightly increase the 
administrative burden for NRAs  

•  Improves efficient use of the terminals and 
allows the TSO to adapt its transmission 
services. On the other hand, it may require 
additional effort by the TSOs 

•  Improves users’ access to the network 

HIGH 

LOW / 
MODERATE 

MODERATE 

101 

            
       
 
 
 
 
 
6.1  Additional publication requirements 

for TSOs 

•  Improves monitoring and supervision by 

the NRAs 

•  Has no considerable impact on the areas of 

interest of the TSOs 

•  Facilitates the efficient decision making of 
the network users and improves public 
access to information 

MODERATE103 

103 The overall impact of this intervention is assessed taking into consideration its effect only on the NRAs and network users. The TSOs are not considerably impacted by the intervention. 

102 

            
       
 
 
 
 
Concerning the overlapping regulatory interventions that aim to address the same policy objective, 
the analysis above indicates that: 

• 

• 

Intervention 2.1 has a higher impact than intervention 2.2. Therefore, only the intervention 
setting  high-level  congestion  management  obligations  to  LNG  terminal  operators  will  be 
examined. 

Intervention 3.2 has a higher impact than intervention 3.1. Therefore, only the intervention 
requiring NRAs to monitor the congestion situation at IPs to decide whether to activate an 
FDA UIOLI mechanism will be examined. 

7.3  Comparison of regulatory interventions 

7.3.1  Overview of screening framework 

To determine which of the examined regulatory interventions should be considered as priorities for 
the Commission, these are compared on the basis of their importance, applicability and relevance. 
Screening  of  the  interventions  is  carried  out  qualitatively  (ranked  using  a  Likert  scale  for 
comparability), on the basis of the following screening criteria: 

•  Size of the intervention (extensive – moderate – limited, ranked using 3 – 2 – 1): The 
degree  and  magnitude  to  which  the  intervention  affects  elements  of  the  gas  market. 
Depending on the intervention it may concern aspects such as the NRAs that would have to 
change their regulations, the TSOs that would apply the intervention or the IPs that would 
be actually affected. 

• 

Impact of the intervention (high – moderate – low,  ranked using 3 – 2 – 1): The impact 
of the regulatory intervention on the key areas of interest of the affected actors, as analysed 
in Figure 37. 

•  Legal complexity (low – medium – high, ranked using 3 – 2 – 1): The extent to which 
introduction  of  the  intervention  into  the  current  legal  framework  on  an  EU  level  can  be 
complex. 

•  Coherence with EU policy objectives (good – fair – poor, ranked using 3 – 2 – 1):  The 
degree  to  which  the  regulatory  intervention  is  consistent  with  overall  EU  energy  policy 
objectives of market integration and access, decarbonization and security of supply. 

•  Proportionality  (good  –  fair  –  poor,  ranked  using  3  –  2  –  1):  Examines  the  degree  to 
which the efforts required to implement the intervention are proportionate to the benefits 
that can be expected from achieving the corresponding policy objective. 

7.3.2  Comparison of regulatory interventions 

The table below summarizes the analysis and comparison of the different regulatory interventions 
against the screening criteria. 

103 

            
       
 
 
Table 31: Comparison of the regulatory interventions against the screening criteria 

Regulatory intervention104 

Size 

Impact105 

Legal complexity 

Coherence 

Proportionality 

Change of the definition of 
contractually congested 
network points 

Change in the criterion of 
“non-offer” of capacity 

High-level congestion 
management obligations to 
LNG terminal operators 

Activation of FDA UIOLI 
based only on NRAs 
monitoring 

Extensive: The new 
definition will apply to all 
IPs and will decrease 
considerable the number 
of IP sides identified as 
contractually congested 

Moderate: Most IP sides 
currently identified as 
congested due to non-
offer of capacity are likely 
to no longer be considered 
as congested  

Limited: Only the few 
LNG terminals currently 
relying on the users to 
make their unused 
capacity available have to 
introduce new measures 

Limited: Only the few 
TSOs that are currently 
relying on ACER’s 
Congestion Report will be 
impacted 

High 

Medium: Change of the 
definition of contractual 
congestion requires 
amendment of the 
Regulation. Instead, the 
criteria for congested IPs in 
the CMP GL could be revised 

Good: In line with 
market integration 
and access policy 
objectives  

Moderate 

Low: The criteria for 
contractually congested IPs 
in the CMP GL must be 
amended  

Good: In line with 
market integration 
and access policy 
objectives 

Moderate 

Medium: Introduction of 
new obligations for setting  
congestion management 
measures at the terminals 
requires amendment of 
Article 11 of the recast 
Regulation 

Good: In line with 
market integration 
and access policy 
and security of 
supply objectives 

High 

Low: The monitoring 
obligation of the NRAs 
should be introduced in the 
CMP GL 

Good: In line with 
market integration 
and access policy 
objectives 

Good: Effort is needed to 
use a different definition 
of congestion. On the 
other hand, the change 
will improve the 
identification of congested 
IPs across the EU 

Good: Very limited 
additional effort is 
needed, while the 
identification of congested 
IPs will improve 

Good: Effort would be 
needed only from NRAs 
and operators that 
currently do not apply 
CMPs. This will improve 
access to the relevant 
terminals 

Good: Limited effort is 
needed by NRAs to 
examine the use of 
capacity at their IPs. The 
benefit is significant as 
congestion situations can 
be addressed quickly 

104 The overlapping interventions with lower impact (2.2, 3.1) are excluded from this analysis as discussed in Section 9.2. 

105 Based on the analysis in Section 9.2. 

104 

            
       
 
 
 
Flexibility in the application 
of CMPs and market 
measures 

Consultation between NRA 
and TSO for secondary 
trading of surrendered 
capacity 

Monitoring the harmonized 
use of capacity at IPs 

Additional publication 
requirements for TSOs 

Extensive: The 
prioritization of market 
measures and optional use 
of CMPs will impact at 
least the several TSOs 
currently applying only 
market measures 

Limited: Although all 
NRAs would have to 
consult with the TSOs, it 
can be expected that only 
few TSOs will allow  
trading of surrendered 
capacity 

Extensive: Several NRAs 
will have to monitor their 
cross-border IPs and 
ensure that the 
mechanisms applied are 
not impacting the 
harmonized use of 
capacity 

Extensive: New data 
(e.g., amount of 
reallocated capacity) will 
have to be published for 
most IP sides 

High 

Low: The scope of the CMP 
GL should be amended, to 
allow NRAs to decide on the 
application of market-based 
measures and/or CMPs to 
manage short-term 
congestion 

Good: In line with 
market integration 
and access policy 
objectives 

Low /  
Moderate 

Low: The provisions for 
surrender of capacity in the 
CMP GL should be amended 
to require NRAs and TSOs to 
consult on trading of 
surrendered capacity 

Good: In line with 
market integration 
and access policy 
objectives 

Moderate 

Low: An additional 
obligation for NRAs’ 
monitoring of cross-border 
IPs should be introduced in 
the CMP GL  

Good: In line with 
market integration 
and access policy 
and security of 
supply objectives 

Moderate 

Low: Annex I of the 
Regulation would have to be 
amended to introduce new 
publication obligations 

Good: In line with 
market integration 
and access policy 
objectives 

Good: Effort is needed to 
adjust the congestion 
rules to best fit the 
particular market 
characteristics. 
Nevertheless, this will 
significantly benefit the 
efficient use of the gas 
networks 

Poor: Effort is required by 
all NRAs to consult with 
TSOs. However, it is 
expected that only very 
few TSOs will opt for 
trading of surrendered 
capacity 

Fair: Effort is required by 
all NRAs to coordinate in 
monitoring the impact of 
applying different 
measures. On the other it 
can be expected that 
changes in the existing 
measures to harmonize 
them will be limited 

Good: The TSOs are 
already collecting the 
information to be 
published. Availability 
would benefit the network 
users decision making 

105 

            
       
 
 
 
The  screening  matrix  below  presents  the  assessment  and  comparison  of  the  different  regulatory 
interventions  against  the  criteria.  All  interventions  are  coherent  with  the  EU  energy  policy 
objectives,  and  most  of  them  do  not  showcase  significant  legal  complexities,  as  they  can  be 
introduced by amending the CMP Guidelines. The key differentiating factors among the regulatory 
interventions are their impact and size/magnitude of implementation, as well as their proportionality 
of effort and benefit. 

Figure 38: Screening matrix of regulatory interventions 

Based on their performance on the screening criteria, the interventions can be split into groups with 
a  different  (higher,  medium,  lower)  priority  level  (Figure  39).  This  grouping  indicates  which 
interventions should be considered first by the Commission, as they are more impactful to the gas 
market  and  system  and  at  the  same  time,  they  are  applicable  and  consistent  with  the  wider  EU 
policies. These priorities do not exclude the possibility to combine complementary interventions that 
can be implemented jointly (e.g., established in the same amendment of the provisions of the CMP 
Guidelines) 

106 

            
       
 
 
 
Figure 39: Priorities of regulatory interventions 

7.4  Recommendations on the implementation of regulatory interventions 

The  analysis  carried  out  in  the  study,  of  the  measures  and  practices  for  managing  contractual 
congestion in gas infrastructure across the EU, has given prominence to the regulatory interventions 
needed to overcome challenges and shortcomings relating to the design and application of CMPs, 
with a view to enhancing the efficient use of gas networks. The findings are in line with the feedback 
provided  by  stakeholders  (NRAs,  TSOs,  network  users)  during  the  interviews  and  the  survey  on 
CMPs (Annex V).  

The most impactful regulatory interventions focus on the measures applied to manage congestion 
at the gas transmission systems. Targeted revisions to the CMP Guidelines can better reflect 
the actual practices followed to manage congestion, strengthen the adaptability to future changes 
in the gas market and improve transparency. Based on the comparison of the interventions, it is 
recommended that a future revision of congestion management rules consider giving priority to: 

1.  Revise  the  definition  of  contractually  congested  network  points.  The  criteria  in 
Point 2.2.3(1) of the Guidelines could be amended to better reflect the congestion situation 
at IPs: 

(i)  The definition used to determine which IP sides are contractually congested should 
avoid,  to  the  extent  possible,  overlaps  with  cases  of  only  physically  congested 
network points. Such a definition includes the network points with booked but 
unused  capacity  and  with  unmet  demand  of  network  users  for  firm 
capacity.  This  combines  the  cases  where  booked  capacity  is  underutilized  with 
actual interest from market participants to use this capacity if it becomes available. 

(ii)  Identifying  IP  sides  as  congested  because  no  firm  capacity  was  offered  at  the 
auctions should focus only on situations where all relevant firm capacity has 

107 

            
       
 
 
 
already been sold out. Although this intervention is a medium priority one, it is 
complementary  to  point  (i)  above  and  could  thus  be  introduced  if  a  complete 
revision of the congestion criteria in the Guidelines takes place. 

2.  Prioritize the use of market-based measures and allow activation of OS+BB or 
FDA UIOLI only if needed, in case the market measures are not efficient or sufficient. 
Such a flexibility allows NRAs to decide on the measures to manage short-term contractual 
congestion  based  on  the  particular  characteristics  of  their  gas  market  and  system  and 
avoid  the  establishment  of  unnecessary  rules  and  mechanisms  that  will  not  apply  in 
practice.  Market  measures  (e.g.,  use  of  interruptible  capacity,  over-nominations, 
secondary  trading,  other  mechanism  such  as  UBI)  can  be  combined  with  the  CMPs,  to 
achieve the most efficient use of capacity.  

Another  intervention  to  be  considered  is  to  extend  the  TSOs’  publication  requirements  for 
CMPs. Further detailing the provisions of the Gas Regulation regarding the publication requirements 
of the TSOs will improve data consistency and quality. At the same time, additional information, 
especially  regarding  reallocation  of  capacity  released  through  CMPs,  may  facilitate  the  network 
users’ decision making and the NRAs’ regulatory oversight. The type of additional CMP data to be 
published  should  seek  to  strengthen  the  market  participants’  efficient  decision  making  when 
scheduling their use of capacity and ease the NRAs’ access to information to monitor the operation 
of network points.  

Further to the above, other interventions, that could be considered with less priority, include: 

1.  Activate  the  FDA  UIOLI  mechanism  based  on  NRAs’  monitoring  of  congestion. 
Instead of relying on the results of ACER’s biannual Congestion Report, NRAs should monitor 
the congestion situation at their IP sides to decide whether the renomination restrictions of 
FDA UIOLI should be triggered. 

2.  Set  an  obligation  to  NRAs  to  ensure  harmonized  use  of  capacity  at  their  cross-
border IPs. Adjacent NRAs should monitor the use of capacity at the two sides of an IP if 
different  measures  are  applied  to  manage  contractual  congestion.  In  case  they  identify 
undue  restrictions  to  the  use  of  capacity  or  other  barriers,  they  should  proceed  with 
proactive or mitigating actions to improve harmonization of the applied measures. 

With the increasing use of monthly, daily and within-day capacity products at most European gas 
transmission  systems,  management  of  congestion  becomes  more  directed  towards  short-term 
measures. Nevertheless, LT UIOLI should remain in the CMPs as a safeguard mechanism to 
manage long-term congestion. Although it is very likely that activation of such a mechanism will 
not be needed in the future, it remains a valuable tool for the NRAs and TSOs to act upon cases of 
network underutilization, and at the same time it provides a disincentive to market participants to 
use capacity hoarding as a means for market manipulation. 

Ensuring the utilization of available capacity at LNG terminals and UGSs is also of high importance 
for  the  efficient  use  of  gas  networks.  Due  to  their  operational  differences  from  the  transmission 
systems, managing congestion at these facilities requires different measures to maximize the access 
to  booked  but  unused  capacity.  At  the  LNG  terminals,  a  regulatory  intervention  could  set  high-
level  congestion  management  obligations  to  LNG  terminal  operators.  Such  an  obligation 
can  take  medium  priority,  as  its  impact  focuses  particularly  on  the  terminals  at  which  the 
operators do not have the right to activate mechanisms that unilaterally release booked but unused 
capacity. At the UGSs, the application of congestion management measures depends heavily on the 
national  regulations  in  place.  Thus,  a  uniform  approach  in  managing  congestion  at  UGSs, 
even at a high-level, cannot effectively apply. 

108 

            
       
 
 
Annex I: Country briefs on CMP rules 

Austria 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB 

- 

FDA-UIOLI 

 (all IPs) 

Surrender 

LT-UIOLI 

 

 

Surrender of capacity106 

- 

- 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

The same rules apply for both TSOs, TAG and Gas Connect Austria. 

The TSO accepts the surrender of booked firm capacity by a network user at IPs and interfaces with 
UGSs. The surrender mechanism applies to yearly, quarterly, and monthly capacity products, but 
not to capacity products with a term of one day or less. 

To facilitate the allocation of short-term capacity products, the TSO shall reserve quotas during the 
annual yearly capacity auctions. Specifically, 10% of the technical capacity for the upcoming five 
years and 20% for the subsequent ten years shall be set aside for this purpose. 

The TSO accepts requests to surrender capacity for up to the next 15 gas years. In case, however, 
the surrendered capacity is not in line with the annual quotas for offering short-term capacity107, 
the TSO does not offer this surrendered capacity during the corresponding annual yearly capacity 
auction. 

If the surrendered yearly capacity is not offered in the annual yearly auction, it is returned to the 
network user. The user may then surrender the capacity again for subsequent quarterly, monthly, 
or day-ahead auctions. Each surrender attempt must be accompanied by a new request, i.e., this 
procedure is initiated by the network users and not automatically by the TSO (the TSO does not 
roll-over capacities). 

Requests to surrender capacity must be submitted no earlier than 30 days before the publication of 
the auction and no later than: 

•  Monthly products: Two working days before the publication day, by 11:00 a.m. 

•  Quarterly products: Two working days before the publication day, by 11:00 a.m. 

•  Yearly products: Two working days before the publication day, by 11:00 a.m. 

Network users retain their rights and obligations under the existing capacity contract for any portion 
of capacity that is not successfully reallocated to another user. During the surrender period (from 

106 The mechanism is described in the “General Terms and Conditions for Transmission Network Access of Trans Austria 

Gasleitung GmbH” (link).  

107 10% of the technical capacity for the upcoming five years and 20% for the subsequent ten years must be set aside for 

short-term (quarterly and shorter-term) capacity. 

109 

            
       
 
 
 
the surrender by the user until the conclusion of the related capacity auction), users are not allowed 
to sell the corresponding capacity at the secondary market. 

If multiple network users surrender capacity with the same product quality at the same network 
point, the TSO offers the surrendered capacity on a first-come first-served basis.  

In case the surrendered capacity is partially or fully reallocated, the network user still has to pay 
any auction premia that occurred at the time that the capacity was initially booked. The user must 
also  pay  to  the  TSO  any  deficit  between  the  initial  network  charges  and  the  charges  for  the 
reallocated capacity. Furthermore, the user is not entitled to any auction premia that occurred when 
the surrendered capacity was reallocated. 

Firm day-ahead use-it-or-lose-it108 

The FDA UIOLI mechanism sets restrictions to the renominations at all IPs, irrespective of whether 
they have been identified as congested in ACER’s Congestion Report. Renominations are allowed if 
they do not exceed 90% or fall below 10% of the booked firm capacity. For nominations of at least 
80% of the booked firm capacity, upward renomination is permitted for half of the non-nominated 
range. Conversely, for nominations of no more than 20% of the assigned firm capacity, downward 
renomination is allowed for half of the nominated range. 

Capacity  released  through  this  mechanism  is  offered  as  daily  firm  capacity  by  the  TSO,  at  the 
capacity  auctions.  A  network  user  whose  capacity  has  been  released  must  still  pay  its  network 
charges to the TSO. 

If a renomination of firm capacity exceeds or falls short of the permissible range, only the portion 
within  the  booked  capacity  is  accepted.  Any  excess  or  shortfall  beyond  the  permissible  range  is 
treated as a nomination of interruptible capacity and is the first to be interrupted if needed. 

The renomination restrictions do not apply to daily or within-day firm capacity products. Also, the 
restrictions do not apply to network users who have booked less than 10% of the technical annual 
capacity at an IP side over the past 365 days. 

The FDA UIOLI mechanism should not be detrimental to the bundling of capacity. For this reason, 
the Ordinance allows the TSOs to deviate from the full application of the mechanism at cross-border 
IPs  at  which  the  adjacent  TSO  is  applying  similar  restrictions,  if  this  is  necessary  to  ensure 
compatibility with the neighboring market area. 

Long-term use-it-or-lose-it109 

Network  users  are  required  to  promptly  offer  fully  or  partially  unused  firm  capacities  at  the 
secondary market, or to surrender it to the TSO. 

The TSO, upon providing written notice, may partially or fully withdraw any long-term firm capacity 
of a network user that has been booked but is being systematically unused. The mechanism applies 
only to capacity with duration of over one year and is subject to other network users requesting 
this capacity. The released capacity is marketed by the TSO as primary capacity. 

Capacity is considered to be systematically unused if the following criteria apply: 

•  The  balance  group  responsible  party  uses  less  than  80%  of  the  capacity  allocated  to  its 
balance  group  or  sub-balance  account,  on  average,  over  a  contract  term  exceeding  one 
year, during the periods from 1st April to 30th September and 1st October to 31st March. 

108 The mechanism is described in the “Gas Market Ordinance 2020”(link). 

109 The mechanism is described in the “Gas Market Ordinance 2020” (link). 

110 

            
       
 
 
 
•  The balance group responsible party systematically nominates nearly 100% of the allocated 
capacity  and  subsequently  renominates  downwards  to  avoid  the  restrictions  of  the  FDA 
UIOLI mechanism. 

If  a  network  user  has  allocated  its  booked  capacity  to  multiple  balance  groups  or  sub-balance 
accounts,  the  assessment  of  systematically  unused  capacity  is  conducted  for  the  total  capacity 
allocated across all balance groups or sub-balance accounts. 

After the LT UIOLI mechanism has been activated, the user is called to justify the underutilization 
of  booked  capacity  within  2  weeks  from  the  TSO’s  notification.  The  TSO  does  not  withdraw  the 
capacity, in case: 

• 

• 

• 

The underutilized part of the capacity was offered by the user at the secondary market, at 
a  price  that  does  not  significantly  exceed  the  network  charges  originally  payable  to  the 
TSO, or 

The underutilized part of the capacity was surrendered to the TSO, or 

The capacity is required in full by the user to fulfil obligations deriving from existing gas 
procurement or gas supply contracts. 

If  the  user  does  not  justify  the  underutilization  of  capacity,  the  TSO  proceeds  with  withdrawing 
long-term capacities. The capacity released for the remainder of the contract duration corresponds 
to the average underutilized capacity. In cases where multiple network users contribute capacity to 
a balance group or sub-balance account, the capacity is released on a pro-rata basis according to 
the capacities contributed by each user. 

The TSO must inform the NRA immediately when the LT UIOLI mechanism is to be activated, along 
with details about the planned capacity withdrawal and any supporting evidence provided by the 
user to justify the underutilization. 

The network user retains its rights and obligations under the capacity contract for any portion of 
the capacity not reallocated as primary capacity by the TSO. 

Management of congestion at underground storage facilities110 

Contracts for the provision of storage services must include measures to prevent capacity hoarding. 
In  cases  of  contractual  congestion,  storage  users  are  required  to  resell  any  unused  contracted 
capacity on a secondary market platform to third parties without delay. 

If a storage user systematically has booked but unused capacity and does not resell this capacity 
following notification by the SSO, then the SSO proceeds with withdrawing the unused capacity for 
the  period  up  to  the  following  31  March.  Nevertheless,  storage  capacity  held  by  electricity 
generation facilities, to manage electricity system congestion or to provide balancing services in the 
electricity market, is not considered systematically unused. 

The withdrawn capacity is marketed by the SSO, and any resulting revenue is used to reduce the 
relevant storage user’s storage fee, minus an adequate administrative fee for the SSO. The storage 
user  retains  its  rights  and  obligations  under  the  storage  contract  for  any  capacity  that  is  not 
reallocated by the SSO. 

110 The mechanism is described in the “Gas Act 2011”(link). 

111 

            
       
 
 
 
Use of congestion revenues111 

The  revenues  resulting  from  capacity  auctions  and  the  reallocation  of  capacity  using  the  CMPs 
(surrender of capacity, FDA UIOLI and LT UIOLI) are defined annually, and used to decrease the next 
year’s tariffs. 

111 Information is included in the for the gas TSOs for the current regulatory period (link). 

112 

            
       
 
 
 
 
 
 
 
Belgium 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

 

- 

 

 

- 

- 

- 

 

- 

- 

- 

- 

- 

- 

- 

 

Oversubscription and buy-back 112 

The  TSO  has  the  right  to  offer  to  network  users  additional  firm  capacity,  beyond  the  technical 
capacity, at an IP. The additional capacity is offered as primary capacity. The TSO must inform the 
NRA about the quantity of additional capacity offered. 

If the TSO cannot accommodate the nominations submitted by network users holding firm capacity 
(including additional capacity) due to technical limitations of the transmission system, the TSO can 
apply  a  market-based  buy-back  scheme,  allowing  network  users  to  sell  their  additional  capacity 
back to the TSO. The buy-back procedure includes the following steps: 

1.  The TSO notifies the network users holding firm capacity at the affected IP that the buy-
back procedure is initiated. The notification specifies the quantity, direction, and period of 
the buy-back. A minimum buy-back lead time of the next full hour plus four hours applies. 

2.  Network users are invited to submit capacity buy-back offers using the appropriate form 
available on the TSO’s website. These offers must include the price and quantity the user 
is willing to sell back to the TSO and must be submitted before the defined deadline. 

3.  After the submission deadline, the TSO classifies all received offers in ascending order based 

on bid price, up to a predefined maximum capacity buy-back price. 

4.  The TSO informs network users of its decision regarding the capacity buy-back offers. Offers 

may be fully accepted, partially accepted, or entirely rejected. 

5.  Network  Users  whose  capacity  was  bought  back  through  this  process  are  credited 

accordingly. 

The buy-back price that can be offered by network users is capped to a maximum that is currently 
set as follows: 

• 

• 

For  capacity  auctioned  daily  as  a  bunded  product:  125%  of  the  payable  price  for  daily 
capacity, for the day for which capacity has to be bought back 

For capacity not auctioned daily as a bunded product: 300% of the payable price of daily 
capacity 

If the offers from network users, accepted by the TSO, do not allow buying back sufficient capacity 
to  fully  meet  the  nominations  for  firm  capacity,  then  the  TSO  may  revise  the  hourly  confirmed 
quantities at the IP, by setting constraints to the daily capacity booked the day before. 

112 The mechanism is described in the “Access Code for Transmission” (link). 

113 

            
       
 
 
 
Surrender of capacity113 

Network users have the option to surrender unused firm capacity at IPs for products with a duration 
exceeding one day.  

Capacity can be surrendered either via the PRISMA platform or directly to the TSO and must align 
with  one of the standard capacity products defined in the CAM Network Code (yearly, quarterly, or 
monthly).  When  surrendering  capacity,  the  user  must  specify  key  details  such  as  the  quantity, 
period, IP, and flow direction of the returned capacity. 

The  network  user  cannot  surrender  capacity  that  is  offered  in  the  secondary  market, to  prevent 
double allocation through both the surrender process and the secondary market. If the capacity is 
being offered in the secondary market, then the user must first withdraw it and then surrender it 
to the TSO. 

Capacity  must  be  surrendered  at  least  2  working  days  before  the  publication  of  the  upcoming 
auction, in order for the surrendered capacity to be offered by the TSO in that auction. The TSO 
informs the user if the surrendered capacity was reallocated within 2 working days following the 
closure of the relevant auction. 

The network user retains all rights and obligations under the capacity contract until the surrendered 
capacity has been reallocated. The TSO credits to the network user any auction premium generated 
during the reallocation of the surrendered capacity and charges the user an administrative fee. 

If multiple network users surrender capacity and not all surrendered capacity can be reallocated, a 
first-come  first-served  principle  applies.  If  multiple  requests  are  received  simultaneously,  the 
available capacity will be reallocated on a pro-rata basis relative to the requested quantities.  

Long-term use-it-or-lose-it114 

The  regulators  of  Belgium,  the  Netherlands  and  the  UK  have  agreed  on  a  vision  for  the 
implementation of the LT UIOLI mechanism in line with the CMP Guidelines115. This vision defines  
the key elements of the mechanism, including the monitoring procedure, definition of key terms, 
and the criteria for activation. 

The TSO maintains an electronic register with the utilization of capacity by the network users and 
submits the register to the NRA at least on a yearly basis. The NRA evaluates whether subscribed 
capacity  remains  systematically  underutilized.  Contracted  capacity  is  considered  systematically 
underutilized if a network user utilizes, on average, less than 80% of its contracted capacity during 
both the periods from 1st April to 30th September and from 1st October to 31st March, provided the 
contract  has  an  effective  duration  of  more  than  one  year  and  no  proper  justification  for 
underutilization is given. 

The TSO informs the NRA and the concerned network users in case of systematic underutilization 
at  a  network  point.  The  TSO  asks  each  affected  user  to  justify  the  underutilization  of  booked 
capacity, and how it intends to utilize it, within a timeframe of 10 working days.  

If  the  underutilization  is  not  justified,  and  the  capacity  was  not  sold  or  offered  at  reasonable 
conditions  in  the  secondary  market116,  the  NRA  may  require  the  TSO  to  withdraw  the  user’s 
underutilized capacity partially or fully. The withdrawn capacity is offered by the TSO as primary 
capacity, for a period of at least two months. The network user retains its rights and obligations for 

113 The mechanism is described in the “Access Code for Transmission” (link). 

114 The mechanism is described in the “Access Code for Transmission” (link). 

115 ACM, Ofgem, CREG Vision Paper LT UIOLI (link). 

116 In such cases, in order to avoid abuse, the price of the concerned capacity offered on the secondary market is capped up 

to the regulated tariffs. 

114 

            
       
 
 
 
the withdrawn capacity under the transmission contract until the capacity is reallocated and to the 
extent that the capacity has not been reallocated. 

If  the  withdrawn  capacity  is  reallocated,  the  network  user  remains  responsible  for  paying  the 
network charges for the reallocated capacity. At the same time, the TSO credits the network user 
for the reallocated capacity at the regulated tariff, reduced by an administrative fee. 

Other measures to manage congestion at the transmission system117 

The  TSO  uses  over-nomination  as  the  main  mechanism  to  manage  short-term  contractual 
congestion.  

Interruptible within-day services are implicitly allocated using over-nomination, on the basis of the 
following principles: 

•  Over-nomination is activated if all firm capacity has been sold after the day-ahead or within-

day auction. 

• 

• 

The TSO notifies network users urgent market message on its electronic platform that over-
nomination has been activated. 

If over-nomination has been activated on the particular time by the TSO, then a network 
user  can  implicitly  be  allocated  over-nomination  capacity  by  submitting  a  nomination 
exceeding their booked capacity. 

•  Over-nomination capacity is allocated until the end of the gas day, on a  first-come first-

served basis. 

• 

The  network  user  is  charged  for  allocated  over-nomination  capacity  at  the  interruptible 
tariff.  

Management of congestion at LNG terminals118 

The  LNG  terminal operator  must  promote  a  "Use  or  Sell" principle,  by  facilitating  the transfer  of 
LNG services via the secondary market, to encourage efficient capacity utilization. In this respect, 
the terminal users have the right to either sell any unused capacity to other users, or to return the 
capacity to the terminal operator, so that the latter makes it available at the secondary market. 

The user must notify the terminal operator at least two months in advance of any LNG services it 
does not intend to use. The terminal operator must then post a notice on its website indicating the 
availability  of  the  services  for  sale.  However,  if  the  notice  is  received  less  than  5  working  days 
before the scheduled services, the operator is not obligated to publish the availability.  

The price of the offered capacity is set by the surrendering user, and if an offer below the posted 
price is received, the sale shall proceed only with the explicit consent of the surrendering user. Once 
the  service  is  sold,  the  terminal  operator  promptly  informs  the  surrendering  user.  The  terminal 
operator charges a 3% fee on the proceeds of the sale. 

The surrendering user retains its rights and responsibilities in accordance with the contract for LNG 
services, until the services are sold to another user. 

117 The mechanism is described in the “Access Code for Transmission” (link). 

118 The mechanism is described in the “LNG Access Code” (link). 

115 

            
       
 
 
 
 
 
Management of congestion at underground storage facilities119 

Storage users may sell their unused capacity directly to other users at the secondary market but 
cannot surrender this capacity to the SSO. 

A use-it-or-lose-it mechanism is in place. The SSO must monitor the use of capacity at the storage 
facilities. In case of congestion, the SSO must take action to release any booked but unused capacity 
and reallocate it to other storage users. Congestion occurs if there is no storage capacity available 
at the primary market and a storage user has requested capacity. 

In case of congestion, the SSO must notify the NRA about the unused capacity, the impacted users 
and the measures taken to resolve or minimize the congestion. The SSO also requests from the 
storage  users  not  intending  to  use  their  capacity  to  trade  their  capacity  rights  in  the  secondary 
market and prove that they are either using or selling their capacity within 10 working days.  

Depending on whether the storage users have proven that they used or sold their capacity, the NRA 
may decide to release the unused capacity partly or fully, and/or to cap the price of the capacity 
sold at the secondary market to the storage tariff. Any released capacity is sold by the SSO at the 
secondary market, priced at the storage tariff. 

The  SSO  reimburses  the  tariff  paid  by  storage  users  for  the  released  capacity,  decreased  by  an 
administrative fee. 

Use of congestion revenues 

Revenues resulting from auction premia and the use of CMPs can be used either to lower tariffs, by 
reducing the allowed revenue to be recovered, or to support the financing of future investments at 
the affected IPs. 

119 The mechanism is described in the “Access for Storage” (link). 

116 

            
       
 
 
 
 
 
 
 
 
 
Bulgaria 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 120 

The TSO may offer additional firm capacity through oversubscription, at IPs with neighbouring EU 
Member States. The additional daily capacity is made available only when the technical capacity at 
the  respective  IP  has  been  fully  booked.  This  additional  capacity  is  offered  as  part  of  the  firm 
capacity day-ahead product. In some cases, additional capacity may also be offered on a monthly 
basis, based on an analysis conducted by the TSO. 

Additional capacity on a day-ahead basis must be announced by the TSO on its electronic platform 
no later than 10:00 on the day preceding the gas day the product relates to. Additional monthly 
capacity must be announced on the day before the auction for a monthly product. 

The TSO determines the volume of additional capacity based on statistical data regarding the actual 
physical usage of the IP. This assessment incorporates a risk analysis related to oversubscribing 
capacity. 

If  additional  capacity  beyond  the  technical  limit  is  provided,  and  it  becomes  evident  that  the 
transmission of all requested quantities cannot be fulfilled at the IP, leading to potential physical 
bottleneck, a capacity buy-back mechanism is implemented. 

To  activate  the  buy-back  mechanism,  the  TSO  notifies  the  network  users  who  have  booked 
additional  (daily  or  monthly)  capacity  at  the  IP  through  the  oversubscription  mechanism.  This 
notification, which includes details about the total capacity subject to buyback, is published on the 
day prior to the use of the capacity.  

Users interested in selling their capacity back to the TSO must prepare a bid for buy-back capacity 
in a form published on the TSO’s electronic platform. The bid must be submitted by 19:00 on the 
day before the use of the capacity. The bid price cannot exceed the daily product price announced 
by the TSO for the respective IP. The TSO assesses the proposals on the basis of the lowest price 
offered.  The  TSO  purchases  only  the  capacity  necessary  to  address  the  physical  congestion, 
specifically  the  additional  reserved  capacity  that  cannot  be  fulfilled  under  the  oversubscription 
mechanism. 

If the offers from the network users are not sufficient to address the congestion, the TSO reduces 
the firm capacity of all users booked under the oversubscription mechanism proportionally (ratio of 
capacity booked by the user under the oversubscription mechanism to the total booked capacity at 
the IP under the oversubscription mechanism) and notifies the affected users no later than 8:30 on 
the day before the use of the capacity. In cases where capacity is reduced, the TSO reimburses the 

120 The mechanism is described in the “Congestion Management Procedures in case of contracted congestion” (link). 

117 

            
       
 
 
 
affected  users  for  the  network  charges  under  the  transmission  contract  corresponding  to  the 
reduced capacity. 

Surrender of capacity121 

Network users who hold firm capacity have the right to return unused capacity back to the TSO. 
This  capacity  can  then  be  reallocated  to  other  users,  provided  all  available  firm  capacity  at  the 
relevant  IP  has  already  been  fully  booked.  Monthly,  quarterly  and  annual  capacity  can  be 
surrendered,  and  the  mechanism  is  not  applicable  to  additional  capacity  reserved  under  the 
oversubscription mechanism. 

Network users must submit an offer to surrender their capacity, specifying the IP side, product and 
offered price. The price must not exceed the tariff for the corresponding capacity product. 

The TSO evaluates offers  for surrendered capacity based on the offered price, prioritizing lower-
priced  proposals.  Capacity  is  purchased  from  users  only  if  the  returned  capacity  is  successfully 
reallocated to another network user. 

Surrender of capacity does not relieve the user of their rights and obligations under the existing 
fixed capacity contract. These rights and obligations remain in effect until the returned capacity is 
successfully reallocated to another user. 

Upon successful reallocation of the returned capacity, the user offering the capacity is reimbursed 
its value, calculated based on the offered price. The user receiving the reallocated capacity pays 
the network charges for the corresponding capacity product. 

Long-term use-it-or-lose-it122 

The TSO analyses the use of contracted long-term capacity (yearly product or consecutive quarterly 
products covering at least two years) every six months, in order to flag out cases of booked but 
systematically underutilized capacity. The monitoring period evaluates the previous 12 months.  

Contracted capacity is considered systemically underutilized if it has an effective duration of more 
than one year and the network user utilizes, on average, less than 80% of their contracted capacity 
over two distinct monitoring periods (collectively forming the annual monitoring period), from 1st 
April  to  30th  September  and  from  1st  October  to  31st  March.  The  capacity  is  not  considered  as 
systemically underutilized if the user can provide a valid justification for the limited use. 

If  other  network  users  have  submitted  requests  for  firm  capacity  during  the  monitoring  period, 
which have been rejected due to a lack of available capacity, and there is evidence of systemically 
underutilized capacity by at least one user during the same period, the TSO must notify the NRA. 
The  TSO  must  provide  a  detailed  and  reasoned  opinion  to  the  NRA,  either  proposing  actions  to 
withdraw unused capacity or recommending no action, supported by a cost-benefit analysis of the 
potential impact of capacity withdrawal on the TSO’s revenues. 

Based on the information and opinion provided by the TSO, the NRA assesses whether the network 
user’s  capacity  at  the  IP  should  be  withdrawn.  In  this  case,  the  NRA  notifies  the  user  in  writing 
about  the  initiation  of  the  capacity  withdrawal  procedure,  specifying  the  amount  of  capacity 
withdrawn, and the time period for which the capacity will be offered to other users. The maximum 
withdrawal period is one year. 

The impacted network user has 14 days for submitting an opinion and justification regarding the 
reasons for not using the capacity. If the network user fails to provide a valid justification within 

121 The mechanism is described in the “Congestion Management Procedures in case of contracted congestion” (link). 

122 The mechanism is described in the “Congestion Management Procedures in case of contracted congestion” (link). 

118 

            
       
 
 
 
the specified period, or if the submitted justification is deemed insufficient, the NRA may adopt a 
decision to withdraw the unused capacity. The maximum capacity that can be partially withdrawn 
is 50% of the unused contracted capacity for the particular IP. 

If  the  NRA  determines  that  the  user  has  provided  a  valid  justification  for  underutilization,  it 
terminates the withdrawal procedure and notifies both the user and the TSO. 

Management of congestion at underground storage facilities 

The  SSO  manages  storage  capacity  without  resorting  to  any  congestion  management  measures. 
Unused injection/withdrawal capacity is offered at day-ahead and within day auctions on the RBP 
platform, in order to maximize the offered level and utilization of the technical capacity of the UGS. 

119 

            
       
 
 
 
 
 
Croatia 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB123 

 

FDA-UIOLI 

 (all IPs) 

Surrender 

LT-UIOLI 

 

 

- 

- 

- 

- 

Oversubscription and buy-back 124 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

In the event of contractual congestion, the TSO must develop and submit to the NRA a mechanism 
for offering additional firm capacity through oversubscription and implementing a buy-back scheme 
at IPs with neighboring Member States. This mechanism should be based on an incentive regime 
published by the NRA. The additional capacity should be offered as bundled capacity to the extent 
possible, subject to agreement with the neighboring TSO. 

The  TSO  may  propose  the  application  of  the  oversubscription  mechanism  at  an  IP,  if,  based  on 
statistical data, the following criteria apply: 

•  Contractual congestion has occurred during the same period in each of the past five gas 

years. 

• 

Interruptible  capacity  at  a  specific  interconnection  point  was  contracted  during  three 
consecutive gas years but was not interrupted. 

•  At least 10% of the technical capacity at a specific interconnection point remained unused 

in each of the past five gas years. 

In case, following the allocation of additional capacity at an IP, the TSO determines that the total 
nominations from all network users for a specific gas day exceed the technical capacity of the IP, it 
shall  initiate  the  buy-back  mechanism  for  the  contracted  firm  capacity.  The  rules  governing  this 
buy-back process must adhere to principles of non-discrimination, transparency, and market-based 
operation. 

In practice, the oversubscription mechanism has not been activated for any IPs. Instead, an FDA 
UIOLI mechanism is applied. 

Firm Day Ahead use-it-or-lose-it125 

A  firm  day-ahead  use-it-or-lose-it  mechanism  applies  at  all  IPs  with  other  EU  Member  States, 
regardless of whether these were identified as congested in ACER’s Congestion Report.  

The mechanism restricts the nominations and renominations of the network users for firm capacity 
at the IPs in accordance with the following rules: 

•  Nominations: 

123 Although the OS+BB mechanism is foreseen in the regulation, the FDA UIOLI has been applied in practice at the IPs. 

124 The mechanism is described in the “Transmission System Network Code” (link). 

125 The mechanism is described in the “Transmission System Network Code”  (link). 

120 

            
       
 
 
 
o  For users nominating up to 80% of their contracted capacity, 10% of the capacity 

will be withdrawn. 

o  For users nominating more than 80% of their contracted capacity, half of the non-

nominated capacity will be withdrawn. 

•  Renominations: 

o  For  users  nominating  between  20%  and  80%  of  their  contracted  capacity, 
renomination is allowed up to a maximum of 90% and a minimum of 10% of the 
contracted capacity. 

o  For users nominating more than 80% of their contracted capacity, renomination is 
allowed up to a maximum of half of the non-nominated capacity and a minimum of 
10% of the contracted capacity. 

o 

for  users  nominating  up  to  20%  of  their  contracted  capacity,  renomination  is 
allowed up to a maximum of 90% and a minimum of half of their nomination. 

The rules above apply to network users who have booked capacity at an IP equal to or exceeding 
10% of the average technical capacity for the IP in the previous gas year. 

The capacity withdrawn from network users at an IP is offered at daily auctions for primary capacity 
rights. At the end of the respective auction: 

• 

• 

If  the  contracted  capacity  is  less  than  the  available  capacity,  the  withdrawn  capacity  is  
returned to the network users. 

If the contracted capacity exceeds the available capacity, but remains below the technical 
capacity,  any  remaining  uncontracted  withdrawn  capacity  is  returned  to  each  user 
proportionately to their share of the total withdrawn capacity. 

Any portion of the withdrawn contracted capacity that was not returned to users can be used by 
them  as  interruptible  capacity.  Nevertheless,  the  network  charges  paid  by  the  users  for  the 
withdrawn  capacity  will  remain  those  stipulated  in  the  transmission  contract,  and  will  not  be 
reduced, regardless of the number of interruptions. 

Surrender of capacity126 

In  the  event  of  contractual  congestion  at  an  IP  with  an  EU  Member  State,  a  network  user  may 
surrender  its  contracted  firm  capacity  to  the  TSO  if  it  is  not  planning  to  use  it.  A  user  cannot 
surrender capacity contracted as daily and within-day standard capacity products. 

To initiate this process, the network user must submit a request to the TSO no later than three days 
prior to the intended surrender date. The user must also transfer its relevant capacity rights to the 
TSO in the secondary market. 

If a user surrenders at the same time yearly, quarterly, and/or monthly standard capacity products, 
and demand for capacity is less than the total amount of capacity surrendered, the TSO will allocate 
capacity in the following order: monthly capacity first, followed by quarterly capacity, and finally 
yearly capacity. 

Until  the  TSO  reallocates  the  surrendered  capacity  to  another network  user  and  provides  formal 
notice of the allocation, the user surrendering capacity retains all its rights and obligations under 
the transmission contract for the surrendered capacity. 

126 The mechanism is described in the “Transmission System Network Code” (link). 

121 

            
       
 
 
 
If multiple network users submit requests to surrender capacity having the same duration, and the 
demand for capacity is lower than the total amount of capacity surrendered, the TSO will allocate 
the surrendered capacity on a first-come first-served basis. 

Long-term use-it-or-lose-it127 

The TSO must submit biannual reports on contractual congestion to the NRA, covering the periods 
from 1st April until 30th September and from 1st October until 31st March, which include at least an 
analysis of the contractual congestion during the reporting period and an analysis of the applied 
CMPs. 

In  case  contractual  congestion  is  observed,  the  TSO  must  provide  in  its  reports  to  the  NRA 
information  regarding  the  daily  utilization  of  contracted  firm  capacity  by  network  users  who 
systematically  underutilize  their  capacity.  Systematic  underutilization  of  capacity  is  defined  with 
reference to the EC CMP Guidelines.  

Upon  request  from  the  NRA,  the  TSO  must  fully  or  partially  withdraw  unused  contracted  firm 
capacity  and  promptly  notify  the  affected  network  user  of  the  withdrawal.  After  receiving  this 
notification,  the  affected  user  cannot  sell  the  withdrawn  capacity  in  the  secondary  market.  The 
withdrawn capacity must be offered without delay by the TSO to other users through the auctions 
for primary capacity at the respective IP. 

The network user, whose firm capacity has been withdrawn, retains all rights and obligations under 
the transmission contract with respect to the withdrawn capacity until it is reallocated to another 
user.  The  TSO  must  notify  the  affected  network  user  when  the  withdrawn  capacity  has  been 
reallocated.  

Management of congestion at LNG terminals128 

Terminal users are allowed to surrender their regasification capacity to the terminal operation, as 
described below.  

In the event of terminal capacity congestion129, and if a terminal user does not intend to utilize its 
LNG  regasification  capacity,  the  terminal  operator  may  offer  the  unused  capacity  at  the  primary 
capacity market. 

The procedure is initiated following notification from a terminal user that it does not intend to use 
its contracted capacity. If the notification is delivered to the operator at least 7 days prior to the 
deadline for the annual regasification capacity allocation process, the operator includes the returned 
capacity within the annual capacity booking procedure. If the user returns the capacity after the 
expiry  of  this  deadline,  then  the  returned  capacity  is  offered  as  part  of  the  short-term  capacity 
allocation process. The terminal user does not have the right to sell the returned capacity in the 
secondary market. 

The  terminal  operator  must  notify  the  user  returning  its  capacity  once  its  capacity  has  been 
reallocated.  The  user  retains  its  rights  and  obligations  in  accordance  with  the  terminal  use 
agreement, until the capacity has been reallocated. 

Management of congestion at underground storage facilities 

The SSO does not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

127 The mechanism is described in the “Transmission System Network Code”  (link). 

128 The mechanism is described in the “Rules of Operation of the LNG Terminal” (link). 

129 A situation where demand for regasification capacity exceeds the technical or available capacity at the terminal. 

122 

            
       
 
 
 
Czech Republic 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB130 

 

FDA-UIOLI 

 (all IPs) 

Surrender 

LT-UIOLI 

 

 

- 

Oversubscription and buy-back 131 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

If the technical capacity at an IP is fully booked, the TSO offers additional firm capacity at that IP. 
In  this  case,  the  TSO  announces  the  provision  of  additional  capacity  at  its  website  (capacity  is 
flagged as "oversubscription”) and makes the capacity available by 16:30 on the previous gas day. 
The additional capacity is offered through the auction booking platform.  

If the TSO cannot accommodate the nominations of network users for additional capacity at an IP, 
it initiates a buy-back procedure. The TSO notifies, via email, the network users who have booked 
capacity at the relevant IP, with details on the auction and the capacity it requests to buy back. 

Network users who have booked firm or additional firm capacity at the IP are eligible to offer all or 
part of their transmission capacity in the buy-back auction. In doing so, network users must specify 
the capacity they offer and the requested price. The requested price is capped at 1.5 times the tariff 
for daily capacity at the IP. 

The first buy-back auction is conducted at 20:00 on the day before the use of the capacity, followed 
by another auction at 00:00. Subsequently, auctions take place at every full hour, with the final 
auction  at  03:00  on  the  gas  day.  Each  auction  lasts  20  minutes,  with  results  evaluated  and 
communicated  within  5  minutes.  The  bids  are  evaluated  using  an  ascending  order  algorithm, 
according to the unit price offered by the users. For bids offered at the same price a first-come first-
served principle applies. 

The capacity will be allocated up to the total amount sought in the auction. If the TSO fails to buy 
back  all  the  required  capacity,  it  reduces  the  additional  capacity  and  respective  nominations 
proportionately to the amount of additional capacity booked by each user at the IP for the particular 
gas day, with short-term firm capacity products being reduced first. The network users do not pay 
for the amount of capacity that has been reduced by the TSO. 

In practice, the oversubscription mechanism has not been activated for any IPs. Instead, an FDA 
UIOLI mechanism is applied. 

130 Although the OS+BB mechanism is foreseen in the regulation, the FDA UIOLI has been applied in practice at the IPs. 

131 The mechanism is described in the “Network Code” (link). 

123 

            
       
 
 
 
Firm day ahead use-it-or-lose-it132 

If there is no available firm capacity at an IP, the TSO announces restrictions to the renominations 
of network users holding capacity at that network point. In such a case, the renominations at the 
IP by a user cannot: 

• 

• 

Increase  the  nominated  volumes  above  90%  of  the  user’s  booked  capacity,  if  the 
nomination submitted by the user was 80% or less of the booked capacity. 

Increase the nominated volumes above half of the difference between the capacity booked 
by the user and the nomination submitted, in the case the nomination submitted exceeded 
80% of the user’s booked capacity. 

•  Decrease the nominated volumes below 10% of the user’s booked capacity if the nomination 

submitted was 20% or more of the booked capacity. 

•  Decrease the nominated volumes below half of the difference between the capacity booked 
by user in case the nomination submitted was less than 20% of the user’s booked capacity 

The TSO notifies the users about the renomination restrictions until 09:00 on the day before these 
restrictions apply. The TSO does not accept renominations that are not in line with the above rules. 

The restrictions do not apply to users that have booked on average less than 10% of the average 
technical capacity at the IP in the previous gas year. 

Surrender of capacity133 

Network users have the right to surrender to the TSO their unused multi-annual, annual, quarterly 
or monthly firm capacity at an IP. To do so, the user submits the surrendered capacity to the TSO 
through the auction booking platform. 

The surrendered capacity is offered to the TSO in the primary market in the same manner as the 
available firm capacity but cannot be allocated as within day firm capacity. The surrendered capacity 
is reallocated to another network user only after all the available firm capacity at the IP has been 
fully booked. 

The TSO must notify the surrendering network user once the surrendered capacity has been partially 
or fully reallocated. Until the allocation is finalized, the surrendering network user retains all rights 
and obligations under the transmission contract related to the surrendered capacity. 

The network charges paid by the surrendering user are reduced by the amount paid by the network 
user who booked the surrendered capacity, including any price premia resulting from the auction. 

Long-term use-it-or-lose-it134 

The TSO must monitor the use of capacity booked by each network user for more than a year at 
IPs  border  points,  has  been  booked  for  more  than  one  year,  separately  for  the  period  from  1st 
October to  31st  March  and  from  1st  April  to  30th  September  (monitoring  periods).  The  TSO  must 
notify  the  NRA  and  the  impacted  network  user  in  case  the  user’s  capacity  at  an  IP  is  being 
underutilized.  This  notification  must  be  sent  by  the  TSO  within  one  month  from  the  end  of  the 
respective monitoring period. 

Capacity is considered as being underutilized in case: 

132 The mechanism is described in the “Gas Market Rules” (link). 

133 The mechanism is described in the “Network Code” (link). 

134 The mechanism is described in the “Gas Market Rules” (link) and in the “Network Code” (link). 

124 

            
       
 
 
 
• 

it is not used by the network user at an average level of at least 80% in two consecutive 
monitoring periods, or 

•  nominations  submitted  by  the  network  user  are  systematically  reduced  with  a  view  to 

preventing restrictions on renominations where the FDA UIOLI mechanism applies. 

The booked capacity of a user is not withdrawn, even if the above criteria apply, in case the network 
user can prove that: 

• 

• 

• 

It offered the capacity in the secondary market for a price not higher than the tariff used 
by the TSO in the primary capacity market 

It surrendered the capacity to the TSO 

The  user  requires  the  capacity  to  fulfil  its  obligations  arising  from  contracts  relating  to 
ensuring security of supply. 

Following the notification from the TSO, and in case the impacted user has not justified the non-
use  of  the  capacity,  the  NRA  may  decide  to  partially  or  fully  withdraw  any  unused  contracted 
capacity at the IP.  The withdrawn capacity must not exceed 50% of the capacity booked by the 
network user at the IP according to the transmission contract. 

The withdrawn capacity is offered to the TSO in the primary market in the same manner as the 
available firm capacity but cannot be allocated as daily or within day firm capacity. The user having 
its capacity withdrawn retains all rights and obligations associated with the withdrawn capacity until 
this is reallocated to another user. 

The network charges paid by the surrendering user are reduced by the amount paid by the network 
user who booked the surrendered capacity, including any price premia resulting from the auction. 

Management of congestion at underground storage facilities135 

A use-it-or-lose-it mechanism applies at underground storage facilities. 

The SSO must monitor the use of storage capacity by the storage users and notify the Ministry of 
Industry and Trade in case a user has booked but unused capacity. In such a case, the Ministry 
may require from the SSO to withdraw the unused capacity and offer it to the market via auctions, 
at a zero reserve price.  

The storage user that has its capacity withdrawn is not relieved from its obligation to pay its storage 
charges in accordance with the initially booked capacity.  

135 The mechanism is described in the “Energy Act” (link). 

125 

            
       
 
 
 
 
 
Denmark 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 136 

The  TSO  may  apply  an  incentive-based  oversubscription  and  buy-back  scheme  at  the  IPs  Ellund 
and Faxe at its own initiative or following request by a network user. In the latter case, the user 
must inform the TSO about its request one gas day in advance.  

The TSO determines the additional firm capacity to be oversubscribed and makes it available at the 
subsequent auctions for daily firm capacity in the relevant booking platform. Before 12:00 on the 
gas day preceding the use of capacity, the TSO must inform the users about the additional daily 
capacity offered at the auction. 

If the TSO expects that all network users utilize the entire booked capacity, including the additional 
capacity offered, then it activates the buy-back scheme. The TSO sends a notification to the network 
users, via email, informing them about the amount of capacity it seeks to buy back. Users must 
respond by 14:00 on the gas day preceding the use of capacity, with an offer including the amount 
of capacity they are willing to sell, and the respective price. The TSO must notify the users with 
successful bids by 16:00, in order for them to submit relevant renominations.  

Before applying the buy-back procedure, the TSO must examine whether alternative technical and 
commercial measures can maintain system integrity in a more cost-efficient manner.  

Surrender of capacity137 

A network user has the right to partially or fully surrender its booked capacity to the TSO Ellund 
and Faxe. Only capacity with duration of one month or more can be surrendered. Bundled capacity 
must  be  surrendered  as  bundled.  The  network  user  cannot  call  back  surrendered  capacity  and 
cannot offer it in the secondary market.  

The returned capacity is included in the available firm capacity offered by the TSO, if the network 
user surrenders it before 9:00 on the 7th gas day before the gas day when the TSO announces the 
capacities to be auctioned. If this deadline is not met, then the surrendered capacity is offered in 
subsequent  auctions  for  shorter-term  capacity.  If  several  users  surrender  capacity  for  the  same 
period, then it is offered in the market on a first-come first-served basis. 

Returned annual capacity that is not sold is re-marketed as quarterly capacity, returned quarterly 
capacity that is not sold is re-marketed as monthly capacity, and returned monthly capacity that is 

136 The mechanism is described in the “Energinet General Terms and Conditions for Gas Transport” (link). 

137 The mechanism is described in the “Energinet General Terms and Conditions for Gas Transport” (link). 

126 

            
       
 
 
 
 
not sold is re-marketed as daily capacity. Returned daily capacity that is not sold is returned again 
to the network user. 

The  network  user  retains  its  rights  and  obligations  under  the  transmission  contract  until  the 
surrendered capacity has been reallocated, or to the extent the capacity is not reallocated.  

The  user  surrendering  capacity  is  reimbursed  for  the  capacity  that  was  reallocated,  at  the 
corresponding regulated capacity tariff. 

Long-term use-it-or-lose-it138 

The TSO must regularly provide to the NRA the data necessary to monitor the use of contracted 
capacities, with an effective contract duration of more than one year or recurring quarters covering 
at least two years. 

Following a decision by the NRA, the TSO is entitled to partially or fully, reallocate any contracted 
capacity at IPs Ellund or Faxe, with a duration of more than 1 year, that is being underutilized by 
the respective network user, and this capacity was requested from other network users.  

Contracted capacity is considered systematically underutilised in particular if:  

• 

• 

The network user uses less than an average 80% of his contracted capacity both from 1st 
April  until  30th  September  and  from  1st  October  until  31st  March,  for  which  no  proper 
justification could be provided; or 

The network user systematically nominates close to 100% of his contracted capacity and 
renominates downwards. 

The above criteria do not apply in case the network user offered its unused capacity in the secondary 
market on reasonable conditions. 

Withdrawal  shall  result  in  the  network  user  losing  his  contracted  capacity  partially  or  fully  for  a 
given  period  or  for  the  remaining  effective  contractual  term.  The  user  retains  his  rights  and 
obligations under the transmission contract until has been reallocated, or to the extent the capacity 
is not reallocated. 

Other measures to manage congestion 

Over-nomination  has  been  used  by  the  TSO  as  a  mechanism  to  manage  contractual  congestion. 
This  is  capacity  allocated  within-day  implicitly,  based  on  nominations  above  booked  capacity  if 
additional capacity is available. The following principles apply: 

•  Over-nomination is activated if all firm capacity has been sold after the day-ahead or within-

day auction. 

• 

• 

• 

The  TSO  gives  higher  priority  to nominations  and  renominations  of  interruptible  capacity 
than nominations and renominations of interruptible over-nomination. 

If over-nomination has been activated on the particular time by the TSO, then a network 
user  can  implicitly  be  allocated  over-nomination  capacity  by  submitting  a  nomination 
exceeding their booked capacity. 

If  the  user  is  allocated  based  on  nominations  above  booked  firm  and/or  interruptible 
capacity, the user shall pay the capacity charge for daily capacity (firm capacity). 

138 The mechanism is described in the “Energinet General Terms and Conditions for Gas Transport” (link). 

127 

            
       
 
 
 
 
 
Management of congestion at underground storage facilities 

The SSO does not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

Use of congestion revenues 

Any revenues collected by the TSO due to auction premia are used to decrease the transmission 
system network charges.  

128 

            
       
 
 
 
 
Estonia 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

 

- 

 

 

 

- 

 

 

Oversubscription and buy-back 139 

Interface with 
LNG terminals / 
UGSs 

- 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

 

- 

 

 

When  a  network  user  submits  a  capacity  booking  application  at  an  entry  or  exit  point,  and 
contractual  congestion  occurs  at  that  point,  the  TSO  proceeds  with  assessing  statistical  data  on 
booked  and utilized  capacity  over  the  previous  period.  If  historical  analysis indicates that  not  all 
technical capacity at the given point has been fully utilized and considering potential scenarios of 
unused  capacity  for  the  designated  period,  the  TSO  offers  additional  firm  capacity  at  that  point, 
beyond the technical capacity. In offering additional capacity, the TSO must evaluate the associated 
risks and the probability of having to buy back the additional capacity that has been sold to the 
market. 

Network users wishing to book additional capacity for a gas day must submit their applications to 
the  TSO  by  08:00  UTC  on  the  gas  day  before  (or  the  last  working  day  if  the  gas  day  falls  on  a 
weekend or holiday). The TSO must calculate the available additional capacity within 2 hours and 
communicate the results to the interested network users. 

In situations where all network users intend to fully utilize their booked firm capacity at a network 
point, and the TSO is unable to meet demand for the use of the system, it must initiate the capacity 
buy-back procedure and repurchase capacity exceeding the technical limit from network users via 
the secondary market. 

The TSO notifies network users of the required buy-back quantity and the maximum price by 10:00 
UTC.  The  buy-back  price  is  capped  to  3  times  the  within-day  capacity  tariff  applicable  for  the 
particular  gas  day.  Network  users  holding  firm  capacity  products  at  that  network  point  for  the 
particular gas day may sell their capacity to the TSO by submitting an offer within 2 hours. Each 
offer must specify the volume of capacity available for buy-back and the requested price. 

The TSO may accept the users’ offers partially or in full. The TSO assesses the users’ offers on the 
basis of a lowest price priority and may buy offered capacity in full or partially. The TSO informs 
the users within 2 hours after the submission deadline. 

In  case,  following  the  capacity  buy-back  procedure,  the  TSO  is  still  unable  to  meet  all  approved 
nominations  for  firm  capacity  on  the  particular  gas  day,  it  applies  restrictions  to  firm  standard 
capacity  products.  The  shorter-term  capacity  products  (starting  with  within-day  capacity)  are 
interrupted first. If multiple firm capacity products with the same duration are affected, restrictions 
apply proportionally to the submitted nominations for the gas day. 

139 The mechanism is described in the “Common Regulations for the Use of Natural Gas Transmission System” (link). 

129 

            
       
 
 
 
 
 
Surrender of capacity140 

Network users have the right to surrender firm capacity to the TSO at an entry or exit point in case 
they are not planning to use it. The TSO shall accept the surrender of firm capacity for monthly, 
quarterly, and yearly products, as well as for daily products if the capacity has been contracted as 
bundled capacity. Capacity can be surrendered for part or the whole period of the particular capacity 
product. Interruptible capacity cannot be surrendered. 

The user interested in surrendering its capacity must submit an application to the TSO until 08:00 
UTC  on gas day previous to the use of the system. Upon receiving a capacity surrender application, 
the  TSO  publishes  information  regarding  the  quantity  of  surrendered  capacity  and  offers  the 
surrendered capacity to the market at the particular entry or exit point together with the primary 
capacity.  The  TSO  reallocates  surrendered  capacity  at  a  network  point  only  if  all  available  firm 
capacity  has  been  allocated  and  a  user  requests  firm  capacity.  Network  users  that  surrender 
capacity must refrain from actions that hinder the reallocation of this capacity. 

Until  the  surrendered  capacity  is  successfully  reallocated,  all  rights  and  obligations  under  the 
transmission  contract  remain  with  the  original  network  user.  Once  the  surrendered  capacity  is 
reallocated, the original network user is released from the payment obligation for the corresponding 
amount, starting from the shortest duration capacity product. Correspondingly, the receiving user 
must  pay  the  applicable  capacity  product  tariff  as  set  at  the  time  of  the  original  booking  by  the 
surrendering user, starting from the shortest duration capacity product. 

If multiple network users submit surrender applications at a network point for the same gas day, 
the TSO reallocates capacity on a first-come first-served basis. 

Long-term use-it-or-lose-it141 

The TSO has the right to withdraw yearly booked capacity from a network user at an entry or exit 
point, if at least one of the following conditions is met at the particular network point: 

•  The network user utilizes less than 80% of its contracted capacity on average during the 
period 1st April – 30th September and 1st October – 31st March, while having booked capacity 
with  a  duration  exceeding  one  year  and  fails  to  provide  a  valid  justification  for  the 
underutilization to the TSO. 

•  The  network  user  systematically  nominates  more  than  80%  of  its  booked  capacity  but 

subsequently renominates downwards below 80%. 

If the TSO identifies cases of underutilization based on the above criteria, it must notify the network 
user, which then has 10 calendar days to either sell the underutilized capacity on the secondary 
market or surrender the capacity to the TSO. If the network user fails to take appropriate action 
within the given timeframe, it loses the unused portion of the booked capacity. 

Until  the  TSO  successfully  reallocates  the  capacity,  the  network  user  retains  all  its  rights  and 
obligations under the transmission contract. 

140 The mechanism is described in the “Common Regulations for the Use of Natural Gas Transmission System” (link). 

141 The mechanism is described in the “Common Regulations for the Use of Natural Gas Transmission System” (link). 

130 

            
       
 
 
 
 
 
 
France 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

  

- 

 

 

- 

- 

  

 

Oversubscription and buy-back 142 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Teréga applies an OS+BB scheme at the VIPs Pirineos, in accordance with joint decision with the 
adjacent Spanish TSO. The joint decision determines the main principles for offering additional firm 
capacity  at  the  VIP  beyond  the  technical  capacity  at  the  network  point,  the  methodology  and 
procedure for calculating the additional capacity, the buy-back procedure and the pricing for the 
capacity at the VIP. The mechanism applies only to bundled capacity at the VIP. 

The TSO, in collaboration with the adjacent TSO, estimates the expected utilization of capacity at 
the  respective  VIP,  considering  factors  such  as  contracted  capacity,  scheduling,  nominations, 
historical utilization, and the risks for possible buy-back of the additional capacity. Depending on 
the expected utilization on a given gas day, the TSO may offer additional firm capacity at the VIP.  

The  additional  capacity  is  offered  as  a  daily  standard  firm  capacity  product,  together  with  the 
available  capacity  (without  any  distinctions),  at  the  respective  capacity  auction.  The  additional 
capacity  is  allocated  only  after  all  available  firm  capacity  and  any  capacity  released  through  the 
application of CMPs has been sold. 

If the total nominations at the VIP on a gas day exceed its technical capacity, and technical and 
market measures (interruption of interruptible capacities, management of the operating balancing 
account) are not sufficient to meet demand for capacity, then the TSO activates, together with the 
adjacent Spanish TSO, the buy-back procedure. The network users that have booked capacity at 
the VIP on the gas day may enter the buy-back auction, conducted at the secondary market of the 
PRISMA booking platform, and sell their capacity back to the TSOs. The TSOs must announce the 
amount of capacity that needs to be bought back, the maximum price at each side of the VIP, and 
the list of network users that can take part in the auction. At the French side, the price at which 
capacity is offered by the users cannot exceed the average of the clearing prices of the quarterly, 
monthly, and daily auction weighted by the booked quantities during these auctions, multiplied by 
a factor of 1.25143.  

The offers from the network users are ranked according to the price, with the lowest price ranking 
first. In case the capacity bought back from the users is not sufficient to cover all capacity needs at 
the  VIP,  the  TSOs  reduce  the  users’  capacity  proportionately  to  their  submitted  nominations.  In 
such a case, the TSOs must compensate the network users for the reduced capacity, using the daily 
reference price applied on that gas day. 

142 The mechanism is described in the “Enagás and TIGF (2017) Procedure for the implementation of the oversubscription and 

buy-back scheme” (link). 

143 If no daily products are offered by the TSO, then the regulated tariff for the corresponding daily product. 

131 

            
       
 
 
 
Surrender of capacity144 

Firm capacity can be surrendered by the network users at the IPs of both NaTran (former GRTGaz) 
and Teréga. The surrendered capacity can have a duration of one or more months. Surrendered 
capacity cannot be offered by the user at the secondary market.   

The surrender rules are slightly different for the two TSOs: 

•  NaTran (former GRTGaz): surrendered capacity is offered in the primary market as monthly 
firm capacity. The users must apply for surrendering capacity at least 10 days before the 
publication date of the monthly auction. 

• 

Teréga:  surrendered  capacity  is  offered  in  the  primary  market  as  quarterly  (up  to  four 
consecutive  quarters)  and  monthly  firm  capacity.  The  users  must  apply  for  surrendering 
capacity before the 1st day of the previous month. 

The  user  surrendering  its  capacity  retains  its  rights  and  obligations  until  the  capacity  has  been 
reallocated.  The  user  has  the  obligation  to  pay  the  difference  (if  positive)  between  the  payment 
that the TSO would have received if it had not allocated the surrendered capacity, and the charges 
that the TSO will receive for the reallocated surrendered capacity.  

If  more  than  one  network  user  surrender  their  capacity,  this  is  reallocated  on  a  first-come  first-
served basis. 

Long-term use-it-or-lose-it145 

The  TSOs  apply  the  LT  UIOLI  mechanism  at  their  IPs,  to  make  available  capacity  that  has  been 
booked but unused by network users. The mechanism is activated if the following conditions apply: 

• 

• 

For two consecutive six-month periods, starting on 1st October and on 1st April, the daily 
nominations of a network user are on average below 80% of its booked capacity at the IP, 
that has been allocated to the user with an effective duration of more than one year, that 
has not been transferred to another user, and 

The TSO has not been able to meet at least one request of another network user for annual 
capacity at the IP. 

When  the  TSO  received  a  request  for  capacity  from  a  user,  triggering  the  conditions  above,  it 
investigates whether one or more network users intend to surrender their capacity at the IP. The 
TSO then informs the NRA of the situation, and a proposal to withdraw a user’s capacity, if required. 

Following  the  TSO’s  notification,  the  involved  network  user  must  provide  a  justification  for  the 
underutilization of its booked capacity, within 10 working days. Taking into account this justification, 
the  NRA  decides  whether  capacity  should  be  withdrawn.  The  amount  of  capacity  withdrawn 
corresponds to the capacity requested by other network users at the IP. 

The user having its capacity withdrawn, retains its rights and obligations until the capacity has been 
reallocated.  The  user  has  the  obligation  to  pay  the  difference  (if  positive)  between  the  payment 
that the TSO would have received if it had not allocated the withdrawn capacity, and the charges 
that the TSO will receive for the reallocated capacity.  

144 The mechanism is described in the “GRTGaz Network Transmission Contract – Section B” (link) and the “Terega – Capacity 

Return Mechanism” (link). 

145 The mechanism is described in “GRTGaz Network Transmission Contract – Section B” (link) and the “Terega – Natural Gas 

Transmission Contract” (link). 

132 

            
       
 
 
 
Other measures to manage congestion146 

The  TSOs  offer  an  alternative  service,  called  Use-it-and-Buy-It  (UBI),  to  maximize  the  use  of 
capacity  in  their  system.  This  service  makes  it  possible  to  offer  day-ahead  and  within-day  any 
capacity  that  has  been  booked  but  left  unused  (non-nominated)  to  other  network  users,  as 
interruptible capacity. The UIB allows the TSOs to directly offer the aggregate unused capacity to 
the  market,  providing  a  straightforward  way  for  the  capacity  to  be  allocated.  NaTran  (former 
GRTGaz offers UBI capacity at its entry and exit IPs and at the entry from the Dunkirk LNG terminal, 
while Teréga offers it at the VIP Pirineos and Lussagnet UGS.  

The key principles of the UBI product are the following: 

• 

The TSO may offer capacity via UBI only when nearly147 all firm capacity at the network 
point has been booked. 

•  At each nomination / renomination cycle, the TSO determines the unused firm capacity that 
can  be  offered  via  the  UBI,  as  the  difference  between  the  operational  capacity  of  the 
network point and the aggregate nominations of all network users. The offered UBI capacity 
is posted by the TSO at its electronic platform. 

• 

To  request  UBI  capacity,  network  users  submit  nominations  exceeding  their  firm  booked 
capacity. The requested UBI includes the interruptible capacity requested by the user (UBI 
request within the capacity rights), and additional capacity requested (UBI request above 
the capacity rights). 

•  UBI capacity is allocated at the end of each nomination/renomination cycle. If the requests 
for UBI capacity exceed the offer, then UBI capacity within the users’ rights is allocated first 
and UBI above the capacity rights is allocated afterwards. UBI requests are allocated on a 
pro-rata basis.  

• 

If the primary owners of capacity re-nominate during the following cycles the use of UBI 
capacity is partially or fully restricted. (the firm capacity holders’ right to nominate is thus 
not withdrawn from them, capacity being reallocated via UBI on an interruptible basis only). 

Management of congestion at LNG terminals148 

Use-it-or-lose-it and surrender mechanisms apply at the LNG terminals. 

At the terminals of Fos-Tonkin, Montoir-de-Bretagne and Fos-Cavaou, a terminal user may inform 
the operator that it wants to remove from its annual schedule all or part of its booked capacities 
until  the  month  before.  The  terminal  operator  must  publish  these  capacities,  as  available  firm 
capacity and make them available to the market.  

At these terminals, if the schedule for a month does not show any available firm capacity, but an 
unloading is cancelled (for reasons other than force majeure), the terminal operator must report 
the  situation  to  the  NRA.  The  NRA  may  request  withdrawal  of  the  respective  user’s  capacity,  in 
order to make this capacity available at the terminal. 

A  surrender  mechanism  applies  at  the  LNG  terminal  in  Le  Havre.  The  terminal  users  have  the 
obligation  to  return to the  operator  slots  at the  terminal they  do  not intend to  use,  at  least  one 
month  before  their  use.  The  operator  offers  the  slots  for  sale,  at  a  reserve  price  defined  by  the 

146 The mechanism is described in the “The UBI (Use-it-and-buy-it) capacity offer” (link). 

147 A threshold of 98% of booked capacity applies. 

148 These mechanisms are described in the “FRAMEWORK CONTRACT FOR ACCESS TO MONTOIR-DE-BRETAGNE or FOS 

TONKIN LNG TERMINAL” (link) and  in the Commission Decision (31/3/2023) on the exemption of LNG Terminal in Le Havre 
(link). 

133 

            
       
 
 
 
surrendering terminal user, which is capped to the base tariff for the slot. The slots are sold to the 
user offering the highest price. 

Management of congestion at underground storage facilities 

The SSOs do not apply specific measures to manage contractual congestion at their underground 
storage facilities. Yet, the mechanisms offered at transmission-storage points (‘PITS’) play a role in 
contractual congestion management, in particular the UBI offer. 

Use of congestion revenues 

Revenues  of  the  TSO  resulting  from  auction  premia  are  part  of  the  over-recovery  of  the  TSOs’ 
regulated  revenues,  which  is  included  in  their  clawback  account  (‘compte  de  régularisation  des 
charges et des produits – CRCP’) and is returned to network users over the following years. 

134 

            
       
 
 
 
 
 
Germany 

Overview of CMP Guidelines application 

CMP 

IPs 
with 
Member 
States 

IPs with 
third 
countries 

Interface 
with LNG 
terminals 
/ UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB149 

FDA-UIOLI 

Surrender 

LT-UIOLI 

- 
 (all 
IPs) 
 

 

- 

 

 

 

- 

- 

 

 

- 

- 

- 

- 

- 

- 

 

 

Firm day ahead use-it-or-lose-it150 

All the German TSOs apply the same FDA UIOLI mechanism, in accordance with the provisions of 
the  standard  capacity  contract  (Annex  1  KoV).  The  mechanism  applies  at  all  IPs,  regardless  of 
whether they have been identified as congested in the ACER Congestion Report. 

The FDA UIOLI mechanism sets restrictions on the renominations for firm capacity that the network 
users can submit at the IPs:  

•  Renomination is permitted up to 90% of the firm capacity booked by the user at the IP, 

subject to a minimum of 10% of the booked capacity.  

• 

• 

In  the  case  the  initial  nomination  exceeds  80%  of  the  firm  booked  capacity,  the  user  is 
allowed to renominate upward up to half of the non-nominated booked capacity.  

In  the  case  the  initial  nomination  is  below  20%  of  the  firm  booked  capacity,  the  user  is 
allowed to renominate downward of up to half of the nominated booked capacity.  

Renominations for firm capacity exceeding the amount permitted are accepted up to the amount of 
total booked capacity. The part of the renomination which exceeds the quantity permitted is treated 
as a nomination of interruptible capacity and is interrupted first. 

The  TSO  determines  the  renomination  limits  after  14:00,  based  on  the  booked  capacity  of  each 
user. The daily and within-day capacity booked by the users is disregarded when the permissible 
renomination  range  is  set.  The  TSO  offers  the  released  capacity  as  firm  capacity  in  the  primary 
market. 

The renomination restriction does not apply to network users who have booked less than 10% of 
the yearly technical capacity at the IP on a firm basis. 

149 An OS+BB scheme is used in Germany  as of October 2021, aimed at making additional firm capacity available after the 

merger of GASPOOL and NCG into a single market area, the Trading Hub Europe. As the mechanism was not used to manage 
short-term contractual congestion, it is not analysed in this study. 

150 The mechanism is described in the “OGE General Terms & Conditions for Entry/Exit Contracts” (link). The same mechanism 

is applied by all TSOs. 

135 

            
       
 
 
 
Surrender of capacity151 

The same surrender procedure is applied by all the German TSOs at their network points, except 
offtakes to consumers. Bundled capacity can only be surrendered as bundled capacity. 

The surrendered capacity is offered by the TSO in the primary market. The TSO has the right to 
combine surrendered capacity with any available capacity at the network point, to offer products of 
longer  duration.  If  a  user  surrenders  capacity  by  09:00  on  the  7th  day  prior  to  the  day  of  the 
notification of the amount of the capacity offered in an annual, quarterly, or monthly auction, the 
TSO includes this surrendered capacity in the relevant auction. At the latest, a user must surrender 
its capacity until 14:00 on the day prior to the use of this capacity.  

The network user is released from its obligation to pay network charges for the surrendered capacity 
once this capacity has been reallocated to another user. Nevertheless, the user has to pay for the 
difference between the tariff at which the capacity was initially booked and the price at which it was 
reallocated. Furthermore, the user retains its obligation to pay for any auction premia that resulted 
when capacity was initially booked.  

If more than one network user surrender capacity for the same period at the same network point, 
the TSO reallocates the capacity on a first-come first-served basis.  

Long-term use-it-or-lose-it152 

The same LT UIOLI mechanism is applied by all the German TSOs at their entry and exit points.  

At  network  points  other  than  cross-border  IPs,  in  the  event  of  contractual  congestion  (network 
access is denied to a user due to lack of capacity), the TSO must withdraw a network user’s firm 
booked capacity with duration of at least one year, if the user did not use the capacity regularly for 
three months within the previous calendar year. One of these months must be October, November, 
December,  January,  February  or  March.  The  user’s  capacity  released  corresponds  to  the 
continuously unused part of the capacity for the examined 3-month period. 

The user can object to the withdrawal, if it proves that: 

• 

• 

• 

The unused capacity was offered in the secondary market or was surrendered to the TSO. 

The unused capacity is required to meet its contractual obligations. 

It holds supply contracts for which capacity is booked at different entry points that are being 
used alternatively. 

If capacity must be withdrawn from several network users, the withdrawal is proportional to the 
booked capacity of each user at the network point. 

At the cross-border IPs, the TSO must withdraw capacity if required by the NRA. The TSOs must 
regularly provide the NRA with all data necessary to monitor the extent to which booked capacities 
under contracts, with an effective duration of more than one year or succeeding quarters covering 
at least two years, are being used.  

The network user is released from its obligation to pay network charges for the withdrawn capacity 
once this capacity has been reallocated to another user. Nevertheless, the user has to pay for the 
difference between the tariff at which the capacity was initially booked and the price at which it was 

151 The mechanism is described in the “OGE General Terms & Conditions for Entry/Exit Contracts” (link). The same mechanism 

is applied by all TSOs.  

152 The mechanism is described in the “OGE General Terms & Conditions for Entry/Exit Contracts” (link). The same mechanism 

is applied by all TSOs.  

136 

            
       
 
 
 
reallocated. Furthermore, the user retains its obligation to pay for any auction premia that resulted 
when capacity was initially booked.  

Management of congestion at LNG terminals153 

A UIOLI mechanism applies for managing congestion of the LNG terminals’ capacity.  

At the regulated LNG terminals, the terminal user must notify the operator that it is not planning 
to use its unloading slot at least 20 days in advance. If the user does not notify the operator, or it 
does not designate another user to whom the capacity is transferred, the terminal operator activates 
the UIOLI mechanism. The terminal operator must publicly announce the released capacities and 
allocate them following a transparent and non-discriminatory procedure. If the released capacity 
has not been reallocated within 3 days from its announcement, it is returned to its initial owner.  

The UIOLI mechanism is similar at the exempted LNG terminals154. 

Additionally, a surrender mechanism is applied at the LNG terminals. 

Management of congestion at underground storage facilities155 

A  UIOLI  mechanism  applies  to  manage  congestion  of  storage  capacity  at  the  underground  gas 
storages,  linked  to  the  fulfilment  of  the  storage  level  requirements  that  are  set  in  the  national 
legislation. 

If the storage filling obligations cannot be met because one or more storage users hold booked but 
unused  capacity,  then  the  SSO  can  make  this  capacity  available  to  the  market  area  manager, 
including the respective injection and withdrawal capacity. The capacity released from each user is 
proportional to its booked capacity. 

The storage user having its capacity withdrawn is not released from the obligation to pay its storage 
charges, with the exception of variable fees for injection and withdrawal. 

Use of congestion revenues 

Additional  revenues  of  the  TSO,  including  congestion  revenues,  can  generally  be  used  for  tariff 
reductions and for funding investments to enhance the capacity of the system. Typically, these are 
included in the regulatory account and used for lowering tariffs for the next period. 

153 The mechanism is described in the Section 5 of the “Regulation on the regulatory framework for LNG plants (LNGV)” (link). 

154 See for example the Commission Decision (20/12/2022) on the exemption of LNG Terminal in Lubmin (link). 

155 The mechanism is described in the Section 35b of the “German Energy Industry Act (EnWG)” (link). 

137 

            
       
 
 
 
 
 
 
Greece 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB 

 

FDA-UIOLI   (congested 

Surrender 

LT-UIOLI 

IPs) 
 

 

 

- 

 

 

Oversubscription and buy-back 156 

- 

- 

 

 

- 

- 

 

 

- 

- 

 

 

The operator of the Greek national transmission system can offer additional firm capacity through 
oversubscription at the entry IPs with other EU Member States and third countries (entry from the 
LNG  terminal  is  excluded).  The  TSO  must  publish  at  its  electronic  platform  the  methodology  for 
calculating the additional capacity to be offered at an entry point. When determining the additional 
capacity, the TSO must take into account historical data on the gas deliveries at each entry point, 
the maintenance plans and the reliable, safe and efficient operation of the transmission system. 

The TSO must publish at its electronic platform information regarding the offering of additional firm 
capacity (if any), including a justification for its calculation, at least 5 days before each month. The 
additional  capacity  is  sold  after  all  available  firm  capacity  at  the  particular  entry  point  has  been 
allocated. 

If  the  additional  transmission  capacity  for  delivery  has  been  booked  at  an  entry  point  and  the 
nominations of network users indicate that the gas deliveries are expected to exceed the technical 
limitations of the entry point, the TSO may initiate a buy-back procedure. This procedure allows 
network users that have booked capacity and submitted nominations at the particular entry point 
on that gas day, to sell part of their booked capacity back to the TSO. The amount of capacity they 
can sell is limited to their confirmed quantities for the entry point on that gas day. 

The TSO announces the buy-back start time via its electronic platform at least 1 hour before the 
buy-back  procedure  is  initiated.  The  TSO  must  inform  the  network  users  about  the  requested 
capacity to be bought back, the unit price at the start of the process and the maximum buy-back 
price. The maximum buy-back price corresponds to a multiple of 1.5 of the yearly tariff applied at 
the network point. 

Each user may submit one offer within 30 minutes of commencement of the buy-back procedure. 
Offers consist of the amount of capacity the network user is offering and a buy-back offer unit price 
(between the initial and maximum unit prices defined by the TSO). The offers are ranked on the 
basis of the offered unit price. After the network users have submitted their offers, the offers are 
ranked in an ascending order based on their unit price: 

• 

• 

If  the  total  offered  capacity  matches  the  required  buy-back  capacity,  all  valid  offers  are 
accepted at the submitted unit price. 

If the total offered capacity exceeds required buy-back capacity: 

o 

Lower-ranked offers are accepted fully. 

156 The mechanism is described in the “Network Code Of The Hellenic Gas Transmission System” (link). 

138 

            
       
 
 
 
o  The highest-ranking offer is partially accepted to match the required capacity. 

• 

If the lowest priced offer alone meets or exceeds the required buy-back capacity, it is fully 
accepted at the offered unit price. 

If  the  total  offered  capacity  is  insufficient,  the  remaining  buy-back  capacity  is  proportionally 
allocated among all network users based on their confirmed quantities. 

Non-participating  users  are  assigned  a  buy-back  price  equal  to  the  initial  buy-back  unit  price. 
Participating users receive a weighted average price based on their submitted price and the initial 
buy-back unit price. If no valid offers are received, the buy-back capacity is allocated proportionally 
among the network users based on their confirmed quantities.  

Firm day ahead use-it-or-lose-it157 

The FDA UIOLI mechanism is in place at the two interconnectors, IGB and TAP. The mechanism is 
activated only at the IPs which have been identified as congested, in accordance with the criteria 
of the CMP Guidelines. 

Once the mechanism is activated at an IP, the following restrictions apply to the renominations of 
network users at that point: 

• 

• 

• 

The network user may renominate between 90% and 10% of its booked capacity. 

If  the  nomination  exceeded  80%,  the  network  user  can  renominate  upwards  up  to  a 
maximum of half of the non-nominated quantity. 

In the nomination was below 20%, the network user can renominate downwards up to half 
of its nominated quantity. 

The network users are allowed to use the restricted part of their booked capacity on an interruptible 
basis.  

The above restrictions do not apply to network users holding less than 10% of the average technical 
capacity at the IP in the previous gas year. 

Application of the FDA UIOLI restrictions may be terminated if the congestion at the relevant IP is 
unlikely to re-occur in the subsequent 3 years. 

Surrender of capacity158 

Network users may surrender to the TSO all or part of their booked firm capacity at a network point, 
for capacity that has been booked for a period longer than a day. The surrendered capacity is made 
available by the TSO to other network users through the primary capacity market. The TSO does 
not  accept  surrender  of  capacity  that  is  being  offered  by  the  network  at  the  secondary  capacity 
market. 

Any surrendered bundled capacity must be reallocated as bundled capacity. At the entry points from 
LNG terminals, the surrender of firm capacity must be conducted together with the corresponding 
LNG regasification capacity. 

To  surrender  capacity,  the  network  users  must  submit  an  application  to  the  TSO  specifying  the 
amount of capacity surrendered and the start and end date for which capacity is being returned to 
the  TSO.  The  end  date  cannot  extend  the  duration  of  the  respective  capacity  booking.  The 
application  must  be  submitted  by  08:00  on  the  day  preceding  the  requested  start  date  of 
surrendering the capacity.  

157 The mechanism is described in the “IGB Network Code” (link) and the “Trans Adriatic Pipeline Network Code” (link). 

158 The mechanism is described in the “Network Code Of The Hellenic Gas Transmission System” (link). 

139 

            
       
 
 
 
The  network  user  retains  all  its  financial  rights  and  responsibilities  related  to  the  surrendered 
capacity  under  the  transmission  contract  until  this  capacity  has  been  reallocated  by  the  TSO  to 
another user.  

If  multiple  network  users  submit  surrender  requests  for  the  same  entry  or  exit  point,  the  TSO 
allocates them on a first-come first-served basis. 

Long-term use-it-or-lose-it159 

The TSO may withdraw capacity at a network point that has been booked by a network user for a 
period of more than a year, if the following conditions are both met: 

• 

• 

There is a request to book capacity at the network point, but the available capacity is not 
sufficient to satisfy the demand, and 

The average utilization (including surrendered capacity and capacity sold at the secondary 
market)  over  the  preceding  twelve  months  is  below  80%  of  the  booked  capacity  at  the 
relevant point. 

The  TSO  must  inform  the  NRA  of  its  decision  and  provide  information  to  the  NRA  regarding  the 
utilization  of  the  network  point  by  the  network  user  for  the  past  3  months.  If  the  information 
provided by the TSO indicates underutilization of the network point, the NRA may require from the 
TSO to ask from the network user to provide justification for not using its booked capacity, within 
a period of 15 days. 

If a network user fails to adequately justify their underutilization in due time, the TSO may release 
a portion of the booked capacity, which is the maximum between the amount of average unused 
capacity and 0.2% of the booked capacity at the network point. 

The first capacity withdrawal applies for 30 days. Each subsequent withdrawal doubles the duration 
for the same user. If a network user undergoes 4 capacity withdrawal within a 48-month period at 
the same point, the remaining booked capacity for that period is fully withdrawn. 

The network user retains all its financial rights and responsibilities related to the withdrawn capacity 
under the transmission contract until this capacity has been reallocated by the TSO to another user.  

Management of congestion at LNG terminals160 

A  UIOLI  mechanism  applies  for  the  regasification  capacity  booked  by  terminal  users  at  the 
Revythoussa LNG terminal161. 

The terminal operator may release regasification capacity of a terminal user for a period of time, in 
case  no  unloading  of  LNG  quantities  are  planned  for  that  period  and  other  terminal  users  have 
requested  regasification  capacity  from  the  operator.  Withdrawal  of  the  regasification  capacity  is 
carried out jointly with withdrawal of capacity at the transmission entry point from the LNG terminal.  

Furthermore, the terminal operator can withdraw capacity booked by a terminal user, in case: 

• 

The user is systematically underutilizing its capacity. Systematic underutilization is defined 
as the case in which the average use of capacity for a period of 6 consecutive months is 
less than 80% of the average booked capacity for the same period. 

159 The mechanism is described in the “Network Code Of The Hellenic Gas Transmission System” (link). 

160 The mechanisms are described in the “Network Code Of The Hellenic Gas Transmission System” (link) and the “Gastrade – 

Alexandroupolis LNG Terminal Access Code” (link). 

161 A UIOLI mechanism also applies for the additional and temporary storage services. Furthermore, the terminal users also 
have the right to surrender their booked additional and temporary storage, provided that this is not being offered at the 
same time at the secondary market. 

140 

            
       
 
 
 
• 

• 

The underutilization is adversely affecting the ability of other user to access the terminal, 
the economic efficiency or the terminal, and security of supply. 

The terminal user has failed to offer the unused capacity in the secondary market for at 
least 70% of the time during which the average utilisation was below 80%. 

In case the above criteria apply, the terminal operator may, following request from the NRA, ask 
from the terminal user to provide justification for not using its booked regasification capacity, within 
a period of 15 days. 

If a user fails to adequately justify their underutilization in due time, the terminal operator must 
release at least 20% of the user’s booked regasification capacity within the next month. The capacity 
is released for a period of the total temporary storage period for the booked capacity, plus 2 days. 

The terminal user retains all its financial rights and responsibilities related to the withdrawn capacity 
under the transmission contract until this capacity has been reallocated by the operator to another 
user.  

At the Alexandroupolis LNG terminal users with long-term capacity rights are entitled to surrender 
their  unused  capacity.  This  capacity  is  made  available  by  the  terminal  operator  to  other parties, 
once the available capacity at the terminal has been allocated. In case the surrendered capacity 
has been sold, the terminal user must pay an administrative fee to the operator.   

Use of congestion revenues 

Congestion revenues are used to reduce the tariffs for the use of the transmission system. These 
revenues are part of the regulated revenues of the TSO. 

141 

            
       
 
 
 
 
 
 
Hungary 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB162 

 

FDA-UIOLI   (congested 

Surrender 

LT-UIOLI 

IPs) 
 

 

 

- 

 

 

Oversubscription and buy-back 163 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

To offer additional firm capacity at an IP, beyond the technical capacity of the point, the TSO must 
submit  to  the  NRA  a  proposal  for  an  incentive-based  oversubscription  and  buy-back  scheme. 
Following  approval  by  the  NRA,  the  TSO  must  apply  the  scheme  before  the  beginning  of  the 
subsequent gas year. The mechanism must be developed so that the TSO and the network users 
share  the  revenues  from  the  allocation  of  the  additional  capacity  and  the  costs  from  a  potential 
buy-back. 

When determining the additional firm capacity, the TSO must consider statistical scenarios related 
to physically unused capacity at the IPs at various times and the risk profiles of having to buy back 
the  additional  capacity.  The  additional  capacity  is  offered  by  the  TSO  in  the  primary  market, 
together with the available firm capacity at the IP. The available firm capacity at the IP, as well as 
any  surrendered  capacity  and  capacity  withdrawn  through  the  application  of  the  LT  UIOLI 
mechanism, must be sold before the allocation of the additional firm capacity. 

In case the allocation of additional firm capacity puts the integrity of the transmission system at 
risk,  the  TSO  activates  a  transparent  and  market-based  buy-back  procedure,  allowing  network 
users to sell their capacity back to the TSO. Before activating this procedure, the TSO must first 
apply alternative technical or commercial measures to maintain the system’s integrity. 

In practice, the TSO has not submitted an oversubscription and buy-back scheme to the NRA for 
any IP. Instead, an FDA UIOLI mechanism is applied. 

Firm day use-it-or-lose-it164 

An FDA UIOLI mechanism applies at the IPs with EU Member States, which have been identified as 
congested in ACER’s Congestion Report. Under this mechanism, renomination restrictions apply to 
the long-term, quarterly, and monthly firm (including conditional) capacities of network users at 
the  particular  IP.  These  restrictions  will  be  determined  separately  for  each  hour  of  the  gas  day 
based on the firm capacities available for that hour and the nominations submitted.  

The following restrictions apply: 

• 

For users nominating between 20% and 80% of their contracted capacity, renomination is 
allowed up to a maximum of 90% and a minimum of 10% of the contracted capacity. 

162 Although the OS+BB mechanism is foreseen in the regulation, the FDA UIOLI has been applied in practice at the IPs. 

163 The mechanism is described in “Operation and Business Code of the Hungarian Natural Gas System” (link). 

164 The mechanism is described in “Operation and Business Code of the Hungarian Natural Gas System”  (link). 

142 

            
       
 
 
 
• 

• 

For users nominating more than 80% of their contracted capacity, renomination is allowed 
up  to  a  maximum  of  half  of  the  non-nominated  capacity  and  a  minimum  of  10%  of  the 
contracted capacity. 

for users nominating up to 20% of their contracted capacity, renomination is allowed up to 
a maximum of 90% and a minimum of half of their nomination. 

The  restrictions  will  be  applied  in  the  following  order:  first  to  long-term  capacities,  followed  by 
annual, quarterly, and monthly firm capacities. If both bundled and non-bundled firm capacities are 
available to the network user for a specific capacity type, the restrictions will be applied on a pro-
rata basis. 

Network users may renominate the restricted part of their booked capacity on an interruptible basis. 
The users having their capacity interrupted due to the restrictions of the FDA mechanism are not 
entitled to reimbursement or tariff discount due to this interruption. 

The TSO must notify the network users about the restrictions at each IP by 16:00 one gas day in 
advance.  These  restrictions  are  based  on  the  nominations  submitted  by  the  users  by  14:00  and 
their booked capacities. 

The  restrictions  do not  apply  to network  users  that hold  less than  10%  of  the  average  technical 
capacity at the IP in the preceding gas year.  

Network  users  will  not  be  entitled  to  a  reimbursement  of  capacity-based  transmission  tariffs  or 
nomination imbalance surcharges due to the application of renomination restrictions. Additionally, 
if  the  interruptible  capacity  offered  during  the  restriction  is  interrupted,  no  fee  discount  will  be 
provided. 

Surrender of capacity165 

Network users have the right to surrender their booked firm capacity (including conditional) to the 
TSO at an IP, except for daily and within-day capacity products. Bundled capacities may only be 
surrendered as bundled capacities. Surrendered capacities cannot be sold by the network user in 
secondary capacity markets and cannot be transferred to another network user. 

The TSO offers the surrendered capacity in the daily auction for firm capacity, provided that the 
capacity is surrendered before 00:00 on the working day before the announcement of the auction’s 
capacity.  The  surrendered  capacity  is  allocated  only  after  available  capacity  at  the  IP  (including 
conditional) has been sold.  

The network user retains the rights and obligations under the transmission contract until the TSO 
reallocates  the  surrendered  capacity,  either  partially  or  in  full.  The  TSO  is  required  to  promptly 
notify  the  network  user  once  any  part  of  the  surrendered  capacity  has  been  resold.  The  user 
surrendering the capacity does not receive any revenue from the auction premium (if any) when 
the capacity has been sold by the TSO. 

In  case  multiple  network  users  have  surrendered  their  capacity  on  the  same  day,  the  TSO 
reallocates this capacity on a first-come first-served basis. 

165 The mechanism is described in “Operation and Business Code of the Hungarian Natural Gas System” (link). 

143 

            
       
 
 
 
 
 
 
 
Long-term use-it-or-lose-it166 

The TSO must notify the NRA in case it identifies cases where a network user, holding firm capacity 
exceeding  one  year  at  an  IP,  is  systematically  underutilizing  its  booked  capacity.  Capacities  are 
deemed to be systematically underutilized under either of the following circumstances: 

1.  The network user utilizes, on average, less than 80% of its booked capacity during both in 
the periods from 1st April to 30th September and from 1st October to 31st March, without 
providing adequate justification, or 

2.  The network user’s initial nomination frequently exceeds 80% of the booked capacity, but 
the final nomination following renominations for the same gas day fall below 80% of the 
booked capacity. 

In its notice to the NRA, the TSO indicates whether other network users have submitted requests 
for firm capacity at the IP, which could not be covered due to the lack of available capacity. Upon 
the NRA’s request, the network user must, within 5 days, demonstrate that the unused capacity 
has  been  offered  for  sale  in  the  secondary  market  under  reasonable  conditions,  or  provide  a 
justification for its non-utilization. The network user can surrender its systematically underutilized 
capacity to the TSO. 

If the user fails to justify the underutilization of capacity, the NRA issues a decision requiring the 
TSO  to  withdraw  the  user’s  capacity  and  offer  it  in  the  primary  market.  The  TSO  allocates  the 
withdrawn capacity only after other available capacity (including conditional) at the IP have been 
sold. If the TSO has withdrawn capacities from multiple users, then the capacities withdrawn earlier 
are allocated first. Withdrawn capacities cannot be sold by the network user in secondary capacity 
markets and cannot be transferred to another network user.  

The network user retains the rights and obligations under the transmission contract until the TSO 
reallocates the withdrawn capacity, either partially or in full. The TSO is required to promptly notify 
the  network  user  once  any  part  of  the  withdrawn  capacity  has  been  resold.  The  user  having  its 
capacity  withdrawn  does  not  receive  any  revenue  from  the  auction  premium  (if  any)  when  the 
capacity has been sold by the TSO. 

Management of congestion at underground storage facilities 

The SSOs do not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

Use of congestion revenues 

The decision regarding the use of the congestion revenues is in the competence of the NRA, that 
decides  whether  these  revenues  will  be  used  to  decrease  network  charges  or  to  invest  in  the 
transmission network. 

166 The mechanism is described in “Operation and Business Code of the Hungarian Natural Gas System” (link). 

144 

            
       
 
 
 
 
 
Ireland 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

- 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 167 

The  TSO  must  develop  and  submit  to  the  NRA  an  oversubscription  and  buy-back  scheme,  to  be 
applied at a contractually congested IP. 

Once an IP is identified as congested, the TSO calculates on a daily basis the amount of additional 
firm  capacity  that  can  be  made  available  at  that  network  point.  Depending  on  the  prevailing 
circumstances the TSO may offer no additional capacity at the IP. Additional capacity is offered as 
daily firm capacity, and is sold at the primary market, and should be indistinguishable from any 
other  primary  capacity  booked  by  a  network  user.  The  TSO  notifies  the  users  of  the  additional 
capacity available for the next gas day until 14:00. 

Every quarter the TSO should inform the network users of the total amount of additional capacity 
made available during the previous quarter, and the amount of this that was booked. 

When additional capacity is made available at a congested IP, the TSO may purchase firm capacity 
from network users to maintain the operational integrity of the transmission system. To initiate the 
buy-back tender process, the TSO invites network users to submit offers for selling firm capacity to 
the TSO at the specific IP168. The TSO’s invitation defines, inter alia, the total amount of capacity 
the TSO is looking to buy, and the minimum amount of capacity a user can offer. Such an invitation 
can be published by the TSO until 18:00 on the day that capacity is requested. 

Network  users  interested  in  selling  their  firm  capacity  may  respond  to  a  buyback  invitation  by 
submitting  a  buyback  offer,  in  which  they  define  the  amount  of  capacity  they  offer  and  the 
corresponding unit price. The TSO may accept the buyback offers in whole or in part. 

If the TSO does not manage to buy enough capacity back to ensure the operational integrity of the 
system, it can proceed with applying measures for managing physical congestion at the IP. 

Surrender of capacity169 

Once an IP has been identified as contractually congested, the TSO informs the network users that 
they  may  submit  requests  for  surrendering  capacity.  A  network  user  has  the  right  to  surrender 
yearly, quarterly or monthly firm capacity. In such a case, the user informs the TSO, inter alia, of 
the total and minimum amount of capacity it is willing to surrender and the period for which the 
surrendered  capacity  will  be  available  (a  full  calendar  month  or  a  series  of  consecutive  calendar 

167 The mechanism is described in the “Code of Operations part H” (link). 

168 The TSO may sign advance buy-back agreements with network users, committing them to sell at an agreed price.  

169 The mechanism is described in “Code of Operations part H” (link). 

145 

            
       
 
 
 
months).  Capacity  can  be  surrendered  at  an  IP  within  a  window  of  7  calendar  days,  starting  2 
months before the validity of the released capacity starts. 

A network user surrendering its capacity retains its rights and obligations related to the capacity 
surrender  available  amount,  until  this  capacity  has  been  reallocated.  If  multiple  users  surrender 
their capacity, the TSO reallocates it on a first-come first-served basis. 

Long-term use-it-or-lose-it170 

The TSO must monitor the utilization of yearly or quarterly firm capacity booked by network users 
at IPs and prepare relevant monitoring reports. Each monitoring report covers one of two six-month 
periods: from 1st October to 31st March or from 1st April to 30th September (each referred to as a 
"monitoring  period").  The  TSO  must  submit  the  monitoring  report  to  the  NRA  within  six  weeks 
following the end of each monitoring period. 

Based on the information in the monitoring reports the TSO must make a preliminary assessment 
of whether a network user is systematically underutilizing its booked capacity at an IP. Capacity is 
considered as systematically underutilized if it has been booked for a long-term period and in each 
of 2 consecutive monitoring reports the nominations at the IP for this capacity were on average less 
than 80% of the user’s average capacity. 

The TSO notifies a network user with systematically underutilized capacity, so that the latter can, 
within 1 month: 

• 

• 

Justify the non-utilization of its capacity. 

Provide evidence that it offered the capacity under reasonable conditions in the secondary 
market, in an advance buyback agreement or surrendered it to the TSO. 

•  Accept  that  the  capacity  was  systematically  underutilized  and  propose  to  reduce  the 

withdrawable capacity. 

If the TSO considers that the response dees not provide sufficient justification, then it notifies the 
user that the response is not accepted. The user can then refer this rejection to the NRA within 10 
days from its receipt, so that the NRA can decide whether the justification provided is sufficient or 
not.  

In case the network user has not provided a response to the TSO’s notice, or the user’s response 
is deemed unsatisfactory by the TSO (and potentially the NRA), then the TSO may withdraw the 
user’s capacity, up to the difference between the systematically underutilized capacity and the peak 
daily allocation of the user increased by 5%. Capacity can be withdrawn no earlier than 3 months 
after the network user was notified about the underutilized capacity. The period for which capacity 
is withdrawn can be a number of consecutive days, a month or consecutive months. 

Withdrawn capacity is offered by the TSO in the relevant auction for firm capacity. The TSO does 
not reallocate the withdrawn capacity to another user in case there is available capacity at the IP 
or capacity has been surrendered by network users. A network user having its capacity withdrawn 
retains rights and obligations until this capacity has been reallocated. 

170 The mechanism is described in “Code of Operations part H” (link). 

146 

            
       
 
 
 
 
 
Italy 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

- 
 (at IPs 
Travisio and 
Gorizia) 

- 

- 

 

 

 (at IP Passo 
Gries) 
 

- 

- 

- 

- 

Firm day ahead use-it-or-lose-it171 

- 

- 

- 

- 

- 

- 

- 

- 

The  FDA  UIOLI  applies  only  at  IPs  Travisio  and  Gorizia.  The  mechanism  is  activated  only  on  the 
days of a month, in case during the preceding month, either: 

• 

Firm capacity at the IP was not available because it was fully allocated in previous annual 
and quarterly capacity auctions, or 

•  The demanded firm capacity at the IP exceeded the available capacity. This condition is met 

if there is a premium at the relevant auction for firm capacity. 

The TSO must monitor the above conditions at the end of each monthly firm capacity auction and, 
if confirmed, must notify all network users. Once the mechanism is activated by the TSO at an IP 
entry or exit, the following restrictions apply to the network users’ renominations: 

i. 

ii. 

The  user  can  increase  its  renomination  upwards  to  a  maximum  of  90%  of  its  booked 
capacity,  or  up  to  half  of  the  non-nominated  booked  capacity  if  the  initial  nomination 
exceeded 80%. 

The  user  can  decrease  its  renomination  downwards  to  a  minimum  of  10%  of  its  booked 
capacity, or up to half of its initial nomination if this was below 20%. 

The users can renominate upward above the restrictions of point (i); however, their nomination will 
be  treated  as  interruptible.  Any  downward  renomination  below  the  restrictions  of  point  (ii)  are 
rejected  by  the  TSO.  If  capacity  is  partially  reallocated,  then  the  TSO  withdraws  the  capacity  of 
each user on a pro-rata basis. 

The above restrictions do not apply to the network users that have booked less than 10% of the 
capacity at the IP during the gas year prior to the month of the mechanism’s application. 

The  capacity  released  through  the  mechanism  is  made  available  by  the  TSO  through  the  firm 
capacity auctions for daily and within-day products.  

If the firm capacity of a network user, released through the FDA UIOLI mechanism, is reallocated 
to  another  user,  then  the  TSO  must  pay,  to  the  user  having  its  capacity  released,  an  amount 
corresponding  to  the  reserve  price  and  auction  premium  at  the  auction  that  the  capacity  was 
reallocated, while the user must pay to the TSO the network charges for the withdrawn capacity at 
the price it was initially contracted.  

171 The mechanism is described in the “SRG NETWORK CODE” (link). 

147 

            
       
 
 
 
Surrender of capacity172 

Network users can surrender their firm capacity to the TSO, provided that it has been booked for a 
minimum period of one gas-day. Bundled capacity must be surrendered only as bundled. 

The  surrendered  capacity  is  offered  and  booked  in  the  primary  market  via  the  PRISMA  booking 
platform. This capacity is allocated by the TSO only if the available capacity at the IP has been sold. 

The network users must submit applications to the TSO until a deadline that allows their inclusion 
in the subsequent auctions:  

•  Annual, quarterly, and monthly capacity surrenders: For inclusion in the respective auction, 
the capacity must be surrendered by 10:00 on the second working day before the respective 
capacity publication deadlines. 

•  Daily  capacity  surrenders:  For  inclusion  in  the  next  daily  auction,  the  capacity  must  be 

surrendered by 10:00 on the day before the gas day of surrender. 

If  the  surrendered  capacity  is  reallocated,  then  the  TSO  must  pay,  to  the  user  surrendering  its 
capacity, an amount corresponding to the reserve price and auction premium at the auction that 
the  capacity  was  reallocated,  while  the  user  must  pay  to  the  TSO  the  network  charges  for  the 
withdrawn capacity at the price it was initially contracted.  

If multiple network users surrendered their capacity for the same period, this is reallocated on a 
first-come first-served basis. 

Long-term use-it-or-lose-it173 

The LT UIOLI applies at the IPs Passo Gries, Travisio and Gorizia. At these IPs, the network users 
must make their firm capacity available for booking by third parties through the TSO, if the following 
conditions apply during a gas year: 

•  As of 1st October, the user holds firm capacity at the IP for a period exceeding one year 

under one or more transportation contracts. 

•  The  user's  average  utilization  of  its  booked  capacity  at  the  IP  is  less  than  80%  in  both 
periods from 1st October to 31st March and from 1st April to 30th September of the examined 
gas year. 

•  The user has not made the unused capacity available in the secondary market, at a price 

no higher than the reserve price, or has not surrendered this capacity to the TSO. 

•  The available capacity for booking at the IP from 1st February of the following gas year is 

fully allocated. 

The TSO monitors the above criteria after each auction. The network users can provide additional 
information to the TSO justifying why the capacity was not used. If the above criteria apply, the 
TSO: 

• 

Informs the NRA and the user of the required capacity to be made available for third-party 
booking. 

•  Submits any supporting documentation provided by the network the user. 

•  Reports any refusal by the user to trade capacity on the secondary market. 

172 The mechanism is described in the “SRG NETWORK CODE” (link). 

173 The mechanism is described in the SRG NETWORK CODE (link). 

148 

            
       
 
 
 
If the user does not justify adequately the underutilization, the TSO proceeds with withdrawing its 
capacity: 

•  At its own initiative, if the user failed to provide any supporting documentation, or 

• 

Following a decision by the NRA, if the supporting documentation by the user is insufficient 
to justify the underutilization of capacity. 

The  withdrawn  capacity  is  offered  by  the  TSO  at  the  primary  market  via  the  PRISMA  booking 
platform.  The  amount  of  capacity  withdrawn  corresponds  to  the  part  of  capacity  that  was 
underutilized  by  the  user.  The  capacity  is  made  available  as  firm  annual,  quarterly  and  monthly 
capacity at the respective auctions, with validity from 1st February of the next gas year until the 
expiration of the capacity’s duration.  

If  the  withdrawn  capacity  is  reallocated,  then  the  TSO  must  pay,  to  the  user  surrendering  its 
capacity,  an  amount  corresponding  to  the  reserve  price  at  the  auction  that  the  capacity  was 
reallocated, while the user must pay to the TSO the network charges for the withdrawn capacity at 
the price it was initially contracted.  

Management of congestion at LNG terminals174 

A UIOLI mechanism applies at LNG terminals. 

If, during a gas year, a network user does not utilize at least 90% of its capacity booked on annual 
and multiannual basis, then in the subsequent gas year it must make the underutilized part of the 
regasification  capacity  (including  unloading  slots)  available  to  the  terminal  operator,  to  be 
reallocated to third parties in the secondary market. 

At  the  end  of  each  gas  year  the  terminal  operator  assesses  whether  any  terminal  users  have 
underutilized their capacity. If so, it notifies the NRA and the user about the amount of capacity 
that  must  be  offered  in  the  secondary  market.  The  users  have  the  right  to  submit  supporting 
documentation, in order to challenge the operator’s decision.  

The user having its capacity withdrawn retains its rights and obligations for this capacity, until and 
to the extent that it is reallocated to a third party. 

Management of congestion at underground storage facilities 

The SSOs do not apply any specific measures to manage congestion. Storage capacity in Italy is  
allocated  mostly  on  an  annual  and  firm  day  ahead-term  basis.  The  operators  also  offer  unused 
capacity on a short-term interruptible basis. The SSOs must organize auctions for monthly, weekly 
and daily storage, withdrawal and injection capacity (in unbundled form), both on a continuous and 
interruptible basis. 

174 The mechanism is described in the “ARERA deliberation 660/2017/R/gas”  (link). 

149 

            
       
 
 
 
 
 
 
 
Latvia 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

 

- 

 

 

 

- 

 

 

 

- 

 

 

 

- 

 

 

Oversubscription and buy-back 175 

The oversubscription and buy-back scheme applies at the entry and exit points of the transmission 
system only in case of contractual congestion, and upon receiving a request from a network user 
to book firm capacity. In such a case, the TSO proceeds with assessing statistical data on booked 
and utilized capacity at the network point. If analysis indicates that not all technical capacity at the 
network  point  was  fully  utilized  and  considering  potential  scenarios  of  unused  capacity  for  the 
designated  period,  the  TSO  offers  additional  firm  capacity  at  that  point,  beyond  the  technical 
capacity.  In  offering  additional  capacity,  the  TSO  must  evaluate  the  associated  risks  and  the 
probability of having to buy back the additional capacity that has been sold to the market. 

Network users wishing to book additional capacity for a gas day must submit their applications to 
the TSO by 10:00 on the gas day before (or the last working day if the gas day falls on a weekend 
or  holiday).  The  TSO  must  calculate  the  available  additional  capacity  within  2  hours  and 
communicate the results to the interested network users. 

In situations where all network users intend to fully utilize their booked firm capacity at an entry or 
exit point, and the TSO is unable to meet demand for the use of the system, it must initiate the 
capacity buy-back procedure and repurchase capacity exceeding the technical limit from network 
users via the secondary market. 

The TSO notifies network users of the required buy-back quantity and the maximum price by 10:00 
UTC.  The  buy-back  price  is  capped  to  3  times  the  within-day  capacity  tariff  applicable  for  the 
particular  gas  day.  Network  users  holding  firm  capacity  products  at  that  network  point  for  the 
particular gas day may sell their capacity to the TSO by submitting an offer within 2 hours. Each 
offer must specify the volume of capacity available for buy-back and the requested price. 

The TSO may accept the users’ offers partially or in full. The TSO assesses the users’ offers on the 
basis of a lowest price priority and may buy offered capacity in full or partially. The TSO informs 
the users within 2 hours after the submission deadline. 

In  case,  following  the  capacity  buy-back  procedure,  the  TSO  is  still  unable  to  meet  all  approved 
nominations  for  firm  capacity  on  the  particular  gas  day,  it  applies  restrictions  to  firm  standard 
capacity  products.  The  shorter-term  capacity  products  (starting  with  within-day  capacity)  are 
interrupted first. If multiple firm capacity products with the same duration are affected, restrictions 
apply proportionally to the submitted nominations for the gas day. 

175 The mechanism is described in the “On the Harmonization of the Unified Rules for the Use of the Natural Gas Transmission 

System  (link). 

150 

            
       
 
 
 
Surrender of capacity176 

Network users have the right to surrender firm capacity to the TSO at an entry or exit point in case 
they  are  not  planning  to  use  it.  The  TSO  shall  accept  the  surrender  of  firm  capacity  for  daily, 
monthly, quarterly, and yearly products. Capacity can be surrendered for part or the whole period 
of the particular capacity product. Interruptible capacity cannot be surrendered. 

The user interested in surrendering its capacity must submit an application to the TSO until 08:00 
UTC  on gas day previous to the use of the system. Upon receiving a capacity surrender application, 
the  TSO  publishes  information  regarding  the  quantity  of  surrendered  capacity  and  offers  the 
surrendered capacity to the market at the particular entry or exit point together with the primary 
capacity.  The  TSO  reallocates  surrendered  capacity  at  a  network  point  only  if  all  available  firm 
capacity  has  been  allocated  and  a  user  requests  firm  capacity.  Network  users  that  surrender 
capacity must refrain from actions that hinder the reallocation of this capacity. 

Until  the  surrendered  capacity  is  successfully  reallocated,  all  rights  and  obligations  under  the 
transmission  contract  remain  with  the  original  network  user.  Once  the  surrendered  capacity  is 
reallocated, the original network user is released from the payment obligation for the corresponding 
amount, starting from the shortest duration capacity product. Correspondingly, the receiving user 
must  pay  the  applicable  capacity  product  tariff  as  set  at  the  time  of  the  original  booking  by  the 
surrendering user, starting from the shortest duration capacity product. 

If multiple network users submit surrender applications at a network point for the same gas day, 
the TSO reallocates capacity on a first-come first-served basis. 

Long-term use-it-or-lose-it177 

The TSO has the right to withdraw yearly booked capacity from a network user at an entry or exit 
point, if at least one of the following conditions is met at the particular network point: 

•  The network user utilizes less than 80% of its contracted capacity on average during the 
period 1st April – 30th September and 1st October – 31st March, while having booked capacity 
with  a  duration  exceeding  one  year  and  fails  to  provide  a  valid  justification  for  the 
underutilization to the TSO. 

•  The  network  user  systematically  nominates  more  than  80%  of  its  booked  capacity  but 

subsequently renominates downwards below 80%. 

If the TSO identifies cases of underutilization based on the above criteria, it must notify the network 
user, which then has 10 calendar days to either sell the underutilized capacity on the secondary 
market or surrender the capacity to the TSO. If the network user fails to take appropriate action 
within the given timeframe, it loses the unused portion of the booked capacity. 

Until  the  TSO  successfully  reallocates  the  capacity,  the  network  user  retains  all  its  rights  and 
obligations under the transmission contract. 

Management of congestion at underground storage facilities 

The SSO does not apply specific measures to manage contractual congestion at their underground 
storage facility. 

176 The mechanism is described in the “On the Harmonization of the Unified Rules for the Use of the Natural Gas Transmission 

System  (link). 

177 The mechanism is described in the “On the Harmonization of the Unified Rules for the Use of the Natural Gas Transmission 

System  (link). 

151 

            
       
 
 
 
 
Lithuania 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

- 

- 

- 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 178 

The  oversubscription  and  buy-back  scheme  applies  at  IPs  with  Member  States  only  in  case  of 
contractual congestion, and upon receiving a request from a network user to book firm capacity. In 
such a case, the TSO proceeds with assessing statistical data on booked and utilized capacity at the 
IP. If analysis indicates that not all technical capacity at the IP was fully utilized and considering 
potential  scenarios  of  unused  capacity  for  the  designated  period,  the  TSO  offers  additional  firm 
capacity at that point, beyond the technical capacity. In offering additional capacity, the TSO must 
evaluate the associated risks and the probability of having to buy back the additional capacity that 
has been sold to the market. 

Network users wishing to book additional capacity for a gas day must submit their applications to 
the TSO by 10:00 on the gas day before (or the last working day if the gas day falls on a weekend 
or  holiday).  The  TSO  must  calculate  the  available  additional  capacity  within  2  hours  and 
communicate the results to the interested network users. 

In situations where all network users intend to fully utilize their booked firm capacity at an IP, and 
the TSO is unable to meet demand for the use of the system, it must initiate the capacity buy-back 
procedure  and  repurchase  capacity  exceeding  the  technical  limit  from  network  users  via  the 
secondary market. 

The TSO notifies network users of the required buy-back quantity and the maximum price by 12:00. 
The buy-back price is capped at 3 times the within-day capacity tariff applicable for the particular 
gas day. Network users holding firm capacity products at that network point for the particular gas 
day may sell their capacity to the TSO by submitting an offer within 2 hours. Each offer must specify 
the volume of capacity available for buy-back and the requested price. 

The TSO may accept the users’ offers partially or in full. The TSO assesses the users’ offers on the 
basis of a low price priority and may buy offered capacity in full or partially. The TSO informs the 
users within 2 hours after the submission deadline. 

In  case,  following  the  capacity  buy-back  procedure,  the  TSO  is  still  unable  to  meet  all  approved 
nominations  for  firm  capacity  on  the  particular  gas  day,  it  applies  restrictions  to  firm  standard 
capacity  products.  The  shorter-term  capacity  products  (starting  with  within-day  capacity)  are 
interrupted first. If multiple firm capacity products with the same duration are affected, restrictions 
apply proportionally to the submitted nominations for the gas day. 

178 The mechanism is described in the “AB Amber Grid rules for Access to the Natural Gas Transmission System” (link). 

152 

            
       
 
 
 
Surrender of capacity179 

Network users have the right to surrender to the TSO capacity acquired on the primary market at 
an IP with an EU Member State or at the interface with the LNG terminal, provided that the capacity 
product surrendered has a validity term of at least one day. 

If a network user surrenders its capacity using the TSO’s electronic platform, then the TSO must 
publish information about the surrender in real time. In the user applies for the capacity surrender 
in writing to the TSO, then:  

• 

• 

If there is already contractual congestion at the relevant entry or exit point, the TSO  will 
post  information  about  the  surrendered  capacity  (including  its  volume  and  the  specific 
entry/exit point) on its electronic platform within 2 working days. 

If there is no contractual congestion at the network point at the time of the surrender, the 
TSO will post the information on its electronic platform within 1 working day after contractual 
congestion occurs. 

The  TSO  will  reallocate  surrendered  capacity  when  there  are  network  users  willing  to  acquire 
capacity at the specific entry or exit point. Until the surrendered capacity is reallocated by the TSO, 
the original network user retains all rights and obligations associated with the surrendered capacity. 

If multiple network users submit surrender applications at a network point for the same gas day, 
the  TSO  reallocates  capacity  on  a  first-come  first-served  basis.  If  the  demand  for  surrendered 
capacity exceeds the volume of surrendered capacity available, the TSO will allocate the capacity 
proportionally to the requested capacity. 

Long-term use-it-or-lose-it180 

The TSO reserves the right to withdraw, either partially or entirely, underutilized capacity from a 
network user at an IP with an EU Member State or at the interface with the LNG terminal, provided 
that: 

•  The network user has not sold or offered the unused capacity under acceptable terms in the 

secondary market or has not surrendered it to the TSO, and 

•  Other network users have requested firm capacity at the same entry/exit point. 

A network point is considered underutilized if the following conditions are met: 

•  The TSO cannot fully or partially satisfy the requests of network users at the network point 

for capacity of one year or longer. 

•  The TSO determines that, at the network point, other network users utilized less than 80% 
of their booked capacity during the periods from 1st April to 30th September and 1st October 
to  31st  March,  and  these  users  have  not  made  the  unused  capacity  available  in  the 
secondary market. 

The TSO notifies network users with underutilized capacity, which have 5 working days to offer this 
capacity  in  the  secondary  market.  Following  this  notification,  if  network  users  seeking  capacity 
cannot acquire it from the secondary market within 10 working days, the TSO requests from the 
users with underutilized capacity to justify, within 5 working days, their actual needs for using the 
network point. 

179 The mechanism is described in the “AB Amber Grid rules for Access to the Natural Gas Transmission System” (link). 

180 The mechanism is described in the “AB Amber Grid rules for Access to the Natural Gas Transmission System” (link). 

153 

            
       
 
 
 
If  the  network  users  cannot  justify  the  underutilization,  the  TSO  proceeds  with  withdrawing  the 
unused capacity, up to the amount of capacity requested by other users. The withdrawn capacity is 
reallocated to the network users that have requested capacity at the specific network point. The 
user acquiring the capacity must pay the network charges proportionately to the remaining period 
of the capacity duration. If more than one user have their capacity withdrawn at the network point, 
then the capacity is withdrawn proportionately to the amount of unused capacity of each network 
user. 

The  original  network  user  retains  all  rights  and  obligations  for  the  unused  capacity  until  it  is 
reallocated by the TSO. The original network user is not refunded for having its capacity reallocated 
to another user. 

Management of congestion at LNG terminals181 

A mechanism addressing underutilization of capacity, and a UIOLI mechanism apply at the Klaipeda 
LNG terminal. 

In the event of terminal congestion, if a terminal user fails to utilize 20% or more of their booked 
capacity over any six-month period, the terminal operator has the right to unilaterally reduce the 
user’s capacity for the current and all subsequent gas years by the amount of the unused capacity. 
The withdrawn capacities are made available for allocation in the primary market. 

This condition does not apply to a terminal user having booked more than half of the total terminal 
capacity. However, if such a terminal user fails to use 10% or more of their allocated capacities 
over  any  three-month  period,  the  operator  may  reduce  their  capacities  for  the  current  and/or 
subsequent gas years. This reduction is subject to a review of evidence provided by the terminal 
user  demonstrating  their  intent  to  utilize  the  allocated  capacity  in  the  future  if  such  evidence  is 
requested by the operator. 

A UIOLI mechanism also applies for capacities that the terminal users do not intend to use. The 
terminal operator verifies with the users the amount of booked capacity that they intend to use. In 
case capacity is not to be used by the users holding the capacity rights, the operator reduces the 
capacity of these users and makes the unused capacity available in the primary market. 

Terminal users are relieved of payment obligations for capacities reallocated to other terminal users. 

181 The mechanism is described in the “Regulations for use of the Liquefied Natural Gas Terminal” (link). 

154 

            
       
 
 
 
 
 
 
Netherlands 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 182 

The  TSO  can  apply  an  OS+BB  scheme  to  offer  additional  firm  capacity,  exceeding  the  technical 
capacity at its IPs with other EU States and also non-EU countries. 

The methodology for calculating the additional firm capacity to be offered through oversubscription 
is differentiated in terms of time period: day, month, quarter and year. For each time period the 
TSO  determines  the  additional  capacity  on  the  basis  of  statistical  scenarios  of  the  anticipated 
quantity  of  unused  physical  entry  or  exit  capacity  and  the  estimated  risk  of  excessive  buyback 
obligations for the respective period (day, month, quarter, year). The additional capacity is offered 
by the TSO together with the available capacity in the respective firm capacity auction. 

If the nominations for firm capacity exceed the technical capacity at an IP, and there is a risk for 
the  integrity  of  the  system,  the  TSO  must  activate  a  buyback  auction  at  the  specific  IP.  For  the 
activation of the procedure the TSO sends a notification which is sent to network users 3 hours prior 
to the hour in which the bottleneck is expected to occur. The notification must define the hourly 
quantity that the TSO is looking to buy back and the hours for which capacity will be bought. The 
users that want to offer their capacity must place bids in 30 minutes. The auction is carried out 
using a uniform-price algorithm. 

Surrender of capacity183 

A network user holding firm capacity at an IP has the right to surrender it to the TSO. Only yearly, 
quarterly and monthly capacity can be surrendered, and this capacity must remain constant for the 
duration of the surrender period.  

The surrendered capacity is sold by the TSO in the primary capacity market, after the available firm 
capacity at the IP has been allocated. The user must return its capacity at least 5 working days 
prior  to  the  respective  yearly,  quarterly  or  monthly  auctions.  The  network  user  cannot  sell  its 
surrendered capacity in the secondary market until the respective auction has ended. 

After  the  surrendered  capacity  has  been  reallocated  to  another  user,  the  surrendering  user  is 
released  from  its  obligation  to  pay  network  charges  for  the  part  of  capacity  that  has  been 
reallocated. 

If  more  than  one  network  user  surrender  capacity  for  the  same  auction,  the  TSO  allocates  this 
capacity on a first-come first-served basis.  

182 The mechanism is described in the “Gasunie, Transmission Code Gas 3-6-2020” (link). 

183 The mechanism is described in the “Gasunie, Transmission Code Gas 3-6-2020” (link). 

155 

            
       
 
 
 
Long-term use-it-or-lose-it184 

The  regulators  of  Belgium,  the  Netherlands  and  the  UK  have  agreed  on  a  vision  for  the 
implementation of the LT UIOLI mechanism in line with the CMP Guidelines. This vision defines  the 
key elements of the mechanism, including the monitoring procedure, definition of key terms, and 
the criteria for activation. 

The LT UIOLI mechanism only applies to multiannual firm capacity contracts, or a series of one-
year contracts of at least two consecutive years. The mechanism is activated at an IP, in case there 
has  been  unmet  demand  for  firm  capacity  by  network  users  and  one  or  more  users  have  been 
systematically underutilizing their booked capacity. 

Capacity is considered as systematically underutilized if: 

• 

• 

The network user uses on average less than 80% of its booked capacity for both periods 
between 1st April to 30th September and 1st October to 31st March (monitoring periods). 

The network user cannot provide proper justification for underutilizing its capacity. 

 The capacity is not considered as systematically underutilized in case the network user offered this 
capacity at on the PRISMA secondary platform for at least three consecutive months ahead (or a 
combination of the two), for a price up to the reserve price in the latest yearly auction within the 
respective monitoring period.  

If all criteria are met, the relevant user will be required to justify its underutilisation to the relevant 
NRA. Where the NRA considers that no proper justification has been provided, the TSO is required 
by the NRA to withdraw up to 80% of the user’s contracted capacity, for an effective duration of 2 
gas years.  

The TSO offers the withdrawn capacity in the first possible yearly and quarterly auctions. Capacity 
not sold in the auction of the year-ahead product is rolled on to the auction of quarterly products. 
If the released capacity is not sold entirely, the user keeps its rights and obligations for the capacity 
that has not been sold. 

Management of congestion at LNG terminals185 

A use-it-or-lose-it mechanism applies at the Gate LNG terminal, to manage contractual congestion. 
The following principles apply: 

•  Unused capacity must be offered in the secondary market. 

•  A  terminal  user  with  booked  capacity  at  the  facility  must  notify  the  operator  at  least  30 
days in advance if it does not intend to use the booked berthing slot and offer the unused 
slot for sale. 

• 

• 

If the terminal used does not offer its unused capacity in the secondary market, then the 
operator must activate the UIOLI mechanism. 

The terminal operator must offer the unused capacity in the secondary market, ensuring 
that it is available at least 30 days before the planned start of regasification.    

Management of congestion at underground storage facilities 

The SSOs do not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

184 The mechanism is described in ACM 2015 Visiedocument Long Term Use-it-or-lose-it (LT UIOLI) (link). 

185 The mechanism is described in the Commission Decision (17/7/2023) on the exemption of Gate Terminal B.V. (link). 

156 

            
       
 
 
 
Use of congestion revenues 

The congestion revenues can be used to decrease tariffs or to invest in new infrastructure to lift 
any  potential  bottlenecks.  Since  the  network  in  the  Netherlands  is  well  developed,  usually  the 
revenues are used to decrease the network charges for the transmission system.  

157 

            
       
 
 
 
 
 
Poland 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-
UIOLI186 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

 (congested 
IPs) 

 

 

 

 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 187 

The TSO can offer additional firm capacity on a daily basis, beyond the technical capacity of the IP, 
after considering the technical conditions, expected offtakes from the system and capacity in the 
adjacent  transmission  systems.  In  such  a  case,  the TSO  must  publish  the  additional  capacity  by 
12:00 of the previous gas day.  

In  the  event  that  there  is  congestion  at  an  IP,  as  a  result  of  the  oversubscribed  capacity  made 
available, the buy-back mechanism is activated. The TSO must notify network users holding firm 
capacity at the IP, that they can offer their capacity at a buy-back auction. The notification must be 
announced by the TSO at least 30 minutes before the start of the auction.  

The  buy-back  auction  takes  place  at  the  auction  platform  indicated  by  the  TSO188,  with  a  single 
round lasting 30 minutes. A uniform-price auction algorithm is applied, ranking the bids based on 
the  unit  price  offered  by  each  network  user.  The  buy-back  price  cannot  exceed  a  multiple  of  10 
times the tariff for the daily firm capacity product at the IP on the particular gas day. 

In case the auction is not sufficient to eliminate the congestion, the TSO reduces the allocated firm 
capacity  starting  from  the  product  with  the  shortest duration up  to  the  product  with  the longest 
duration. In case several users hold products with the same duration, the reduction is performed 
proportionately  to  the  confirmed  quantities  of  each  user.  Network  users  having  their  allocated 
capacity  reduced  are  provided  with  a  discount  in  the  fixed  fee  for  the  transmission  services 
proportionally to the extent of the actual reduction of the contracted capacity and the duration (in 
hours) of such interruptions or disruptions.  

Firm day ahead use-it-or-lose-it189 

The FDA UIOLI mechanism applies at an IP in case it has been identified as congested in ACER’s 
Congestion  Report,  unless  the  NRA  decides  that  there  is  high  probability  that  the  congestion  is 
unlikely to reoccur again in the next 3 years.  

186 An FDA UIOLI mechanism is foreseen in the regulation. In practice, however the NRA has decided not to activate it at the 
IPs identified in ACER’s Congestion Report as congestion, because it expected, with a high degree of probability, that the 
situation leading to label the IPs as congested would not recur within the next three years. 

187 The mechanism is described in the Gaz-System “Transmission Network Code” (link). 

188 The TSO in Poland offers capacity under different auction platforms at different IPs. 

189 The mechanism is described in the Gaz-System “Transmission Network Code” (link). 

158 

            
       
 
 
 
Activation of the FDA UIOLI mechanism at an IP results in the following renomination restrictions 
for the network users: 

• 

• 

• 

The network user can renominate up to 90% and down to 10% of its booked capacity at 
the IP. 

If the nomination exceeds 80% of the booked capacity, half of the non-nominated volume 
may be renominated upwards. When it comes to the remaining allocated capacity of the 
given  Shipper,  the  renomination  is  treated  as  complex  renomination  for  interruptible 
capacity  

If the nomination does not exceed 20% of the contracted capacity, half of the nominated 
volume may be renominated downwards. 

The renomination restrictions of the FDA UIOLI mechanism do not apply to network users that have 
booked less than 10% of the average technical capacity of the IP in the gas year preceding the year 
of renomination. 

Surrender of capacity190 

Network users holding firm capacity at IPs have the right to surrender it to the TSO. The TSO shall 
not offer capacity (contractual capacity) surrendered by the Network User as part of products for a 
period of one gas day.  Bundled capacity must be surrendered to both TSOs. The TSO offers the 
surrendered capacity in the primary market. This capacity is allocated only after all available firm 
capacity at the IP has been sold.  

The network user surrendering its capacity retains its rights and obligations under the transmission 
contract until the capacity has been reallocated by the TSO to another user. In any case, the user 
that surrendered the capacity must pay to the TSO the auction premium (if any) that occurred when 
it initially booked the capacity being surrendered. 

If multiple network users surrender capacity on the same day, the capacity is reallocated by the 
TSO on a first-come first-served basis. 

Long-term use-it-or-lose-it191 

The TSO must monitor the use of the firm capacity booked by the network users at the IPs. The 
TSO  must  notify  the  NRA  in  case  there  is  request  for  capacity  at  an  IP  and  a  network  user  is 
systematically underutilizing its firm capacity booked at the IP with duration longer than 1 gas year. 

Firm capacity is considered as systematically underutilized if the user: 

•  Uses its capacity, booked with duration over 1 gas year, on an annual basis less than 80% 
of its booked capacity both for the period from 1st April to 30th September and 1st October 
to 31st March. 

•  Has failed to sell or release its capacity in the secondary market at reasonable terms or to 

surrender it to the TSO. 

•  Has failed to justify the underutilization of the capacity. 

After the NRA has been notified by the TSO, it proceeds with a decision to withdraw, in part or in 
full, the capacity of the affected network user. 

190 The mechanism is described in the Gaz-System “Transmission Network Code” (link). 

191 The mechanism is described in the Gaz-System “Transmission Network Code” (link). 

159 

            
       
 
 
 
Management of congestion at LNG terminals192 

A UIOLI mechanism applies at the Polish LNG terminal. 

The terminal operator must monitor the use of the contracted regasification capacity.  

If there is no available capacity to serve a new request for regasification capacity, and at the same 
time there is booked but unused capacity at the terminal, then the operator must request from the 
terminal user underutilizing its capacity to provide a justification within 15 days. If the user fails to 
justify why the capacity is not used, the terminal operator, after consultation with the NRA, requires 
the user to sell its unutilized capacity in the secondary market. 

If a terminal user, within the period of 1 gas year, uses less than 50% of the 95% of their booked 
regasification capacity, the operator must request from the terminal user underutilizing its capacity 
to provide a justification within 15 days. If the user fails to justify why the capacity is not used, the 
terminal operator, after consultation with the NRA, can unilaterally withdraw the user’s capacity for 
the current year, up to the underutilized amount, and make this capacity available for other users. 

Until  the  withdrawn  capacity  is  reallocated  to  another  terminal  user,  the  initial  user  can  use  the 
withdrawn capacity. 

Management of congestion at underground storage facilities193 

The SSO applies a surrender procedure and a UIOLI mechanism to manage contractual congestion. 

A  storage  user  has  the  right  to  submit  an  application  to  storage  operator  for  a  reduction  of  the 
storage  capacity  allocated  under  a  long-term  storage  contract,  when  the  storage  user  does  not 
intend to use this storage capacity (excess storage capacity). In its application, the user specifies 
the amount of capacity it surrenders to the SSO. In such a case, the SSO offers the surrendered 
capacity as available capacity at the storage facility. The original storage user retains its rights and 
obligations regarding the surrendered capacity until this capacity has been reallocated to another 
user.  

If, after the end of a storage year, a storage user with capacity booked under a long-term storage 
contract, has not utilized at least 80% of its contracted capacity for at least one storage year (or 6 
consecutive  months  in  the  case  of  UGS  Kawerna),  then  the  SSO  must  request  from  this  user  a 
justification  for  not  using  the  capacity,  within  15  working  days.  If  the  user  fails  to  provide  a 
justification, the SSO obliges the storage user to surrender its excess storage capacity, within 10 
working  days.  If  the  user  does  not  submit  such  an  application,  the  SSO  reduces  the  capacity 
unilaterally. 

Use of congestion revenues 

The NRA has decided to use the congestion revenues from the sale of capacity to reduce the 
tariffs for the subsequent tariff periods. 

192 The mechanism is described in the “LNG Terminal Code for Liquefied Natural Gas Regasification Facility in Świnoujście” 

(link). 

193 The mechanism is described in Gas Storage Poland, Storage Code (link). 

160 

            
       
 
 
 
 
 
Portugal 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 194 

An OS+BB scheme applies at the VIP Iberico, in accordance with a joint decision of the TSO with 
the adjacent Spanish TSO. The joint decision determines the main principles for offering additional 
firm capacity at the VIP beyond the technical capacity at the network point, the methodology and 
procedure for calculating the additional capacity, the buy-back procedure and the pricing for the 
capacity at the VIP. The mechanism applies only to bundled capacity at the VIP. 

The TSO may offer additional firm capacity if there is contractual congestion and the nominations 
at the VIP are below 100%. The additional firm capacity is calculated through a probabilistic model 
that  takes  into  account,  for  a  given  day,  the  historic  utilization  of  capacity  and  expected  gas 
demand, as well as the risks for possible buy-back of the additional capacity. If the conditions for 
offering additional capacity are met for a gas day, the TSO announces the total quantity, which is 
offered as a daily standard firm capacity product, together with the available capacity (without any 
distinctions), at the respective capacity auction. 

If the total nominations at the VIP on a gas day exceed its technical capacity, and technical and 
market measures (interruption of interruptible capacities, management of the operating balancing 
account) are not sufficient to meet demand for capacity, then the TSO activates, together with the 
adjacent Spanish TSO, the buy-back procedure. The network users that have booked capacity at 
the VIP on the gas day may enter the buy-back auction, conducted at the secondary market of the  
PRISMA booking platform, and sell their capacity back to the TSOs. The TSOs must announce the 
amount of capacity that needs to be bought back, the maximum price at each side of the VIP, and 
the list of network users that can take part in the auction. At the Portuguese side, the price at which 
capacity is offered by the users cannot exceed the daily capacity tariff for the gas day, multiplied 
by a factor of 1.2.  

The offers from the network users are ranked according to the price, with the lowest price ranking 
first. In case the capacity bought back from the users is not sufficient to cover all capacity needs at 
the  VIP,  the  TSOs  reduce  the  users’  capacity  proportionately  to  their  submitted  nominations.  In 
such a case, the TSOs must compensate the network users for the reduced capacity, using the daily 
reference price applied on that gas day. 

194 The mechanism is described in the “Manual de Procedimentos do Acesso às Infraestruturas (MPAI)” (link) and the Joint 

Decision of Enagás, REN and TIGF (2016) on an oversubscription and buy-back scheme (link). 

161 

            
       
 
 
 
 
 
Surrender of capacity195 

The network users have the right to surrender their firm capacity at the VIP, with duration of over 
1 day. Both bundled and unbundled capacity can be surrendered, without however changing the 
status of the capacity from bundled to unbundled and vice versa. After surrendering capacity, the 
network users may not offer the same capacity in the secondary market. 

The user can surrender part or whole of its booked capacity at the VIP. The surrendered capacity is 
offered  by  the  TSO  in the  primary  capacity  market as  a  standardized  firm  product  with  a  period 
shorter than the one being surrendered: 

• 

Yearly capacity is offered as quarterly, monthly and daily products. 

•  Quarterly capacity is offered as monthly and daily products. 

•  Monthly capacity is offered as daily products. 

To surrender capacity, the users must meet the following deadlines: 

•  Annual products can be sold as quarterly products if they are surrendered up to 15 days 

prior to the auction for the quarterly capacity. 

•  Annual and quarterly products can be sold as monthly products if they are surrendered up 

to 10 days prior to the auction for the monthly capacity. 

•  Annual,  quarterly  and  monthly  products  can  be  sold  as  daily  products  if  they  are 

surrendered up to 3 days prior to the auction for the daily capacity. 

The surrendered capacity can be reallocated to other users by the TSO only after the available firm 
capacity  at  the  VIP  has  been  booked.  If  the  surrendered  capacity  has  not  been  allocated  in  an 
auction, the network user may either retrieve it or leave it to be offered in the next auction. 

The network user surrendering capacity must pay all relevant network charges until the capacity is 
reallocated to another user. After reallocation, the initial user retains the obligation to pay to the 
TSO the difference between the original price for booking the surrendered capacity and the resale 
price at the corresponding auction. If the resale price exceeds the original one, the network user 
surrendering the capacity is not entitled of any compensation. 

In case several network users surrender capacities on the same day, these are reallocated to other 
users on a first-come first-served basis. 

Long-term use-it-or-lose-it196 

The  TSO  has  agreed  with  the  adjacent  Spanish  TSO  on  a  joint  implementation  of  the  LT  UIOLI 
mechanism  at  VIP  Iberico.  This  includes  a  common  approach  on  the  key  elements  of  the 
mechanism, such as the  monitoring requirements for the use of capacity, criteria for systematically 
underutilized capacity, the withdrawal of capacity and its offering to the primary market. 

Each year, in April, the TSO must calculate the use of capacity by the network users at the VIP and 
inform the NRA. For this purpose, the TSO determines the level of utilization of capacity for each 
user for each of the following periods (monitoring periods): 

• 

• 

From 1st April to 30th September of the preceding year. 

From 1st October of the preceding year to 31st May of the current year. 

195 The mechanism is described in the “Manual de Procedimentos do Acesso às Infraestruturas (MPAI)” (link). 

196 The mechanism is described in the “Manual de Procedimentos do Acesso às Infraestruturas (MPAI)” (link). 

162 

            
       
 
 
 
The TSO must activate the use-it-or-lose-it mechanism in case it identifies cases of network users 
holding long-term capacity rights, with duration of one or more years subsequent to the current 
gas year, which underutilize their booked capacity. Capacity is considered as being underutilized in 
case the following conditions apply: 

•  Use of booked capacity is on average during both monitoring periods below 80%. 

• 

In both periods there were at least 60 days at which the user nominated above 80% of its 
booked capacity and then renominated half or less than its initial nomination.  

Capacity is not considered as being underutilized if the network user has proven that it offered the 
capacity at the secondary market under reasonable conditions. Offering of capacity at the secondary 
market is considered reasonable if the price at which the capacity was made available was equal to 
or lower than the highest between the auction reserve price at the time of the offer, the price at 
which the capacity was booked, and the price of capacity at the last auction of the same product. 

If the TSO identifies a case of underutilization, it notifies the affected network user. If the latter 
justifies  why  the  booked  capacity  was  not  used  or  proves  that  the  capacity  was  offered  at  the 
secondary  market  under  reasonable  conditions,  then  the  particular  case  is  not  considered  as 
underutilization.    

By the end of May, the TSO must, in coordination with the adjacent Spanish TSO, inform the network 
users underutilizing their capacity. The affected users may submit a substantiated objection to the 
TSO,  up  to  5  working  days  after  receipt  of  the  notification.  Following  the  TSO’s  final  decision,  it 
withdraws, for the subsequent gas year, the capacity of each network user that was underutilized 
during each monitoring period. The withdrawn capacity as offered in the primary market as yearly, 
quarterly and monthly standard firm products, until it has been fully reallocated. The network user 
having its capacity withdrawn may not offer this capacity in the secondary market.  

The TSO charges the network user for the difference, if positive, between the original price at which 
the withdrawn capacity was booked and the price at which it was reallocated. 

Management of congestion at LNG terminals 

Any  congestion  at  the  LNG  terminal  is  managed  using  market  measures,  such  as  the  terminal 
operator offering interruptible capacity and the users selling any unused capacity at the secondary 
market.  

Management of congestion at underground storage facilities 

The SSO does not apply specific measures to manage contractual congestion at their underground 
storage facility.  

Use of congestion revenues 

Any  revenues  collected  by  the  TSO  due  to  auction  premia  when  allocating  capacity  are  used  to 
decrease network charges for the users.  

In case there are revenues from selling additional capacity at VIP Iberico, 90% of these are used 
to decrease the tariffs and the remaining 10% is distributed to the TSO. 

163 

            
       
 
 
 
 
Romania 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

- 

- 

 

 

- 

- 

 

 

- 

- 

 

 

- 

- 

 

 

- 

- 

 

 

Surrender of capacity197 

A network user holding firm capacity products with a duration equal to or longer than one gas month 
has the option to surrender its contracted capacity, either partially or in full. Firm bundled capacity 
may only be returned to the TSO as firm bundled capacity. 

Once an application for capacity surrender is submitted, the network user is prohibited from trading 
the  capacity  in  question  on  the  secondary  capacity  market.  However,  the  network  user  may 
withdraw the application if the surrendered capacity has not been allocated to another user. 

The TSO offers the surrendered capacity in the primary capacity market on behalf of the network 
user  until  12:00  p.m.  on  the  gas  day  before  the  validity  of  the  product.  The  capacity  products 
subject  to  surrender  are  clearly  tagged  as  "return",  to  distinguish  them  from  other  capacity 
offerings. In case the capacity remains unsold by this deadline, the network user may offer it on 
the secondary capacity market. 

The surrendered capacity can be reallocated to other users only after the available firm capacity 
offered by the TSO at the particular network point has been booked. The tariff applied to the network 
user buying the surrendered capacity is the same as the capacity at which the capacity was booked 
by the user surrendering it. Until the returned capacity, or a portion of it, is successfully allocated 
to  a  beneficiary  network  user,  the  initiating  network  user  retains  all  contractual  rights  and 
obligations associated with the returned capacity. 

If multiple network users submit applications to return capacity at the same entry and/or exit points, 
the requests are processed on a "first come, first served" basis. 

Long-term use-it-or-lose-it198 

The  TSO  monitors  the  utilization  of  contracted  capacity  with  a  duration  exceeding  one  year  or 
recurring  quarterly  contracts  spanning  at  least  two  years.  A  comprehensive  monitoring  report  is 
prepared and submitted to the NRA by October 1 of each gas year to facilitate the evaluation of 
capacity utilization. 

In the event of contractual congestion, the NRA may request the TSO to withdraw entry and/or exit 
capacity booked by a network user for one or more gas years, provided the capacity is determined 
to be underutilized. Contracted capacity is considered underutilized under the following conditions: 

197 The mechanism is described in the “Network Code of the National Gas Transmission System” (link). 

198 The mechanism is described in the “Network Code of the National Gas Transmission System” (link). 

164 

            
       
 
 
 
• 

• 

The network user uses, on average, less than 80% of its booked capacity during both the 
periods  of  1st  April  to  30th  September  and  1st  October  to 31st  March,  without providing a 
reliable justification for the low utilization. 

The  network  user  systematically  nominates  nearly  100%  of  its  booked  capacity  and 
subsequently renominates downwards. 

The maximum capacity eligible for withdrawal is calculated as the difference between the capacity 
booked by the network user and the highest level of capacity utilized by the network user during 
the relevant monitoring period. In determining this maximum withdrawal level, the TSO must take 
into consideration any transfers of capacity at the secondary market, surrender of capacity to the 
TSO or withdrawals of booked capacity made by the network user during the monitoring period. 

Management of congestion at underground storage facilities 

The SSOs do not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

165 

            
       
 
 
 
 
 
Slovakia 

Overview of CMP Guidelines application 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back 199 

The TSO may offer at IPs with Member States additional firm capacity, in addition to the technical 
capacity at the relevant direction of the IP. The amount and duration of the additional capacity is 
determined by the TSO based on statistical scenarios, which forecast the physical unused capacity 
at the relevant entry/exit point, while taking into account the risk of a potential need for the TSO 
to buy back the additional capacity. The additional capacity is offered by the TSO together with the 
available  firm  capacity,  before  surrendered  capacity  and  capacity  withdrawn  through  the  UIOLI 
mechanism are allocated. The tariffs for firm capacity apply to the additional capacity. 

In  case  of  physical  congestion  at  an  IP  due  to  the  oversubscription  of  firm  capacity,  the  TSO 
proceeds  with  interrupting  the  interruptible  capacity.  If  the  congestion  is  not  resolved,  the  TSO 
activates  a  market-based  mechanism  to  buy  back  additional  capacity  from  the  users  (buy-back 
procedure). When the buy-back procedure is activated by the TSO, the users may offer their firm 
capacity  at  the  IP,  up  to  their  nomination.  The  TSO  buys  back  capacity  following  a  lowest  price 
merit  order.  The  price  at  which  capacity  is  offered  by  the  users  is  capped  to  the  initial  price  of 
capacity for the particular user.  

In the event that the TSO is not able to buy back sufficient capacity to lift the congestion, capacity 
allocated to all users at the IP is reduced proportionately to their nominations. The capacity charges 
at  the  IP  for  the  network  users  (including  any  auction  premia)  having  their  capacity  reduced  is 
decreased on a pro-rata basis. 

Surrender of capacity200 

Network users can surrender their contracted firm capacity to the TSO, with duration longer than 1 
day.   Surrendered capacity is allocated only after all remaining firm available capacity, including 
any  additional  capacity,  has  been  allocated  by  the  TSO,  but  before  the  allocation  of  capacity 
withdrawn through the UIOLI mechanism.  

Users  surrender  their  capacity  through  the  electronic  platform  of  the  TSO.  The  TSO  must  not 
unreasonably reject a request of a user to surrender capacity, while users are free to withdraw their 
requests  until  the  moment  that  their  surrendered  capacity  is  offered  for  sale  at  a  firm  capacity 
auction.  

The original user retains the rights and obligations under the contract until the surrendered capacity 
or a part thereof, is reallocated to another user.  

199 The mechanism is described in the “Operational Order” of eustream  (link). 

200 The mechanism is described in the “Operational Order” of eustream  (link). 

166 

            
       
 
 
 
In case several network users are requesting to surrender their capacities, the reallocation is carried 
out on a first-come first-served basis. 

Long-term use-it-or-lose-it201 

The  TSO  must  monitor  the  utilization  of  booked  firm  capacity  at  an  IP.  Contracted  firm  capacity 
with  an  effective  contract  duration  of  more  than  one  year  is  considered  to  be  systematically 
underutilized if a network user uses less than 80% on average of its contracted capacity both from 
1st April until 30th September and from 1st October until 31st March.  

If an IP is systematically underutilized by a network user, and another user requests firm capacity 
that is not available through available capacity at the IP, oversubscription or surrendered capacity 
for the requested quantity and duration, the TSO asks the network user with underutilized capacity 
to provide justification for not using its capacity.  

If no proper justification is provided by the user, the TSO shall request from the NRA for approval 
for withdrawing the user’s capacity. The withdrawn capacity cannot exceed the requirements of the 
market. If the NRA approves the TSO’s request, the latter offers the withdrawn capacity to other 
network  users.  The  withdrawn  capacity  is  sold  by  the  TSO  only  after  all  available  firm  capacity 
(including additional capacity) and surrendered capacity has been allocated. 

The original user retains the rights and obligations under the contract until the surrendered capacity 
or a part thereof, is reallocated to another user.  

Management of congestion at underground storage facilities 

The SSOs do not apply specific measures to manage contractual congestion at their underground 
storage facilities.  

201 The mechanism is described in the “Operational Order” of eustream (link). 

167 

            
       
 
 
 
 
 
 
 
Slovenia 

Overview of CMP Guidelines application 

CMP 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

OS+BB202 

 

FDA-UIOLI   (congested 

Surrender 

LT-UIOLI 

IPs) 
 

 

- 

Oversubscription and buy-back 203 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

The TSO shall offer additional daily firm capacities at IPs, beyond the technical capacity of the IP, 
for particular days of the year, if statistical data indicates that the following conditions are met: 

1.  The IP has been booked on the relevant day during the past 5 years. 

2.  Transmission contracts for interruptible capacities have been concluded at the IP every year 
over the last 3 years, under which transmission occurred without interruption by the TSO. 

3.  At least 10% of the technical capacity at the IP has remained unused every year for the 

past 5 years. 

When determining additional capacities under the oversubscription, the TSO shall also consider any 
additional  capacities  made  available  through  other  congestion  management  measures.  The  TSO 
offers the additional capacity in the primary market; however, this capacity can be allocated only 
after the available capacity at the IP and any surrendered or withdrawn capacity has been allocated. 
The tariff for primary firm capacity applies to the additional capacity offered by the TSO. 

If  the  TSO  determines,  based  on  nominations  or  other  appropriate  methods,  that  network  users 
intend to utilize all their booked firm capacities at an IP on a specific day or over a longer period, 
exceeding the technical capacity of that point, then the TSO must activate the buy-back procedure. 
The TSO notifies all affected network users that hold firm capacity at the IP and invites them to 
submit bids for the selling their capacity. 

The network users interested in selling their capacity must submit, until the deadline specified by 
the TSO, their bid including the amount of firm capacity they are offering and the unit price. After 
the  deadline,  the  TSO  will  select  the  bids  starting  from  the  lowest  price.  In  the  event  of  users 
offering the same unit bid prices, priority will be given based on the order in which the bids are 
received. 

If  the  TSO  purchases  the  offered  transmission  capacity  from  a  network  user,  the  corresponding 
contractual  obligation  will  be  partially  or  fully  offset  against  the  user's  obligations  under  the 
transmission  contract.  Any  remaining  monetary  obligations  shall  be  settled  by  the  debtor,  with 
payment terms in accordance with the act governing the calculation of network charges. 

202 Although the OS+BB mechanism is foreseen in the regulation, the FDA UIOLI has been applied in practice at the IPs. 

203  The  mechanism  is  described  in  the  “Rules  on  the  conditions  and  method  of  capacity  allocation  at  transmission  system 
interconnection points” (link). 

168 

            
       
 
 
 
If the amount of capacity offered by the network users is not sufficient to cover the capacity needs 
at the IP, the TSO reduces the nominations of the users proportionately to the capacity that cannot 
be served. 

Firm day ahead use-it-or-lose-it204 

If ACER’s  Congestion Report indicates that an IP is contractually congested, the TSO must apply 
the firm day ahead use-it-or-lose-it mechanism for a period of one year, starting on 1st March. The 
TSO must notify the network users and the NRA of this decision. 

With the activation of the mechanism at an IP, the following restrictions apply to the renominations 
of the network users for that IP: 

•  Nominations may be revised down to a minimum of 10% and up to a maximum of 90% of 

the booked capacity at the IP. 

• 

• 

If the initial nomination exceeded 80% of the user’s booked capacity, upward revisions may 
reach up to half of the unannounced volume, while downward revisions are allowed to a 
minimum 10% of the booked capacity. 

If  the  initial  nomination  did  not  exceed  20%  of  the  user’s  booked  capacity,  downward 
revisions may be up to half of the nominated volume, while upward revisions are allowed 
to a maximum of 90% of the booked capacity. 

The restricted capacity is offered by the TSO as part of the available firm capacity in the capacity 
auctions  of  the  IP.  The  network  users  may  use  the  restricted  part  of  their  booked  capacity  as 
interruptible. 

The above restrictions do not apply to network users who, in the previous calendar year, had booked 
less than 10% of the average technical capacity at the IP. 

If ACER’s Congestion Report indicates that the conditions described above are unlikely to occur over 
the  next  3  years  due  to  available  capacity,  the  TSO  may  suspend  the  implementation  of  the 
mechanism. 

Surrender of capacity205 

In the event of contractual congestion, a network user may surrender its booked firm capacity at 
an IP to the TSO. Only capacity products with a duration longer than one day can be surrendered. 
The user must notify the TSO that it is surrendering capacity at least 3 working days before the 
intended date of capacity surrender.  

The TSO makes the surrendered capacity available in the primary capacity market for the relevant 
IP and allocates it after the available capacity has been booked. 

The network user is allowed to offer the surrendered capacity in the secondary market. If the user 
sells the surrendered capacity in the secondary market after receiving confirmation of the surrender 
from the TSO, then the user must immediately notify the TSO accordingly, so that the TSO does 
not offer this capacity in the primary market. 

204  The  mechanism  is  described  in  the  “Rules  on  the  conditions  and  method  of  capacity  allocation  at  transmission  system 
interconnection points” (link). 

205  The  mechanism  is  described  in  the  “Rules  on  the  conditions  and  method  of  capacity  allocation  at  transmission  system 
interconnection points” (link). 

169 

            
       
 
 
 
Until  the  TSO  reallocates  the  surrendered  capacities,  the  network  user  retains  all  rights  and 
obligations under the original transmission contract. These rights and obligations shall also apply to 
any portion of the capacities that remain unallocated by the TSO. 

If  more  than  one  user  surrender  capacity  at  an  IP  for  the  same  period,  then  the  capacity  is 
reallocated on a first-come first-served basis. 

Long-term use-it-or-lose-it206 

The  TSO  is  required  to  provide  the  NRA  with  data  for  each  IP  on  the  daily  utilization  of  booked 
capacities  under  transmission  contracts  valid  for  periods  longer  than  one  year,  as  well  as  under 
shorter-term contracts that collectively cover a continuous period of at least 2 years. The TSO must 
report to the NRA twice per year: 

•  By 15th November, the TSO reports on the period from 1st April to 30th September of the 

same year. 

•  By 15th May each year, the TSO shall report on the period from 1st October of the previous 

year to 31st March of the current year. 

After reviewing the data provided by the TSO, the NRA may issue a decision requiring the partial or 
full withdrawal of a network user’s capacity at an IP in case the user is systematically underutilizing 
it. In this case, the TSO must notify the impacted user. The withdrawal may be for part or the whole 
capacity booked by the user, and for a specific period of for the remainder of the user’s contractual 
period. 

The TSO offers the withdrawn capacity at the IP in the primary capacity market. This capacity can 
be sold after the available capacity and any surrendered capacity at the IP have been allocated.  

The network user having its capacity withdrawn retains its rights and obligations under the original 
transmission contract until this capacity is reallocated by the TSO to another user. These rights and 
obligations also apply to any capacities that remain unallocated by the TSO. 

206  The  mechanism  is  described  in  the  “Rules  on  the  conditions  and  method  of  capacity  allocation  at  transmission  system 

interconnection points” (link). 

170 

            
       
 
 
 
 
 
 
Spain 

Overview of CMP Guidelines application207 

CMP 

OS+BB 

FDA-UIOLI 

Surrender 

LT-UIOLI 

IPs with 
Member States 

IPs with third 
countries 

Interface with 
LNG terminals / 
UGSs 

Offtakes to 
distribution 

Offtakes to 
consumers 

 

- 

 

 

- 

- 

 

 

- 

- 

 

 

- 

- 

- 

- 

- 

- 

- 

- 

Oversubscription and buy-back at the European VIPs208 

An OS+BB scheme applies at the VIPs Pirineos and Iberico, in accordance with joint decisions of 
the TSO with the adjacent French and Portuguese TSOs, respectively. Each of the joint decisions 
determines the main principles for offering additional firm capacity at the VIP beyond the technical 
capacity  at  the  network  point,  the  methodology  and  procedure  for  calculating  the  additional 
capacity, the buy-back procedure and the pricing for the capacity at the VIP. The mechanism applies 
only to bundled capacity at the VIP. 

The TSO, in collaboration with the adjacent TSOs, estimates the expected utilization of capacity at 
the  respective  VIP,  considering  factors  such  as  contracted  capacity,  scheduling,  nominations, 
historical utilization, and the risks for possible buy-back of the additional capacity. Depending on 
the expected utilization on a given gas day, the TSO may offer additional firm capacity at the VIP.  

The  additional  capacity  is  offered  as  a  daily  standard  firm  capacity  product,  together  with  the 
available capacity (without any distinctions), at the respective capacity auction.  

If the total nominations at the VIP on a gas day exceed its technical capacity, and technical and 
market measures (interruption of interruptible capacities, management of the operating balancing 
account) are not sufficient to meet demand for capacity, then the TSO activates, together with the 
adjacent TSO, the buy-back procedure. The network users that have nominated capacity at the VIP 
on the gas day may enter the buy-back auction, conducted at the secondary market of the PRISMA 
booking platform, and sell their capacity back to the TSOs. The TSOs must announce the amount 
of capacity that needs to be bought back, the maximum price at each side of the VIP, and the list 
of network users that can take part in the auction. At the Spanish side, the price at which capacity 
is offered by the users cannot exceed the daily reserve price for the gas day, multiplied by a factor 
of 1.25.  

The offers from the network users are ranked according to the price, with the lowest price ranking 
first. In case the capacity bought back from the users is not sufficient to cover all capacity needs at 
the  VIP,  the  TSOs  reduce  the  users’  capacity  proportionately  to  their  submitted  nominations.  In 
such a case, the TSOs must compensate the network users for the reduced capacity, using the daily 
reference price applied on that gas day. 

207 European CMP Guidelines are mandatory only at European IPS. The other infrastructures are subject to national legislation, 

which, in Spain, develops similar CMPs. 

208 The mechanism is described in the Circular 1/2013 of the National Commission of Markets and Competition (link), “Joint 

Decision of Enagás, REN and TIGF (2016) on an oversubscription and buy-back scheme” (link), and “Enagás and TIGF 
(2017) Procedure for the implementation of the oversubscription and buy-back scheme” (link). 

171 

            
       
 
 
 
Surrender of capacity at the European VIPs 209 

The network users have the right to surrender to the TSO their firm capacity booked at IPs, with 
the  exception  of  capacity  products  with  a  duration  of  one  day  or  less.  The  users  may  surrender 
booked capacity partially or in whole, for the full contract term or for a specific period. Both bundled 
and unbundled capacity can be surrendered, however bundled capacity can only be surrendered as 
bundled capacity. The capacity surrendered by a user cannot be made available in the secondary 
market  between  the  user’s  notification  to  the  TSO  and  the  result  of  the  auction  at  which  the 
surrendered capacity is being offered. 

The  TSO  sells  the  surrendered  capacity  in  the  primary  market,  through  quarterly  firm  product 
auctions (up to four consecutive quarters) and monthly firm products auctions. The capacity is made 
available in the next auctions, provided that it has been surrendered at least 15 days before the 
subsequent  quarterly  auction  in  the  case  of  quarterly  firm  product  auctions  and  10  days  for  the 
monthly products auctions. Surrender capacity is reallocated only after all available firm capacity 
at  the  IP  has  been  sold,  and  before  the  reallocation  of  capacity  released  through  the  LT  UIOLI 
mechanism. 

The original network user retains all associated rights and obligations for the surrendered capacity, 
including  the  obligation  to  pay  network  charges,  until  the  capacity  has  been  reallocated.  If  the 
capacity is reallocated to another network user at a price lower than the original tariff, then the 
user surrendering its capacity must pay the difference, without any cost to the TSO. 

If multiple users surrender capacity for the same period, reallocation is carried out on a first-come 
first-served basis. If users surrendered this capacity on the same day, this is allocated on a pro-
rata basis. 

Long-term use-it-or-lose-it at the European VIPs210 

The TSO has agreed with the adjacent Portuguese TSO on a joint implementation of the LT UIOLI 
mechanism  at  VIP  Iberico.  This  includes  a  common  approach  on  the  key  elements  of  the 
mechanism, such as the monitoring requirements for the use of capacity, criteria for systematically 
underutilized capacity, the withdrawal of capacity and its offering to the primary market. 

Each year, in April, the TSO must calculate the use of capacity by the network users at the VIP and 
inform the NRA. For this purpose, the TSO determines the level of utilization of capacity for each 
user for each of the following periods (monitoring periods): 

• 

• 

From 1st April to 30th September of the preceding year. 

From 1st October of the preceding year to 31st May of the current year. 

The TSO must activate the use-it-or-lose-it mechanism in case it identifies cases of network users 
holding long-term capacity rights, with duration of one or more years subsequent to the current 
gas year, both yearly and quarterly (four consecutive quarters) products, which underutilize their 
booked  capacity.  Capacity  is  considered  as  being  underutilized  in  case  the  following  conditions 
apply: 

•  Use of booked capacity is on average during both monitoring periods below 80%. 

• 

In both periods there were at least 60 days at which the user nominated above 80% of its 
booked capacity and then renominated half or less than its initial nomination.  

209 The mechanism is described in the “Circular 1/2013 of the National Commission of Markets and Competition” (link). 

210 The mechanism is described in the “Circular 1/2013 of the National Commission of Markets and Competition” (link). 

172 

            
       
 
 
 
Capacity is not considered as being underutilized if the network user has proven that it offered the 
capacity at the secondary market under reasonable conditions. Offering of capacity at the secondary 
market is considered reasonable if the price at which the capacity was made available was equal to 
or lower than the highest between the auction reserve price at the time of the offer, the price at 
which the capacity was booked, and the market price for the capacity. 

If the TSO identifies a case of underutilization, it notifies the affected network user. If the latter 
justifies  why  the  booked  capacity  was  not  used  or  proves  that  the  capacity  was  offered  at  the 
secondary  market  under  reasonable  conditions,  then  the  particular  case  is  not  considered  as 
underutilization.    

By the end of May, the TSO must, in coordination with the adjacent Portuguese TSO, inform the 
network users underutilizing their capacity. If the user fails to justify the underutilization, the TSO 
withdraws, for the subsequent gas year, the portion of the booked capacity for the next year that 
corresponds to the lowest level of underutilization from the two preceding monitoring periods.  

The  withdrawn  capacity  is  offered  in  the  primary  market,  first  as  quarterly  and  subsequently  as 
monthly  standard  firm  products,  until  it  has  been  fully  reallocated.  The  withdrawn  capacity  is 
reallocated only after all available capacity and any surrendered capacity at the VIP have been sold. 
The network user having its capacity withdrawn may not offer this capacity in the secondary market, 
15  days  before  the  auction  for  quarterly  capacity  and  10  days  before  the  auction  for  monthly 
capacity. 

If the capacity of multiple users has been withdrawn, and demand for capacity does not allow all 
the withdrawn capacity to be sold, then the capacity is reallocated on a pro-rata basis. 

The  network  user  having  its  capacity  withdrawn  retains  its  rights  and  obligations  under  the 
transmission  contract,  until  the  capacity  has  been  reallocated.  If  the  capacity  is  reallocated  at  a 
lower  price  than  the  original  one,  then  the  network  user  must  compensate  the  TSO  for  the 
difference. 

In the interconnections between France and Spain, this mechanism has been defined separately by 
every  TSO  at  each  side  of  the  VIP.  Triggering  conditions  applied  on  the  Spanish  side  (the  same 
conditions than the applied at the interconnections with Portugal) are different than the triggering 
conditions applied on the French side.  

Management of congestion at LNG terminals211 

The congestion management measures applied at the LNG terminals include a long-term use-it-or-
lose-it mechanism, an oversubscription and buy-back mechanism and a surrender mechanism212. 
Table  32  provides  an  overview  of  the  congestion  management  procedures  and  anti-hoarding 
measures for LNG terminals, for each service. 

211 The mechanism is described in the “Resolution of March 24, 2022” (link) and the “Circular 8/2019 of December 12, of 

CMCM” (link). 

212 A short-term use-it-or-lose-it mechanism also applies for truck loading at the terminals. 

173 

            
       
 
 
 
Table 32: Congestion management procedures and anti-hoarding measures (LNG terminals) 

LT UIOLI 

Short-term UIOLI 

•  Regasification 
•  LNG storage 
•  Truck loading (by 
LNG terminal) 
•  Virtual liquefaction 
•  Entry to VBP 

•  Exit from VBP 

General procedure: 
•  Regasification 
•  Virtual liquefaction 
•  Entry to VBP 
•  Exit from VBP 
Specific procedure: 
•  Truck loading (by 
LNG terminal) 

Anti-hoarding 
measures applied to 
LNG loading and 
unloading services 

•  Vessel unloading 
•  LNG loading form 
plant to vessel 
•  Transhipment 
•  Cooling down 

OS+BB 

•  LNG storage 

The LT UIOLI mechanism used for the services of regasification, LNG storage, truck loading, virtual 
liquefaction, entry to and exit from the virtual balancing point. It only applies if 90% of the specific 
services’ capacity has been contracted at a terminal. 

In October of each year, the TSO and terminal operator must calculate the utilization of capacity by 
the terminal users for each service during the previous gas year. Capacity of a service is considered 
underutilized if: 

• 
• 

It is below 80%, except for truck loading for which the threshold is 60%, or 
The terminal user nominated over 80% of its booked capacity and then renominated less 
than half of what was initially nominated for at least 60 days (the threshold for truck loading 
is 60%).  

Capacity that was surrendered by the user or offered in the secondary market at a price equal to 
or less than zero, will not be taken into account when calculating utilization. 

If the capacity of a service is underutilized, the terminal operator withdraws the user’s capacity. 
The withdrawal applies for the underutilized part of capacity, to all annual and quarterly products 
booked by the user for the subsequent gas year. The user will retain its rights and obligations until 
the withdrawn capacity has been reallocated. 

Terminal users have the right to surrender their capacity for capacity products involving a slot (ship 
unloading and loading, shit-to-ship transfer, ship cooling) and the rest of services, which are offered 
as  standard  products,  except  for  within  day  products.  Capacity  can  be  surrendered  in  whole  or 
partially, for the full contract term or for a specific period. Bundled capacity can only be surrendered 
as bundled. The user will retain its rights and obligations until the surrendered capacity has been 
reallocated. If the capacity is reallocated to another user at a price lower than the original tariff, 
then the user surrendering its capacity must pay the difference.  

In specific case of slots, if a terminal user does not use its booked slots, and does not provide a 
notice to the terminal operator at least one month in advance, surrendering it or offering it in the 
secondary market, then the user must pay the following penalties: 

•  Notice between 21  and  30  days  in  advance:  The  user  pays 5  times  the  fixed part  of  the 

tariff 

•  Notice between 11  and  20  days  in  advance:  The  user  pays 7  times  the  fixed part  of  the 

tariff 

•  Notice between 0  and 10 days  in  advance:  The  user  pays 10  times  the  fixed part  of  the 

tariff 

174 

            
       
 
 
 
 
In case the tariff does not have a fixed term, the surcharge is applied on the variable term multiplied 
by the contracted capacity. CNMC is currently reviewing these congestion mechanisms for possible 
adjustments. 

An OS+BB scheme applies to unbundled LNG storage services at the terminals. The methodology 
for  calculating  additional  capacity  to  be  offered  considers  the  expected  usage  level  of  booked 
capacity, including factors such as scheduled infrastructure use, historical usage data, submitted 
regasification,  virtual  liquefaction  and  truck  loading  nominations,  and  the  risks  of  the  operator 
having to buy back capacity. This additional capacity is offered on a daily basis together with the 
available capacity. 

The TSO decides whether there is a need to buy back any previously contracted additional capacity. 
Buy  back  is  conducted  preferably  through  an  auction.  The  TSO  must  notify  the  users  holding 
capacity  of  the  capacity  needs,  calling  them  to  submit  offers  for  selling  their  capacity.  The  offer 
must define the buy-back price, which is capped to 1.25 times the corresponding tariff. The TSO 
accepts the offers following a lowest price first principle. If the amount of capacity bought back is 
not sufficient, the capacity is bought back on a pro-rata basis from all users based on the capacity 
they are holding, at the regulated tariff. 

Lastly,  two  ST  UIOLI  procedures  are  defined  (CNMC’s  Resolutions):  a  general  procedure  for 
regasification,  virtual  liquefaction,  entry  to  VBP  and  exit  from  VBP,  and  one  specific  for  truck 
loading). These mechanisms, which consist of a limitation of renomination rights, only apply if the 
booking level is 95% or higher. 

Management of congestion at underground storage facilities213 

An OS+BB scheme applies to storage, injection and withdrawal services at the underground storage 
facilities. The scheme is the same as in LNG terminals. The methodology for calculating additional 
capacity to be offered considers the expected usage level of booked capacity, including factors such 
as scheduled infrastructure use, historical usage data, submitted nominations, and the risks of the 
operator having to buy back capacity. This additional capacity is offered together with the available 
capacity. However, it is allocated to users after these primary capacities have been allocated. 

The TSO decides whether there is a need to buy back any previously contracted additional capacity. 
Buy  back  is  conducted  preferably  through  an  auction.  The  TSO  must  notify  the  users  holding 
capacity  of  the  capacity  needs,  calling  them  to  submit  offers  for  selling  their  capacity.  The  offer 
must define the buy-back price, which is capped to 1.25 times the corresponding tariff. The TSO 
accepts the offers following the lowest price first principle. If the amount of capacity bought back is 
not sufficient, the capacity is bought back on a pro-rata basis from all users based on the capacity 
they are holding, at the regulated tariff. 

Use of congestion revenues 

The  revenues  generated  from  capacity  allocation  mechanisms  are  managed  in  accordance  with 
established regulatory guidelines. Premiums obtained from capacity auctions are considered income 
of  the  gas  system  and  are  used  to  reduce  tariffs  in  the  subsequent  regulatory  period.  Penalties 
resulting from non-compliance with system rules are paid directly to the TSO.  

Out of the revenues and costs deriving from the application of the oversubscription and buy-back 
mechanism, at European VIPs, 90% are allocated to the to the gas system (reduction of network 
charges), while the remaining 10% is retained by TSO.  

213 The mechanism is described in Resolution of March 24, 2022 (link). 

175 

            
       
 
 
 
 
Annex II: List of network points’ sides analysed 

Network points analysed 

TSO 
Amber Grid 
Amber Grid 
bayernets 
bayernets 
bayernets 
bayernets 
bayernets 
Bulgartransgaz 
Bulgartransgaz 
Bulgartransgaz 
Conexus 
DESFA 
DESFA 
DESFA 
Enagas 
Enagas 
Enagas 
Enagas 
Energinet 
Energinet 
eustream 
eustream 
FGSZ 
FGSZ 
FGSZ 
FGSZ 
FGSZ 
FGSZ 
Fluxys Belgium 
Fluxys Belgium 
Fluxys Belgium 
Fluxys Belgium 
Fluxys Belgium 
Fluxys Deutschland 
Fluxys Deutschland 
Fluxys TENP 
Fluxys TENP 

IP name 
Kiemenai 
Santaka 
RC Lindau 
Überackern ABG (AT) / Überackern (DE) 
Überackern SUDAL (AT) / Überackern 2 (DE) 
Überackern SUDAL (AT) / Überackern 2 (DE) 
VIP Kiefersfelden-Pfronten 
Kulata (BG) / Sidirokastron (GR) 
Kulata (BG) / Sidirokastron (GR) 
Kyustendil (BG)/Zidilovo (MK) 
Kiemenai 
Kulata (BG) / Sidirokastron (GR) 
Kulata (BG) / Sidirokastron (GR) 
Nea Mesimvria 
VIP IBERICO 
VIP IBERICO 
VIP PIRINEOS 
VIP PIRINEOS 
VIP DK-THE 
VIP DK-THE 
Baumgarten 
Balassagyarmat (HU) / Velké Zlievce (SK) 
Csanadpalota 
Csanadpalota 
Mosonmagyarovar 
Balassagyarmat (HU) / Velké Zlievce (SK) 
Kiskundorozsma 2 
VIP Bereg 
VIP THE-ZTP 
VIP-BENE 
VIRTUALYS 
Zeebrugge IZT 
Eynatten 1 (BE) // Lichtenbusch / Raeren (DE) 
Greifswald / Fluxys Deutschland 
Lubmin II 
VIP Germany-CH 
VIP Germany-CH 

Direction 
exit 
entry 
exit 
entry 
entry 
exit 
exit 
entry 
exit 
exit 
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entry 
exit 
entry 
entry 
exit 
entry 
exit 
entry 
exit 
exit 
entry 
entry 
exit 
entry 
entry 
entry 
exit 
exit 
exit 
entry 
entry 
exit 
entry 
entry 
entry 
exit 

Adjacent TSO 

GAZ-SYSTEM 

GCA 
GCA 
GCA 

DESFA 
DESFA 

Bulgartransgaz 
Bulgartransgaz 
TAP AG 

TERÉGA 

GCA 
FGSZ 
Transgaz 
Transgaz 
GCA 
eustream 

OGE 
GTS 
GRTgaz 
Interconnector 
GASCADE  

EIC Code 
21Z000000000153U 
21Z180960164W65R 
21Z000000000252S 
21Z000000000002E 
21Z0000000001240 
21Z0000000001240 
21Z0000000002895 
21Z000000000020C 
21Z000000000020C 
21Z000000000137S 
21Z000000000153U 
21Z000000000020C 
21Z000000000020C 
21Z000000000473C 
21Z000000000282J 
21Z000000000282J 
21Z000000000285D 
21Z000000000285D 
21Z8273645914289 
21Z8273645914289 
21Z8273645914289 
21Z000000000358C 
21Z000000000236Q 
21Z8273645914289 
21Z000000000003C 
21Z000000000358C 
21Z000000000505P 
21Z000000000507L 
21Z102938475601E 
21Z000000000503T 
21Z0000000004847 
21Z0000000000074 
21Z0000000000155 
21Z000000000255M 
21Z0000000004790 
21Z0000000004960 
21Z0000000004960 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Gas Connect Austria  Baumgarten (WAG) 
Gas Connect Austria  Baumgarten (WAG) 
Gas Connect Austria  Mosonmagyarovar 
Gas Connect Austria  Murfeld (AT) / Ceršak (SI) 
Gas Connect Austria  Oberkappel 
Gas Connect Austria  Oberkappel 
Gas Connect Austria  Überackern ABG (AT) / Überackern (DE) 
Gas Connect Austria  Überackern ABG (AT) / Überackern (DE) 
Gas Connect Austria  Überackern SUDAL (AT) / Überackern 2 (DE) 
Gas Connect Austria  Überackern SUDAL (AT) / Überackern 2 (DE) 
GASCADE  
GASCADE  
GASCADE  
GASCADE  
GASCADE  
GASCADE  
GASCADE  
GASCADE  
GASCADE  
Gastransport Nord 
Gastransport Nord 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GUD 
GAZ-SYSTEM (ISO) 
GAZ-SYSTEM 
GAZ-SYSTEM 
GAZ-SYSTEM 
GRTgaz Deutschland  VIP France - Germany 
GRTgaz Deutschland  VIP France - Germany 

Deutschneudorf EUGAL Brandov 
Eynatten 1 (BE) // Lichtenbusch / Raeren (DE) 
Eynatten 1 (BE) // Lichtenbusch / Raeren (DE) 
Lubmin II 
Mallnow 
Mallnow 
Olbernhau (DE) / Hora Svaté Kateřiny (CZ) 
VIP Brandov 
VIP Brandov 
Bunde (DE) / Oude Statenzijl (L) (NL) (GTG Nord) 
Bunde (DE) / Oude Statenzijl (L) (NL) (GTG Nord) 
Bunde (DE) / Oude Statenzijl (H) (NL) (GUD) 
Deutschneudorf EUGAL Brandov 
Dornum / NETRA (GUD) 
Dornum / NETRA (GUD) 
Ellund (GUD) 
Ellund (GUD) 
Emden (EPT1) (GUD) 
Emden (EPT1) (GUD) 
Greifswald / GUD 
Lubmin II 
VIP DK-THE 
VIP DK-THE 
VIP TTF-GASPOOL H 
VIP TTF-GASPOOL H 
VIP-TTF-THE-H 
VIP-TTF-THE-H 
Mallnow 
Cieszyn (PL) / Český Těšín (CZ) 
Santaka 
GCP GAZ-SYSTEM/UA TSO 

entry 
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entry 
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entry 
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exit 
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exit 

21Z000000000163R 
21Z000000000163R 
21Z000000000003C 
21Z0000000000058 
21Z000000000001G 
21Z000000000001G 
21Z000000000002E 
21Z000000000002E 
21Z0000000001240 
21Z0000000001240 
21Z0000000004839 
21Z0000000000155 
21Z0000000000155 
21Z0000000004790 
21Z000000000056S 
21Z000000000056S 
21Z000000000092O 
21Z0000000004863 
21Z0000000004863 
21Z000000000079G 
21Z000000000079G 
21Z000000000076M 
21Z0000000004839 
21Z000000000053Y 
21Z000000000053Y 
21Z000000000144V 
21Z000000000144V 
21Z0000000000511 
21Z0000000000511 
21Z000000000255M 
21Z0000000004790 
21Z8273645914289 
21Z8273645914289 
21Z000000000500Z 
21Z000000000500Z 
21Z0019743987060 
21Z0019743987060 
21Z000000000056S 
21Z000000000239K 
21Z180960164W65R 
21Z000000000508J 
21Z0000000004928 
21Z0000000004928 

FGSZ 

OGE 

bayernets 
OGE 
bayernets 
bayernets 

Nord Stream 2 
GAZ-SYSTEM (ISO) 

Gassco 

Gassco 

Nord Stream 
Nord Stream 2 

GASCADE 
N4G 
Amber Grid 
Gas TSO UA 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
GRTgaz 
GRTgaz 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 

GTS 

GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
GTS 
ICGB 
ICGB 
NEL Gastransport 
NET4GAS 
NET4GAS 
NET4GAS 
NET4GAS 
ONTRAS 
ONTRAS 

VIRTUALYS 
Obergailbach (FR) / Medelsheim (DE) 
Bocholtz 
Bunde (DE) / Oude Statenzijl (H) (NL) (GUD) 
Bunde (DE) / Oude Statenzijl (H) (NL) (GUD) 
Bunde (DE) / Oude Statenzijl (H) (NL) I (OGE) 
Bunde (DE) / Oude Statenzijl (H) (NL) I (OGE) 
Emden (EPT1) (GTS) 
Emden (EPT1) (GTS) 
Hilvarenbeek 
Hilvarenbeek 
's Gravenvoeren Dilsen (BE) // 's Gravenvoeren/Obbicht 
(NL) 
Tegelen 
VIP BENE-L 
VIP BENE-L 
VIP TTF-GASPOOL H 
VIP TTF-GASPOOL H 
VIP TTF-GASPOOL L 
VIP TTF-GASPOOL L 
VIP TTF-NCG H 
VIP TTF-NCG H 
VIP TTF-NCG L 
VIP TTF-NCG L 
VIP TTF-THE-H 
VIP TTF-THE-H 
VIP TTF-THE-L 
VIP TTF-THE-L 
VIP BENE 
VIP BENE 
Winterswijk 
Zelzate 
Zelzate 
Zevenaar 
Komotini - TAP / IGB 
Stara Zagora 
Greifswald / NEL 
Lanžhot 
VIP Brandov 
VIP Waidhaus 
VIP Waidhaus 
Deutschneudorf EUGAL Brandov 
GCP GAZ-SYSTEM/ONTRAS 

exit 
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exit 

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entry 
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entry 
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entry 
exit 
entry 
exit 
entry 
entry 
exit 
exit 
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21Z0000000004847 
21Z000000000039S 
21Z000000000071W 
21Z000000000076M 
21Z000000000076M 
21Z000000000075O 
21Z000000000075O 
21Z000000000055U 
21Z000000000055U 
21Z000000000243T 
21Z000000000243T 

21Z000000000169F 

21Z000000000117Y 
21Z000000000534I 
21Z000000000534I 
21Z000000000500Z 
21Z000000000500Z 
21Z000000000499V 
21Z000000000499V 
21Z000000000502V 
21Z000000000502V 
21Z000000000501X 
21Z000000000501X 
21Z0019743987060 
21Z0019743987060 
21Z012965309364T 
21Z012965309364T 
21Z000000000503T 
21Z000000000503T 
21Z000000000073S 
21Z000000000019Y 
21Z000000000019Y 
21Z000000000072U 
21Z000000000472E 
58Z-IP-00034-STZ 
21Z000000000255M 
21Z000000000061Z 
21Z0000000004863 
21Z000000000489Y 
21Z000000000489Y 
21Z0000000004839 
21Z000000000456C 

Fluxys Belgium 
OGE 

Fluxys Belgium 

Fluxys Belgium 

Thyssengas 
Fluxys Belgium 

Nord Stream 

OGE 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ONTRAS 
ONTRAS 
ONTRAS 
ONTRAS 
OPAL Gastransport 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Open Grid Europe 
Plinacro Ltd 
Plinovodi 
Plinovodi 
REN - Gasodutos 
REN - Gasodutos 
Snam Rete Gas 
Snam Rete Gas 
TAG 
TAG 
TAG 
TAP 
TAP 
TAP 
TERÉGA 
TERÉGA 
terranets bw 
terranets bw 
Thyssengas 
Thyssengas 
Thyssengas 

GCP GAZ-SYSTEM/ONTRAS 
Hora Svaté Kateřiny (CZ) / Deutschneudorf (Sayda) (DE) 
Hora Svaté Kateřiny (CZ) / Deutschneudorf (Sayda) (DE) 
Lubmin II 
Greifswald / OPAL 
Dornum / NETRA (OGE) 
Dornum / NETRA (OGE) 
Dornum GASPOOL 
Dornum GASPOOL 
Ellund (OGE) 
Ellund (OGE) 
Emden (EPT1) (OGE) 
Emden (EPT1) (OGE) 
Remich 
Remich 
VIP Oberkappel 
VIP Oberkappel 
VIP THE-ZTP 
VIP THE-ZTP 
VIP TTF-NCG H 
VIP TTF-NCG H 
VIP Waidhaus 
VIP Waidhaus 
Rogatec 
Murfeld (AT) / Ceršak (SI) 
Rogatec 
VIP IBERICO 
VIP IBERICO 
Melendugno - IT / TAP 
Tarvisio (IT) / Arnoldstein (AT) 
Baumgarten (TAG) 
Tarvisio (IT) / Arnoldstein (AT) 
Tarvisio (IT) / Arnoldstein (AT) 
Kipoi 
Melendugno - IT / TAP 
Nea Mesimvria 
VIP PIRINEOS 
VIP PIRINEOS 
RC Basel 
RC Lindau 
Emden (EPT1) (Thyssengas) 
Epe (DE) (KGE) / Gronau Epe 11 (UGS-E) 
Epe (DE) (Trianel) / Epe (UGS-E) III (Thyssengas) 

exit 
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entry 

21Z000000000456C 
21Z0000000000228 
21Z0000000000228 
21Z0000000004790 
21Z000000000241X 
21Z000000000053Y 
21Z000000000053Y 
21Z0000000004855 
21Z0000000004855 
21Z0000000000260 
21Z0000000000260 
21Z0000000000503 
21Z0000000000503 
21Z0000000000406 
21Z0000000000406 
21Z000000000490C 
21Z000000000490C 
21Z102938475601E 
21Z102938475601E 
21Z000000000502V 
21Z000000000502V 
21Z000000000489Y 
21Z000000000489Y 
21Z000000000128T 
21Z0000000000058 
21Z000000000128T 
21Z000000000282J 
21Z000000000282J 
21Z000000000474A 
21Z000000000004A 
21Z000000000164P 
21Z000000000004A 
21Z000000000004A 
21Z0000000004758 
21Z000000000474A 
21Z000000000473C 
21Z000000000285D 
21Z000000000285D 
21Z000000000253Q 
21Z000000000252S 
21Z000000000145T 
21Z000000000367B 
21Z000000000366D 

Nord Stream 2 
Nord Stream 
Gassco 

Gassco 

Fluxys Belgium 

Plinovodi 
GCA 
Plinacro 

TAP AG 
TAG GmbH 

SNAM RETE GAS 

TANAP 
SNAM RETE GAS 
DESFA S.A. 
Enagas 

Gassco 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Thyssengas 
Thyssengas 

Thyssengas 

Thyssengas 

Thyssengas 
Thyssengas 
Thyssengas 
Transgaz 
Transgaz 

Epe (DE) (Uniper) H-Gas / Gronau Epe 13 (UGS-E) 
Epe/Xanten I (UGS-E) 
Jemgum (DE) (EWE) / Leer Mooräcker 3 (700096 Jemgum I 
UGS-E) 
Nüttermoor (DE) (EWE) H / Leer Mooräcker 1 (700096 
Nüttermoor H UGS-E) 
VIP TTF-THE-L 
VIP TTF-THE-L 
Zevenaar (Thyssengas) 
Csanadpalota 
Csanadpalota 

entry 
entry 

entry 

entry 

entry 
exit 
entry 
entry 
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21Z000000000370M 
21Z000000000481D 

21Z0000000002879 

21Z000000000284F 

21Z012965309364T 
21Z012965309364T 
21Z000000000072U 
21Z000000000236Q 
21Z000000000236Q 

GTS 

FGSZ 
FGSZ 

Dual model IP sides analysed 

TSO 

IP name 

Direction  Description 

GASCADE 
Gastransport 

Deutschneudorf EUGAL Brandov 

exit 

GASCADE 
Gastransport 

Olbernhau (DE) / Hora Svaté 
Kateřiny (CZ) 

Gastransport 
Nord 

Bunde (DE) / Oude Statenzijl 
(L) (NL) (GTG Nord) 

Gastransport 
Nord 

Bunde (DE) / Oude Statenzijl 
(L) (NL) (GTG Nord) 

exit 

entry 

exit 

Gasunie 
Deutschland 

Deutschneudorf EUGAL Brandov 

exit 

GTS 

GTS 

Bocholtz 

s Gravenvoeren Dilsen (BE) // 's 
Gravenvoeren/Obbicht (NL) 

exit 

exit 

As of Jan 1, 2020, all capacity at the IP is offered at the VIP Brandov-GASPOOL 
(Gascade). Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP) 
As of Nov 1, 2018, all capacity at the IP Olbernhau II is offered at the VIP 
Brandov-GASPOOL (Gascade). Only data for CMPs applied to past contracts is 
available at ENTSOG’s TP (Dual model IP) 
As of Oct 1, 2021, all capacity at IP Oude Statenzijl is offered at VIP TTF-THE-L 
operated by Thyssengas214. Only data for CMPs applied to past contracts is 
available at ENTSOG’s TP (Dual model IP) 
As of Oct 1, 2021, all capacity at IP Oude Statenzijl is offered at VIP TTF-THE-L 
operated by Thyssengas. Only data for CMPs applied to past contracts is 
available at ENTSOG’s TP (Dual model IP) 
Validity ended in 31/12/2022. All capacity was merged at the VIP Brandov-
GASPOOL. GASCADE, Fluxys, GUD, ONTRAS and OGT agreed that GASCADE 
shall be the operator of the VIP Brandov-GASPOOL215. Only data for CMPs 
applied to past contracts is available at ENTSOG’s TP (Dual model IP).  
Initially in Ap 1 2020 the IP was merged into VIP TTF-NCG-H216. Then, as of Apr 
1, 2022, capacity merged at VIP TTF-THE-H217. Only data for CMPs applied to 
past contracts is available at ENTSOG’s TP (Dual model IP).  
In VIP BENE. Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP).  

214 https://www.gasunie.de/en/transparency/capacity-products/virtual-interconnection-points-vip  

215 https://www.net4gas.cz/files/verejne-konzultace/amendment-no-1-vip-agreement-vip-brandov-gaspool.pdf  

216 https://thyssengas.com/files/thyssengas/download/netzzugang/en/10/171019-88_VIP%20Marktinformation%2017.10.2019_NL_EN.pdf  

217 https://www.gasunietransportservices.nl/en/news/introduction-of-vip-ttf-the-h-with-trading-hub-europe-the-will-be-executed-on-1-april-2022  

 
 
 
 
 
 
 
 
 
 
GTS 

GTS 

GTS 

GTS 

GTS 

Tegelen 

Winterswijk 

Zelzate 

Zelzate 

Zevenaar 

exit 

exit 

entry 

exit 

exit 

ONTRAS 

Deutschneudorf EUGAL Brandov 

exit 

ONTRAS 

Hora Svaté Kateřiny (CZ) / 
Deutschneudorf (Sayda) (DE) 

entry 

ONTRAS 

Hora Svaté Kateřiny (CZ) / 
Deutschneudorf (Sayda) (DE) 

exit 

Thyssengas 

Zevenaar (Thyssengas) 

entry 

Initially in Ap 1 2020 the IP was merged into VIP TTF-NCG-L218. Then, as of Apr 
1, 2022, capacity merged at VIP TTF-THE-L219. Only data for CMPs applied to 
past contracts is available at ENTSOG’s TP (Dual model IP).  
In VIP TTF-THE-L from 01.10.2021220. Only data for CMPs applied to past 
contracts is available at ENTSOG’s TP (Dual model IP).  
In VIP BENE. Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP).  
In VIP BENE. Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP).  
Starting from Apr 1, 2020, the capacity of this network point is marketed in the 
VIP TTF-NCG-L221. Then, as of Apr 1, 2022, capacity merged at VIP TTF-THE-
L222. Only data for CMPs applied to past contracts is available at ENTSOG’s TP 
(Dual model IP).  
Validity ended in 31/12/2022. All capacity was merged at the VIP Brandov-
GASPOOL. GASCADE, Fluxys, GUD, ONTRAS and OGT agreed that GASCADE 
shall be the operator of the VIP Brandov-GASPOOL. Only data for CMPs applied 
to past contracts is available at ENTSOG’s TP (Dual model IP).  
All capacity was merged at the VIP Brandov-GASPOOL. GASCADE, Fluxys, GUD, 
ONTRAS and OGT agreed that GASCADE shall be the operator of the VIP 
Brandov-GASPOOL. Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP).  
All capacity was merged at the VIP Brandov-GASPOOL. GASCADE, Fluxys, GUD, 
ONTRAS and OGT agreed that GASCADE shall be the operator of the VIP 
Brandov-GASPOOL. Only data for CMPs applied to past contracts is available at 
ENTSOG’s TP (Dual model IP).  
Starting from Apr 1, 2020, the capacity of this network point is marketed in the 
VIP TTF-NCG-L223. Then, as of Oct 1, 2021, capacity merged at VIP TTF-THE-L. 
Only data for CMPs applied to past contracts is available at ENTSOG’s TP (Dual 
model IP).  

218 https://thyssengas.com/files/thyssengas/download/netzzugang/en/10/171019-88_VIP%20Marktinformation%2017.10.2019_NL_EN.pdf  

219 https://www.gasunietransportservices.nl/en/news/introduction-of-vip-ttf-the-h-with-trading-hub-europe-the-will-be-executed-on-1-april-2022  

220 https://www.entsog.eu/sites/default/files/2023-02/l_entsog_220641_NC_INT_DER_4th_IMR_05.pdf  

221 https://tron-thy.publication.virtimo.cloud/?language=en  

222 https://www.gasunietransportservices.nl/en/news/introduction-of-vip-ttf-the-h-with-trading-hub-europe-the-will-be-executed-on-1-april-2022  

223 https://tron-thy.publication.virtimo.cloud/?language=en  

 
 
 
Annex III: Case studies 

IP 

Direction 

Rationale 

IP Baumgarten 

IP Dravaszerdahely 

Slovakia to Austria 
direction 

Identified as formally congested and at which 
FDA UIOLI applies on the Austrian side and 
OS+BB at the Slovak side 

Croatia to Hungary 
direction 

This IP was congested during the energy 
crisis, resulting in the NRA applying an FDA 
UIOLI mechanism 

IP Kulata (BG) / 
Sidirokastron (GR) 

Bulgaria to Greece 
direction 

OS+BB has been offered on the Greek side 
even when the IP was utilized almost at its full 
capacity 

VIP-BENE 

VIP Pirineos 

VIP-TTF-THE-H 

Belgium to 
Netherlands direction 

Highly utilized IP, with additional capacity has 
been offered only on the Dutch side 

Spain to France 
direction 

Netherlands to 
Germany 

OS+BB was jointly applied by the TSOs. The 
offering of UBI capacity on the French side is 
also examined 

Capacity is released through oversubscription 
on the Dutch side and through FDA UIOLI on 
the German side 

Swinoujscie LNG 
terminal 

- 

Present the high utilization of the fully booked 
terminal during the examination period 

 
 
 
 
 
IP Baumgarten (Slovakia to 
Austria direction) 

During  the  examined  gas  years, 
2021/22,  2022/23  and  2023/24,  a 
large part of the technical capacity has 
been  sold  at  both  sides of  the IP.  On 
the  Slovak  side,  over  90%  of  the 
capacity  was  booked  throughout  the 
examined  period  but  never  reached 
100%. On the Austrian side, capacity 
booking  was  also  high  at  both  WAG 
and TAG entries, and on some days was fully booked at the WAG entry. Despite the fact that, most of 
the IP’s capacity was sold out, utilization was limited, and the point was never physically congested 
(Figure 40). Interruptible capacity was sold at the IP on some days, but the amount was limited and 
usually remained below 3% of the technical capacity. 

Figure 40: Use of capacity224 at Baumgarten IP225 

(a) Eustream exit 

(b) WAG entry 

224 Booked capacity beyond the IP side’s technical capacity relates to interruptible capacity sold. 

225 Source: Eustream, GCA, TAG 

 
 
 
 
 
 
(c) TAG entry 

Since 2017, ACER’s Congestion Reports have identified the Slovak side of the IP as formally congested, 
as no yearly capacity is being offered at the auctions. During the examined period, demand for firm 
capacity never exceeded the amount of capacity offered by the TSOs at the auctions taking place. This 
indicates that, although most of the capacity at the IP was booked and underutilized, there were no 
capacity requests from network users that could not be accommodated by the TSOs. Consequently, no 
contractual congestion had to be addressed at the IP.  

The figure below provides an overview of the average daily capacity released through CMPs at both IP 
sides.  On  the  Slovak  side,  some  additional  capacity  was  made  available  by  Eustream  through 
oversubscription  in 2021,  accounting  for  21%  of  the  point’s  technical  capacity.    None of  the  offered 
additional capacity was booked by network users.  On the Austrian side, the FDA UIOLI mechanism was 
applied (the mechanism applies at all Austrian IPs regardless of their congestion status), resulting in 
the  release  of  capacity  when  the  renomination  restrictions  were  activated.  At  the  WAG  entry  some  
capacity was surrendered by network users.  Specifically, around 12% of the point’s technical capacity 
was released on 4 days in October 2022, and around 1% on a single day in February 2024. 

Figure 41: Average226 amount of capacity released at Baumgarten IP through CMPs 227 

(a) Eustream exit 

(b) WAG entry 

(c) TAG entry 

During  the  examined  period,  the  FDA  UIOLI  mechanism  was  activated  most  days  at  the  WAG  entry 
point (224 days in gas year 2021/22, 362 days in gas year 2022/23 and 366 days in gas year 2023/24). 

226 The average capacity is estimated only for the days on which capacity was released through CMPs. 

227 Source: Eustream, ENTSOG 

 
 
 
 
 
 
 
 
The amount of capacity released was much lower than the unused part of the network point (Figure 42 
(a)),  it  can  therefore  be  expected  that  it  was  not necessary  to  reallocate  released  capacity  to other 
network users. Capacity was also released at the TAG entry point, but less often (177 days in gas year 
2021/22, 360 days in gas year 2022/23 and 26 days in gas year 2023/24). Most capacity was released 
between September and December 2022, but even then, the use of the network point was very limited 
(Figure 42 (b)). 

Figure 42: Capacity released through FDA UIOLI at Baumgarten IP – Austrian entry228 

(a) WAG entry 

(b) TAG entry 229 

Key findings 

•  A large part of the IP’s firm capacity has been booked during the examined period. On 

the other hand, utilization has remained low.  

• 

The Slovak side of the IP has been identified as “formally congested” in ACER’s 
Congestion Reports because no yearly capacity is being offered.  

228 Source: GCA, TAG 

229 The amount of capacity released most days that the mechanism was triggered was very small, less than 0.1% of the point’s 

technical capacity, and is not visible in the graph. 

 
 
 
 
 
 
•  Demand for capacity at the auctions was fully covered, consequently there were no 

network users with unmet capacity requests.  

•  Eustream offered additional firm capacity through oversubscription until the end of 

2021. This capacity was not booked by users. 

•  Some capacity was surrendered by network users at the WAG entry.  The capacity was 
released only on a few days (4 in 2022, 1 in 2024) and does not indicate any trends for 
using this CMP. 

IP Dravaszerdahely (Croatia to 
Hungary direction) 

to 

LNG 

terminal 

The  use  of  the  IP  changed  in  2022,  with 
network  users  requesting  capacity  at  the 
Dravaszerdahely IP to transport gas from the 
Krk 
the  Hungarian 
transmission  system.  Starting  in  April  2022, 
capacity  booked  at  both  sides  of  the  IP 
increased  and  was  fully  sold  out  for  multiple 
days.  At  the  exit  from  Croatia  firm  capacity 
was  fully  booked  for  76  days  in  gas  year 
2021/22 (all since April 2022), and 190 days in gas year 2022/23. Capacity booking remained high in 
gas  year  2023/24,  reaching  97%  -  98%  of  technical  capacity  in  the  period  from  May  to  September 
2024.  The  situation  changed  since  the  beginning  of  gas  year  2024/25,  when  contracted  capacity 
decreased considerably, dropping below 20% of the technical capacity. The figure below presents the 
evolution of the capacity use at both sides of the IP. 

Figure 43: Use of capacity at Dravaszerdahely IP230 

(a) Plinacro exit 

230 Source: Plinacro, FGSZ 

 
 
 
 
 
(b) FGSZ entry 

When  firm  capacity  was  fully  booked,  contracting  of  interruptible  capacity  was  limited.  Specifically, 
small amounts of interruptible capacity, not exceeding 8% of the IP’s technical capacity, were booked 
only for 7 days during the 3rd quarter of 2023. This indicates that the firm capacity was sufficient for 
the network users that sought to flow gas through the IP. The same conclusion can be drawn from the 
results of the capacity auctions. In the majority of cases, the firm capacity offered by the TSOs was 
sufficient  to  address  all  requests  from  network  users.  Unmet  demand  for  firm  capacity  was  only 
observed for few capacity products in 2022, including the monthly product of September 2022, and 21 
daily products, all between April and October 2022. 

A situation of contractual congestion was only observed for 18 days in September 2022. Capacity at 
the  IP  was  fully  booked,  utilization  was  below  80%  and  there  were  capacity  requests  from  network 
users for the monthly product that could not be addressed by the TSOs. Nevertheless, the IP was not 
heavily congested even that month, as utilization of the IP remained between 70% and 80% for most 
days (Figure 44).  

Figure 44: Utilization of capacity at Dravaszerdahely IP in September 2022231 

In 2023, the Croatian NRA decided to apply an FDA UIOLI mechanism at the Croatian exit of the IP, to 
facilitate the reallocation of booked but unused capacity. The average amount of firm capacity released 

231 Source: Plinacro 

 
 
 
 
 
through the CMP is presented in the figure below. On the Hungarian side, FDA UIOLI was not applied, 
as the IP did not meet the congestion criteria of the CMP Guidelines.   

Figure 45: Average232 amount of capacity released at Dravaszerdahely IP – Plinacro exit233 

So far, the reallocation restrictions of the FDA UIOLI mechanism have been activated on 48 days, 41 
in 2023 and 7 in 2024. The released capacity was reallocated only on 3 of these days, in 2023, when 
utilization of the IP side was very high. On all other days when capacity was made available through 
FDA UIOLI, there was sufficient unused capacity to accommodate all users’ flow requests (Figure 46). 

Figure 46: Capacity released through FDA UIOLI at Dravaszerdahely IP – Plinacro exit234 

Key findings 

•  Since early 2022 capacity booking and utilization at the IP have increased. As a result, 

capacity was fully booked for several days in gas years 2021/22 and 2022/23. 

232 The average capacity is estimated only for the days on which capacity was released through CMPs. 

233 Source: ENTSOG 

234 Source: ENTSOG 

 
 
 
 
 
• 

Interest for interruptible capacity was very limited. Demand for firm capacity was 
usually met by that offered by the TSOs at the auctions. Unmet demand, beyond daily 
products, was observed only for the firm capacity product of September 2022. 

•  Although the IP did not meet the contractual congestion criteria of the CMP Guidelines, 

in 2023 the Croatian NRA decided to apply an FDA UIOLI mechanism, due to the 
increasing use of the IP exit. 

• 

The FDA UIOLI mechanism has been activated on 48 days, out of which the released 
capacity was reallocated on 3 days in 2023.  

IP Kulata (BG) / Sidirokastron (GR) (Bulgaria 
to Greece direction) 

Firm capacity has been fully booked at both sides of the IP 
(DESFA entry and Bulgartransgaz exit) in the examined gas 
years  2021/22,  2022/23  and  2023/24.  Interruptible 
capacity  was  also  booked  most  days  of  each  year.  After 
mid-2023  demand  for  interruptible  capacity  increased 
considerably, and on some occasions exceeded 70% - 80% 
of the IP’s technical capacity (Figure 47). 

Figure 47: Booking of interruptible capacity at Kulata (BG) / Sidirokastron (GR) IP – DESFA Entry 235 

In  some  capacity  auctions  for  firm  monthly,  quarterly  and  yearly  products,  demand  for  capacity 
exceeded the amount of capacity offered by the TSOs. This mostly related to unbundled firm capacity 
offered by DESFA on the Greek side of the IP. The table below outlines the auction results for yearly 
and quarterly capacity during the examination period.  Notably, most interest in capacity was observed 
in  2022,  with  multiple  auction  rounds  for  unbundled  capacity  for  quarterly  products  in  gas  year 
2022/23.  

235 Source: DESFA 

 
 
 
 
 
 
Table 33: Results of capacity auctions for yearly and quarterly bundled and unbundled 236 capacity 237 

Auction 
timing 

Jul 2021 

Aug 2022 

Aug 2023 

Jul 2024 

Product 

No. of 
rounds 

No of 
participants 

No of 
contracts 

Yearly firm unbundled (GY 2021/22) 
Quarterly firm bundled (Q4-22, Q1-23, 
Q2-23, Q3-23) 
Quarterly firm unbundled (Q4-22, Q1-
23, Q2-23, Q3-23) 
Quarterly firm bundled (Q4-23) 
Quarterly firm unbundled (Q4-23) 
Yearly firm unbundled (GY 2021/22) 

3 

4 

28 

3 
2 
6 

2 

2 

3 

2 
2 
4 

2 

1 

1 

2 
1 
4 

Unmet 
demand 

1 GWh/d 

1 GWh/d 

4.9 GWh/d 

0.1 GWh/d 
8.3 GWh/d 
9.3 GWh/d 

The actual utilization of the IP varied during each gas year, as shown in the figure below. For some 
periods of time the IP was fully or almost fully used, while in others the allocated volumes remained 
well below the booked firm capacity. The IP was physically congested for 65 days in gas year 2021/22, 
32 in gas year 2022/23 and 110 in gas year 2023/24. 

Figure 48: Use of capacity238 at Kulata (BG) / Sidirokastron (GR) IP – DESFA Entry239 

Figure 49 presents the days with high and low utilization at the IP during the examined period, providing 
an  indication  of  physical  congestion  (capacity  fully  booked  and  utilized)  and  contractual  congestion 
(capacity fully booked and underutilized and unmet demand for firm capacity). In gas year 2022/23 
booked capacity was underutilized at both sides of the IP. In the other two gas years, most days with 
contractual  congestion  are  observed  on  the  Greek  side  of  the  IP,  due  to  the  unmet  demand  for 
unbundled firm yearly and quarterly capacity.  

236 Unbundled capacity concerns only products sold by DESFA on the Greek side of the IP. 

237 Source: RBP Booking Platform monthly reports 

238 Booked capacity beyond the IP side’s technical capacity relates to interruptible capacity sold. 

239 Source: DESFA 

 
 
 
 
Figure 49: Number of days with high and low utilization at Kulata (BG) / Sidirokastron (GR) IP240 

(a) DESFA entry 

(b) Bulgartransgaz exit 

CMPs  were  applied  to  release  firm  capacity  only  at  the  Greek  entry  of  the  IP,  with  DESFA  offering 
additional  firm  capacity  through  oversubscription.  The  oversubscribed  capacity  was  auctioned  as 
unbundled, as Bulgartransgaz did not make any additional capacity available at the exit of the IP. The 
average amount of additional capacity  made available by DESFA was similar each of the examined gas 
years (Figure 50). 

Figure 50: Average241 amount of capacity released at Kulata (BG) / Sidirokastron (GR) IP through 
CMPs242 

DESFA made most additional capacity available in 2022 and early 2024 (Figure 51). Between April 2022 
and March 2024, additional capacity was offered on 689 days, i.e. around 95% of the time. During this 
period, the firm capacity offered by the TSO was increased by up to a maximum of 11% of the IP side’s 
technical capacity. On most days that additional firm capacity was auctioned, it was fully booked. 

240 Source: DESFA, Bulgartransgaz 

241 The average capacity is estimated only for the days on which capacity was released through CMPs. 

242 Source: DESFA 

 
 
 
 
 
 
 
Figure 51: Offering of additional capacity through oversubscription at Greek entry 243 

Additional firm capacity was offered even on days that the daily nominations by the network users were 
high (Figure 52). Nevertheless, DESFA did not activate its buy-back mechanism, as not all firm capacity 
sold  had  to  be  used  on  any  given  day  by  the  network  users,  and  technical  restrictions  could  be 
accommodated  by  the  TSO  with  interruption  of  booked  interruptible  capacity.  Consequently,  the 
capacity  released  through  oversubscription  facilitated  addressing  short-term  congestion,  when 
utilization at the IP side was limited, without leading to additional costs for the TSO to buy back firm 
capacity from the network users. 

Figure 52: Daily nominations and offering of additional capacity at Greek entry 244 

Key findings 

  All capacity has been booked at both Bulgarian exit and Greek entry 

 

The IP was contractually congested. On the Greek side there was unmet demand for 
yearly and quarterly unbundled firm capacity 

  DESFA offered additional capacity through oversubscription, most of which was fully 

booked by network users 

243 Source: DESFA 

244 Source: DESFA 

 
 
 
 
 
  Even on days with high daily nominations, DESFA did not have to buy back the 

additional capacity sold. Physical constraints were met by interrupting interruptible 
capacity 

VIP BENE (Belgium to the Netherlands 
direction) 

to 

to 

transport  gas 

from  Belgium 

During the energy crisis VIP BENE was used up to its full 
capacity 
the 
Netherlands. Since March 2022 at least 87% of the VIP’s 
technical capacity has been booked, and during the period 
between March 2022 and May 2023 firm capacity was sold 
out  65%  of  the time  (299  days).  Utilization  of the  point 
was also very high during the same period (Figure 53). At 
the  Belgian  exit,  physical  congestion  was  observed  on 
over 200 days, corresponding to around 45% of the time.   

Figure 53: Use of capacity at VIP BENE245 

(a) Fluxys exit 

(b) GTS entry 

As a result of the high utilization at the network point, demand for firm capacity was very large in 2022 
and 2023. Many auctions for firm yearly and quarterly products during that period resulted in unmet 
requests  for  capacity  and  auction  premia  (Table  34).  During  the  2022  auctions,  demand  for  2023 
quarterly products reached more than 7 times the bundled firm capacity offered by the TSOs. Demand 

245 Source: Fluxys, ENTSOG TP 

 
 
 
 
 
for monthly and daily capacity was also very high, with network users requesting more capacity than 
offered by the TSOs at most auctions until the end of 2022. 

Table 34: Results of capacity auctions for yearly and quarterly bundled and unbundled capacity246 

Product 

No. of 
rounds 

No of 
participants 

No of 
contracts 

Unmet 
demand 

Auction 
timing 

Bundled capacity 

Jul 2022 

May 2022 

Aug 2022 

Nov 2022 

Feb 2023 

May 2023 

Yearly firm (GY 2022/23) 
Yearly firm (GY 2023/24) 
Quarterly firm (Q3-22) 
Quarterly firm (Q1-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q1-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q3-23) 

Yearly firm (GY 2023/24) 

Jun 2023 
Unbundled capacity – Belgian side 
Jul 2023 
Unbundled capacity – Dutch side 
Jul 2022 

Yearly firm (GY 2023/24) 

Yearly firm (GY 2023/24) 

24 
6 
12 
45 
12 
12 
5 
14 
14 
4 
4 
8 

14 

3 

8 

32 
18 
28 
18 
26 
26 
13 
26 
25 
6 
6 
8 

19 

2 

2 

40 
30 
34 
10 
14 
14 
4 
4 
4 
0 
0 
2 

4 

2 

2 

403 GWh/d 
91 GWh/d 
685 GWh/d 
181 GWh/d 
390 GWh/d 
387 GWh/d 
17 GWh/d 
161 GWh/d 
158 GWh/d 
1.2 GWh/d 
1.2 GWh/d 
1.6 GWh/d 

64 GWh/d 

2.9 GWh/d 

7 GWh/d 

Interest for interruptible capacity was also high in the second half of 2022. On the Dutch side of the 
VIP, no restrictions applied to the amount of interruptible capacity that could be sold, resulting in cases 
where the booked interruptible capacity was over 50 times higher than the technical capacity of the 
point (Figure 54). The amount of interruptible capacity that was booked at the Belgian exit point was 
much lower (including over-nominations for within day interruptible capacity). 

Figure 54: Booking of interruptible capacity at VIP BENE247 

(a) Fluxys exit 

246 Source: PRISMA monthly reports 

247 Source: Fluxys, ENTSOG TP 

 
 
 
 
(b) GTS entry 

Figure 55: Number of days with high and low utilization at VIP BENE248 

(a) Fluxys exit 

(b) GTS entry 

As shown in Figure 55, for many days in gas years 2021/22 and 2022/23, both sides of the network 
point were fully utilized. Cases of low utilization when capacity was fully booked were very limited at 
the Belgian side of the VIP249. With such a profile of capacity use the Belgian side of the point can be 
considered as physically, and not contractually, congested for most of 2022 and 2023. 

An oversubscription and buy-back scheme applies at the Dutch side of the network point, allowing the 
TSO to offer additional capacity to the network users. Gasunie started offering additional capacity at 
the VIP in June 2023. The average amount of capacity made available each gas year is presented in 
the figure below.  

248 Source: Fluxys, ENTSOG TP 

249 ENTSOG data indicate that, at the Dutch side ,capacity was fully booked from May to September 2023, while at the Belgian side 

the Fluxys data show that 96% of the capacity was booked for most days of that period. There is therefore a difference in the 
number of days with booked but unused capacity for gas year 2022/23. 

 
 
 
 
 
 
 
Figure 56: Average250 amount of capacity released at VIP BENE – Dutch entry through CMPs 251 

Additional capacity was offered by Gasunie on 59 days in gas year 2022/23 (starting in June 2023) and 
215 days in gas year 2023/24. The amount of additional capacity offered ranged from 5% to 25% of 
the point’s technical capacity. When capacity was offered in June and July 2023, all firm capacity sold 
out and part of the additional capacity was also booked. The figure below provides an overview of the 
offered  and  booked  additional  capacity.  Although  network  users  were  interested  in  contracting 
oversubscribed capacity, this corresponded to around just 1.5% of the point’s technical capacity. 

Figure 57: Offering of additional capacity through oversubscription at VIP BENE – Dutch entry252 

Additional firm capacity was offered even on days that the daily nominations by the network users were 
high (Figure 58). There were days in June 2023 when the TSO offered to the primary market additional 
capacity corresponding to almost 20% of the technical capacity, even though the initial nominations 
submitted by network users corresponded to 70% to 80% of the point’s throughput. 

250 The average capacity is estimated only for the days on which capacity was released through CMPs. 

251 Source: ENTSOG TP 

252 Source: ENTSOG TP 

 
 
 
 
 
Figure 58: Daily nominations and offering of additional capacity at VIP BENE Dutch entry253 

At the Belgian side of the VIP no CMPs were activated. Instead, the TSO relied on market measures, 
and especially over-nomination, to increase the use of the network when firm capacity was fully booked. 
The over-nominations for interruptible capacity was triggered only for those days that all firm capacity 
had already been contracted. 

Different mechanisms were applied to increase the use of capacity at the two sides of the VIP, which 
could have created constraints in the harmonized use of capacity. However, the actual use of additional 
capacity at the Dutch side of the network point was limited only to a small period of time (June-July 
2023) and with booked capacity not exceeding 1.5% of the point’s technical capacity. It can therefore 
be  expected  that  the  use  of  different  mechanisms  has  not  created  considerable  challenges  for  the 
operation of the VIP.  

Key findings 

  Capacity at VIP BENE was highly booked and used during the energy crisis, especially 
during the period between March 2022 and May 2023. Requests by network users for 
firm capacity could not be addressed during that period. 

 

In gas years 2021/22 and 2022/23, both sides of the network point were physically 
congested on multiple days. On the other hand, situations where capacity was booked 
but unused did not occur often, especially on the Belgian side of the point. 

  An OS+BB mechanism applies at the Duch side of the VIP. Gasunie started offering 

additional capacity in June 2023. So far, the network users booked such capacity only in 
June and July 2023, and in small amounts, not exceeding 1.5% of the point’s 
throughout. 

  At the Belgian side of the network point, instead of CMPs, the TSO relies on over-

nominations to increase the utilization of booked but unused capacity.   

  Due to the limited use of additional capacity on the Dutch side of the VIP, it can be 

expected that the application of different mechanisms has a limited impact on the use of 
capacity. 

253 Source: DESFA 

 
 
 
 
VIP Pirineos (Spain to France direction) 

From  March  2022  and  until  the  examined  period 
(September 2024), capacity bookings at VIP Pirineos in the 
direction from Spain to France have regularly remained at 
very high levels. During this period, firm capacity at the VIP 
was sold out for 433 days on the Spanish side (43% of the 
time) and 406 days on the French side (40% of the time). 
During  the  same  period,  utilization  of  capacity  at  the  VIP 
did  not  follow  the  very  high  booking  rates  (Figure  59). 
Capacity was fully utilized (indicating physical congestion) 
on both sides only on 35 days, most of which in April and 
May 2023.  

Figure 59: Use of capacity254 at VIP Pirineos, Spain to France direction255 

(a) Enagás exit 

(b) Teréga entry 

Due to the high level of capacity booking the VIP, and the limited utilization most of the time, there 
was also interest for interruptible capacity (Figure 60). 

254 Booked capacity beyond the IP side’s technical capacity relates to interruptible capacity sold. 

255 Source: ENTSOG TP 

 
 
 
 
 
 Figure 60: Booking of interruptible capacity at VIP Pirineos, Spain to France direction256 

(a) Enagás exit 

(b) Teréga entry 

Demand for firm capacity exceeded the amount of capacity offered by the TSOs in several auctions for 
yearly, quarterly and monthly products. Notably, during the November 2022 auctions, demand for some 
2023 quarterly products reached almost 10 times the bundled firm capacity offered by the TSOs. The 
table below outlines the auction results for yearly and quarterly capacity during the examination period.  
Unfulfilled requests for monthly capacity occurred in several months, with the most notable cases being 
the bundled products of May and June 2022, when demand for capacity was 2.5 and 5 times higher 
than the offered amount, respectively. Unmet demand for capacity was also observed in auctions for 
daily firm capacity (for bundled capacity as well as for unbundled capacity on the Spanish side). 

Table 35: Results of capacity auctions for yearly and quarterly bundled and unbundled capacity257 

Auction 
timing 

Bundled capacity 

Jul 2022 

May 2022 

Aug 2022 

Nov 2022 

Product 

No. of 
rounds 

No of 
participants 

No of 
contracts 

Unmet 
demand 

Yearly firm (GY 2022/23) 

Quarterly firm (Q3-22) 
Quarterly firm (Q4-22) 
Quarterly firm (Q1-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 

11 

33 
8 
11 
15 
15 

9 

5 
5 
7 
19 
19 

12 

10 
6 
8 
12 
12 

22 GWh/d 

12 GWh/d 
4 GWh/d 
12 GWh/d 
167 GWh/d 
167 GWh/d 

256 Source: ENTSOG TP 

257 Source: PRISMA monthly reports 

 
 
 
 
 
Feb 2023 

May 2023 

Nov 2023 

Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q2-24) 
Quarterly firm (Q3-24) 
Yearly firm (GY 2023/24) 

Jun 2023 
Unbundled capacity – Spanish side 
May 2022 

Quarterly firm (Q3-22) 

Nov 2022 
Unbundled capacity – French side 

Quarterly firm (Q1-23) 

Nov 2022 

Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 

12 
9 
5 
9 
11 
12 

5 

11 

27 
27 

10 
11 
4 
7 
6 
19 

3 

4 

2 
2 

2 
2 
2 
6 
8 
28 

3 

4 

2 
2 

11 GWh/d 
12 GWh/d 
1 GWh/d 
13 GWh/d 
16GWh/d 
142 GWh/d 

17 GWh/d 

20 GWh/d 

3 GWh/d 
3 GWh/d 

As shown in the figure below, capacity was fully booked but underutilized at both sides of the VIP on 
several days in each examined gas year. On all these days, there were also unsuccessful requests from 
market participants to buy firm capacity, indicating that the point was contractually congested.  

Figure 61: Number of days with high and low utilization at VIP Pirineos 258 

(a) Enagás exit 

(b) Teréga entry 

Enagás  and  Teréga  have  established  a  common  mechanism  for  the  application  of  the  OS+BB 
mechanism at the VIP. The same methodology applies to determine the additional capacity to be made 
available each day, allowing the TSOs to offer bundled additional capacity. As a result, the amount of 
capacity offered in each gas year was almost the same (Figure 62). No other CMP has been activated 
at the network point. 

258 Source: ENTSOG TP 

 
 
 
 
 
 
Figure 62: Average259 amount of capacity released at VIP Pirineos through CMPs260 

(a) Enagás exit 

(b) Teréga entry 

During the examination period, the TSOs offered on several days additional capacity up to a maximum 
of 22.5 GWh/d. i.e. up to 10% of the VIP’s technical capacity. Although additional capacity was offered 
during all 3 examined gas years, booking of capacity has been very limited.   

The methodology applied by the TSOs to determine the amount of additional capacity offered (if any) 
resulted  in  the  mechanism  being  triggered  on  days  that  nominations  were  low,  and  thus  the  risk  of 
buying back capacity was limited. This is evident in the figure below; for example, no additional capacity 
was made available in April – June 2022 and 2023, when nominated volumes by network users were 
high.   

Figure 63: Daily nominations and offering of additional capacity at VIP Pirineos261 

(a) Enagás exit 

259 The average capacity is estimated only for the days on which capacity was released through CMPs. 

260 Source: ENTSOG TP 

261 Source: ENTSOG TP 

 
 
 
 
 
 
 
(b) Teréga entry 

On the French side of the VIP, the UBI mechanism was also triggered when capacity booked exceeded 
98%. During the period from 01/09/2022 to 31/12/2024, UBI was offered by Teréga on 44% of days. 
The volumes reallocated represented about 4% of total allocated volumes over the period262.  

Key findings 

•  Most firm capacity at VIP Pirineos, in the Spain to France direction, was booked, 

including multiple days on which capacity was fully sold out. Many days in this period, 
however utilization of capacity remained low. 

•  Unmet demand for firm capacity was observed throughout the examined period, 

resulting in contractual congestion. Most days with utilization below 80% were observed 
in gas year 2022/23. 

•  Enagás and Teréga apply the OS+BB mechanism using a common mechanism and offer 

bundled additional capacity through oversubscription.  

•  Additional capacity is made available if nominations are low. The interest of the users for 

this capacity has been limited. 

•  Application of UBI on the French side was efficient. It resulted in more capacity 

reallocated than the OS+BB mechanism. 

262 Source: CRE 

 
 
 
 
VIP TTF-THE-H (Netherlands to 
Germany direction) 

The VIP began its operation in April 2022, after 
two existing VIPs from the German side (VIP-
TTF-NCG-H and VIP-TTF-GASPOOL-H) merged 
into  a  single  point.  Most  capacity  on  the 
German side of the VIP has been booked since 
October  2022,  including  periods  when  all 
capacity  was  booked  (Figure  64).  This  high 
booking  of  capacity  is  associated  with  the 
changes  in  the  technical  capacity  of  the  VIP 
reported by GUD, which at periods decreased 
from around 660 GWh/d to 450 GWh/d. On the Dutch side of the VIP, capacity booking was increased 
only between early October and mid-November 2022, when firm capacity was even sold out for a few 
days. 

Figure 64: Use of capacity263 at VIP TTF-THE-H264 

(a) GTS exit 

(b) GUD entry 

With  firm  capacity  being  fully  booked  on  the  German  side  of  the  VIP,  there  was  also  interest  for 
interruptible  capacity  (Figure  65).  Most  interest  for  booking  interruptible  capacity  was  observed  in 

263 Booked capacity beyond the IP side’s technical capacity relates to interruptible capacity sold. 

264 Source: ENTSOG TP, GUD 

 
 
 
 
 
Octover and November 2022, when firm capacity on the Dutch side of the point was also almost fully 
booked. 

 Figure 65: Booking of interruptible capacity on the German side of the VIP265 

Demand for firm capacity at the VIP was very large in 2022 and 2023. As a result, bundled firm capacity 
was sold out in auctions for yearly and quarterly products (Table 36). Especially the yearly auctions in 
July 2022 resulted in very high levels of unmet demand for the next gas years. Interest for monthly 
and daily capacity was also high, leading to auction premia, for products with runtime between October 
and December 2022.   

Table 36: Results of capacity auctions for yearly and quarterly bundled and unbundled capacity266 

Auction 
timing 

Bundled capacity 

Jul 2022 

May 2022 

Aug 2022 

Nov 2022 

Aug 2023 

Jun 2023 

Product 

No. of 
rounds 

No of 
participants 

No of 
contracts 

Unmet 
demand 

Yearly firm (GY 2022/23) 
Yearly firm (GY 2023/24) 
Quarterly firm (Q3-22) 
Quarterly firm (Q1-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q1-23) 
Quarterly firm (Q2-23) 
Quarterly firm (Q3-23) 
Quarterly firm (Q2-24) 
Yearly firm (GY 2023/24) 
Yearly firm (GY 2024/25) 

29 
28 
51 
15 
12 
8 
4 
15 
16 
5 
7 
22 

59 
32 
28 
28 
24 
23 
12 
19 
19 
7 
19 
13 

70 
48 
42 
32 
28 
34 
12 
14 
12 
12 
30 
10 

650 
309 
199 
      146  

98 
54  
115  
25  
74  
15 
65 
68 

As shown in the figure below, capacity of the German side was fully utilized for several days in gas year 
2022/23. In gas year 2023/24, however, capacity was fully booked but underutilized. This was observed 
during  the  period  from  July  –  September  2024,  when  the  technical  capacity  reported  by  GUD  was 
decreased  to  400  GWh/d.  On  the  Dutch  side,  where  the  technical  capacity  reported  by  the  TSO  is 
higher, capacity was fully booked only on 3 consecutive days in October 2022 and one day in 1 day in 
September 2023. 

265 Source: ENTSOG TP, GUD 

266 Source: PRISMA monthly reports 

 
 
 
 
Figure 66: Number of days with high and low utilization at VIP TTF-THE-E – German entry267 

The figure below provides an overview of the average daily capacity released through CMPs at both 
sides of the VIP. On the Dutch side, GTS offered a large amount of capacity through oversubscription, 
corresponding to 41% of the technical capacity in gas year 2021/22 and 20% in gas year 2022/23. On 
the German side, the FDA UIOLI mechanism was applied (the mechanism applies at all Austrian IPs 
regardless  of  their  congestion  status),  resulting  to  the  release  of  capacity  when  the  renomination 
restrictions were activated.  

Figure 67: Average268 amount of capacity released at VIP TTF-THE-H through CMPs 269 

(a) GTS exit 

(b) GUD entry 

It appears that the additional capacity offered by GTS was booked by network users only on the very 
few days in October 2022, when all firm capacity was sold. Utilization of the VIP side during these days 
was below 90%, and there was thus no need for buying back capacity. 

On the German side, during the examined period, the FDA UIOLI mechanism was activated most days 
of each gas year (155 days in gas year 2021/22 out of the 183 day of the VIP’s operation, 362 days in 
gas year 2022/23 and 309 days in gas year 2023/24). The amount of capacity released was much lower 

267 Source: GUD 

268 The average capacity is estimated only for the days on which capacity was released through CMPs. 

269 Source: GUD 

 
 
 
 
 
 
 
than  the unused part  of the network  point  (Figure 68),  it  can  therefore  be  expected that  it  was  not 
necessary to reallocate released capacity to other network users. 

Figure 68: Capacity released through FDA UIOLI at VIP TTF-THE-H – German entry 270 

Different CMPs apply at the two sides of the VIP, which may potentially hamper the use of capacity. It 
can be expected, however, that due to the very limited demand additional capacity on the Dutch side, 
the renomination restrictions imposed by the FDA UIOLI are not resulting in considerable challenges 
for the operation of the VIP. 

Key findings 

•  Most technical capacity on the German side of the VIP has been booked for prolonged 

periods of time since October 2022. The technical capacity reported on the Dutch side is 
larger and booking was high only in the 4th quarter of 2022. 

• 

The German side of the VIP was physically congested for several days in gas year 
2022/23. In gas year 2023/24 congestion has been contractual (may also result from 
the decrease of the reported technical capacity). 

•  An OS+BB mechanism applies at the Dutch side of the VIP. However, it appears that 

additional capacity was only booked on a few days in October 2022. 

•  An FDA UIOLI mechanism applies on the German side of the VIP. Capacity has been 

released on most days over the past 3 gas years, however utilization does not appear to 
have been high enough to result in reallocation of the released capacity. 

•  Due to the very limited use of additional capacity on the Dutch side of the VIP, it can be 
expected that the application of different CMPs has not impacted the use of capacity. 

270 Source: GCA, TAG 

 
 
 
 
Swinoujscie LNG terminal 

The  capacity  at  the  Swinoujscie  LNG 
terminal  has  already  been  contracted  by  a 
single terminal user, PKN Orlen under open 
season procedures conducted in the past271. 
terminal’s 
In  2009–2010  all  of 
regasification capacity at the time (370,000 
m3/hr) was booked during the first allocation 
process.  Capacity  expanded  to  570,000 
m3/hr  in  2017.  Through  a  second  open 
season,  conducted  in  2020,  all  of  the 
terminal’s 
planned 
regasification capacity was also allocated to PKN Orlen. 

existing 

and 

the 

Utilization of the booked regasification capacity has been very high throughout the examined period 
(Figure  69).  In  gas  year  2021/22  average  daily  utilization  was  73%,  increasing  to  86%  in  gas  year 
2022/23  and  remaining  at  high  levels,  83%,  in  gas year  2023/24.  The  utilization exceeded  90%  on 
many days each year, with the highest being on 214 days (58% of the time) in 2022/23. The capacity 
utilization  trends  indicates  that  there  was  no  booked  but  unused  capacity,  maximizing  the  available 
technical capabilities of the facility.  

Figure 69: Use of capacity at Swinoujscie LNG terminal272 

271 In November 2022, PKN Orlen completed its merger with the Polish incumbent gas supplier, Polish Oil and Gas Company (PGNiG), 

which had contracted the regasification capacity at the terminal. 

272 Source: Gaz System 

 
 
 
 
 
 
 
Annex IV: Survey on the impact of decarbonisation on the 
gas system 

The survey targeted TSOs, NRAs,  Energy Agencies and network users. It focused exclusively on the 
management of congestion at the gas systems. The dedicated hydrogen systems273 were not examined 
within the scope of the survey. The survey was structured into three sections with a total of 23 brief 
questions, first asking questions related to gas demand, then focusing on the network related changes 
and lastly targeting CMPs. The survey was launched on February 12, 2025, and closed on March 14, 
2025. The findings are based on 23 responses and are discussed below. 

From  the  respondents  12  came  from  TSOs,  8  came  from  NRAs  and  3  came  from  Energy  Agencies. 
Stakeholders  who  have  answered  are  from  France,  Croatia,  Slovenia,  Germany,  Italy,  Hungary,  the 
Netherlands, Poland, Luxemburg, Czech Republic, Finland, Portugal, Spain and Greece. 

The  findings  of  the  survey  concern  different  focus  areas.  The  following  sections  describe  general 
findings, CMP focused findings, infrastructure planning related insights, and finally information about 
hydrogen, blending and biomethane. 

General findings 

The  survey  included  questions to  gain  insights  on  the  general  trends  of  the  sector.  These  questions 
concern the future natural gas demand, the composition of gas, and the development of the natural 
gas system. 65% of the respondents stated that the aggregated natural gas demand will decline slightly 
until 2040 as a result of the decarbonization of the sector (Figure 70) while expecting a greater reliance 
on renewable and low-carbon gases and decreasing fossil gas demand (Figure 71). The lower demand 
in the future originates from higher electrification (for example heating and industry), larger renewable 
energy resources, and a shift towards hydrogen as a low-carbon gas. Respondents also underlined that 
in the short and medium term, the natural gas system cannot be decommissioned due to security of 
supply aspects and the current phase out of coal. 

The future demand is expected to be met through a combination of blended hydrogen, biomethane, 
and fossil gas, with the proportions varying by region. Biomethane is expected to play a significant role 
in most operational areas, though largely connected to distribution systems at the moment. Blended 
hydrogen  is  seen  as  a  potential option,  but  its  exact  role  remains  uncertain  as  it  is  still  in  the early 
stages of development and the coming will be decisive. There is no clear perspective on whether and 
how gas flows across the European natural gas system will be impacted: 22% of respondents expect 
changes, 39% do not, and 35% indicate that there is uncertainty around it with geopolitical situations 
and the role of biomass driving the development of changes in flow. The demand will largely center 
around the same locations as today. 

273 A system of infrastructure, including hydrogen networks, hydrogen storage and hydrogen terminals, which contains hydrogen of 

a high grade of purity. 

 
 
 
Figure 70: Answers to the question how demand for natural gas (fossil gas, biomethane, blended 
hydrogen) will develop during the decarbonization 

Figure 71: Answers to the question about an expected decline in fossil gas demand until 2040 

CMP measures 

Most of the respondents (83%) do not expect there to be an increased congestion in their natural gas 
system due to capacity reductions following the decommissioning of infrastructure. Several respondents 
stated that a decommissioning will not take place if it can potentially impact the congestion. 

When asked if the respondents will be able to respond with the current CMP mechanisms to the changing 
gas flows, 35% said yes, 17% said they are unsure if they can respond, 13% said no and 13% said 
they will be able to respond with some of the CMP mechanisms. The respondents that said they are 
unsure,  stated  that  the  change  in  flows  is  not  certain  and  that  some  minor  changes  to  the  CMP 
mechanisms  might  be  necessary.  The  respondents  who  said  no,  elaborated  that  the  current  CMP 
mechanisms  deal  with  contractual  congestion,  but  there  may  be  more  physical  congestion  moving 
forward. 

When  asked if  the  changes  in  gas  flow  patterns due  to  blended  hydrogen  and/or  biomethane  would 
require changes in the management of cross-border flows 52% said no. While several answered that 
they are unable to answer due to the lack of information on how/if the flow patterns will change. 

Overall, the respondents do not think there is a need for changing the CMP mechanisms following the 
decarbonization of the natural gas sector. 

 
 
 
 
Figure 72: Answers for whether the current CMP mechanisms are supportive to respond to changing 
gas flows 

Planning 

As  mentioned  above,  some  respondents  expect  that  there  will  be  changes  in  flows  due  to 
decarbonization. For most respondents it is at this stage not possible to anticipate flow patterns. Some 
say that the flow patterns are influenced by neighboring countries and their decarbonization strategy. 
In this regard, flows from distribution networks to transmission networks may change, even seasonally. 
The underlying uncertainty and development under decarbonization can influence planning. 

A total of 48% of the respondents said that the uncertainty in the natural gas demand impacts their 
long-term planning to a mid or high extent. Furthermore, 69% of the respondents responded that this 
impact comes from the reduction in natural gas demand, and 31% said that it comes from a changed 
cross-border trade.  

The  respondents’  answers  to  the  question  of  whether  they  are  repurposing  parts  of  the  natural  gas 
network to accommodate hydrogen were mixed. Some have already started the repurposing, and the 
percentage  share  of  repurposing  is  around  10-30%,  while  some  are  uncertain  about  the  future 
development of their assets. 

Gas mix and blending 

The  role  of  blended  hydrogen  in  the  future  is  uncertain  according  to  the  respondents:  30%  of 
respondents said that blended hydrogen will have an increased role in their operation area, 17% said 
it will not, 43% said other and 9% of the respondents skipped the question. Multiple responders say 
that the future role of blended hydrogen in not clear yet, and that this will not start until about 10 years 
in  the  future.  Others  responded  that  hydrogen  will  be  transported  in  dedicated  pipelines  and  will 
therefore not be blended. A possible injection of blended hydrogen into the natural gas network is not 
expected to change flow directions (significantly). 

As for biomethane, 65% of the respondents said that it will have an increased role in their operations 
area in the future, while 9% said it will not, and 26% responded “other”. The respondents commented 
that biomethane will likely remain dominantly affecting the distribution network. However, there are 
indications that the infeed of biomethane will reverse the flows in the system to go from distribution 
networks to transmission networks and might require adjustments to accommodate the reversed flows. 
The  reversed  flows  come  as  the  production  from  biomethane  plants  could  surpass  the  local 
consumption, in particular in summer months, and therefore the injection into the transmission system 
is needed. 

 
 
 
Annex V: Survey on implementation of CMPs 

The survey targeted TSOs, NRAs, and energy traders. Its aim was to collect the views, feedback and 
input from key stakeholders of the gas industry, concerning the design and application of CMPs, focusing 
on  the  identified  challenges  and  interventions,  examining  their  relevance,  importance  and  expected 
impact. The survey was structured into 6 main sections, most focusing on different areas of interest 
relating to the application of CMPs: 

•  Booking of capacity 
•  Definition of congestion and scope of CMP Guidelines 
• 
Establishment of CMPs 
• 
Effectiveness and efficiency of CMPs 
•  Cross-border harmonization of CMPs 
• 

Transparency of information relating to CMPs 

The survey was launched on April 14, 2025, and closed on May 9, 2025. The findings are based on 30 
responses and are gathered below and follow the structure of the survey. From the respondents, 22 
are  TSOs,  5  are  NRAs  and  3  are  energy  traders.  Stakeholders  from  the  following  Member  States 
provided responses: Austria, Belgium, Croatia, Czech Republic, Denmark, France, Germany, Greece, 
Hungary, Ireland, Italy, Lithuania, Poland, Slovakia, Slovenia, Spain. 

An overview of the responses provided by the stakeholders is provided below274. 

Booking of capacity 

The  questions  in  this  section  of  the  survey  aimed  at  collecting  inputs  relating  to  the  trends  for  the 
contracting of capacity, including the existence of legacy contracts and their impact of congestion, the 
preference for long or short-term capacity booking and the impact of the energy crisis to the use of 
short-term capacity.  

Respondents  to  the  survey  have  indicated  that  legacy  contracts  are  still  in  place  in  several  Member 
States (Figure 73). Based on the answers of the stakeholders, the actual impact of these contracts on 
contractual congestion at the IPs where they apply varies between the different Member States (Figure 
74). Nevertheless, none of the stakeholders responded that legacy contracts have a significant impact 
on congestion. 

Figure 73: Answers to the question about the existence of legacy contracts in their gas system 

274 Percentages of responses refer to the number of stakeholders that provided a response to the particular question. Responses of 

“No response / Not applicable” are not accounted for. 

 
 
 
 
Figure 74: Answers to the question about the impact of legacy contracts on congestion 

The preference shown by network users to book yearly, quarterly or monthly and shorter-term products 
varies. As shown in Figure 75, in several Member States network users prefer to contract long-term 
capacity, while in others short-term capacity is mostly used. The respondents indicated that the trends 
in using capacity have changed, even slightly, in most Member States after the energy crisis. 

Figure 75: Answer to the questions about the duration of preferred capacity products and the changes 
to the preferences post crisis 

Definition of congestion and scope of CMP Guidelines 

The questions in this section of the survey focused on the sufficiency of the existing criteria to identify 
contractually congested network points, the importance of CMPs in the case of IPs with virtual reverse 
flow and the relevance of the Guidelines to applying congestion measures at LNG terminals. 

Most  stakeholders  (69%)  consider  that  the  most  appropriate  definition  for  contractual  congestion 
should include fully booked points with underutilized capacity and demand from other network users, 

 
 
 
 
while another 24% considers the existing definition as sufficient (Figure 76). Only 1 stakeholder (NRA) 
did not respond to the question. 

Figure 76: Answers to the question about the definition of contractually congested points 

Firm capacity is fully booked, the point is
underutilized and there is interest from other  users
to book capacity

Firm capacity is fully booked and the point is
underutilized

7%

(2)

Demand for firm capacity exceeds that offered by
the TSO at capacity auctions

24%

(7)

69%

(20)

Other

0%

(0)

0%

20%

40%

60%

80%

100%

A  small  percentage  of  the  respondents  (19%)  considers  that  the  existing  criterion  included  in  the 
Guidelines for identifying congested IP sides due to non-offering of capacity is sufficient (Figure 77). 
10 stakeholders (39%) expressly answered that the reasons for non-offer should be examined before 
tagging a point as contractually congested. Out of the 11 “other” responses, based on the elaboration 
provided, 10 (another 39%) are practically in favour of assessing the reason for congestion. It has also 
been  noted  by  respondents  that  ACER  should  consider  the  reasons  for  capacity  non-offer  in  its 
Congestion  Reports,  and  that  the  NRAs  should  have  the  possibility  to  investigate  the  reasons  why 
capacity was not offered. In total 4 stakeholders (2 NRAs, 2 TSOs) did not respond to the question. 

Figure 77: Answers to the question about congestion in case of non-offer of capacity products 

The criterion is sufficient as is

19%

(5)

The criterion should examine the reasons for
which capacity was not offered

38%

(10)

Other

42%

(11)

0%

20%

40%

60%

80%

100%

Concerning  the  scope  of  the  CMPs,  most  respondents  (78%)  indicate  that  the  scope  of  contractual 
congestion covers only physical flows and does not include IPs with virtual reverse flows (Figure 78). 
Furthermore,  almost  half  of  the  respondents  (53%)  answered  that  the  CMP  guidelines  should  not 
include any guidelines for LNG terminals, stressing that the operation of LNG terminals and pipelines 

 
 
 
 
 
 
are different (Figure 79). 15% of the responses were in favour of the Guidelines setting, either detailed 
or high-level, requirements for congestion management. 3 of the “other” responses implicitly supported 
this view, elaborating the need for a framework to manage congestion at the terminals. 

Figure 78: Answers to the question about including VRF IPs in the scope of the CMP Guidelines 

Network points’ sides with either physical or virtual 
flows

22%

(5)

Only network points’ sides with physical flows

78%

(18)

0%

20%

40%

60%

80%

100%

Figure 79: Answers to the question about including LNG terminals in the scope of the CMP Guidelines 

Yes – The CMP GL should set a high-level 
requirement for operators of LNG terminals for 
congestion management measures

5%

(1)

Yes – The CMP GL should define specific congestion 
management procedures to be applied at LNG 
terminals

11%

(2)

No – the CMP GL should not include congestion 
management measures at LNG terminals

53%

(10)

Other

32%

(6)

0%

20%

40%

60%

80% 100%

When asked to rate the importance of specific measures in managing congestion at LNG terminals, one 
third of the stakeholders responded. Most respondents consider that the most important measures are 
those activated on the initiative of the terminal users (Figure 80), i.e. the trading of capacity at the 
secondary market (most preferred option) and the surrender of capacity. Offering short-term products 
by the operator is considered of less importance. The activation of a UIOLI mechanism is considered 
very important or important by 6 respondents but not important at all or with limited importance or of 
no importance at all by the remaining 4.  

 
 
 
 
 
 
Figure 80: Answers to the question about rating the measures for managing congestion at terminals 275 

Establishment of CMPs 

The  questions  in  this  section  of  the  survey  focused  on  the  preferred  types  of  measures  to  manage 
congestion, the role of the NRAs in promoting market-based measures and their complementarity with 
CMPs, the trigger for activating the FDA UIOLI mechanism and the possible establishment of a mid-
term UIOLI mechanism. 

The  majority  of  stakeholders  consider  the  use  of  market-based  measures  as  most  appropriate  to 
manage  contractual  congestion  (Figure  81).  Offering  of  interruptible  capacity  is  the  most  prominent 
solution  indicated,  followed  by  the  secondary  capacity  market  and  over-nomination.  FDA  UIOLI  and 
surrender of capacity are considered as the most preferred CMPs. 

Figure 81: Answers to the question about rating the measures managing congestion275 

275 Rating from 1 – 4 with 1 indicating low importance and 4 very strong importance. Average from all responses (except N/A) are 

presented. 

 
 
 
 
 
Most  of  the  respondents  (62%)  are  in  favour  of  the  NRAs  being  required  to  promote  market-based 
measures (Figure 82). In their responses several stakeholders stressed the importance and efficiency 
of market measures. Several of the negative responses indicated that the NRAs should specify targeted 
measures. 4 stakeholders (1 NRA, 3 TSOs) did not respond to the question. Furthermore, the majority 
of stakeholders (59%) consider that that a combination of market measures and CMPs (OS+BB or FDA 
UIOLI) is necessary to address short-term congestion, while the 2 “other” responses highlight the need 
to combine market measures with CMPs (Figure 83). Only 4 respondents consider that application only 
of CMPs is sufficient for managing congestion. 3 stakeholders (1 NRA, 2 TSOs) did not respond to the 
question. 

Figure 82: Answers to the question on NRAs being required to promote market-based measures 

Yes

No

62%

(16)

38%

(10)

0%

20%

40%

60%

80%

100%

Figure 83: Answers to the question about the complementarity of market-based measures and CMPs 

The application of an OS+BB or FDA UIOLI
mechanism is sufficient to manage short-term
contractual congestion

The application of only market measures is
sufficient to manage  short-term contractual
congestion

A combination of market measures and an
OS+BB or FDA UIOLI mechanism is necessary
to manage  short-term contractual congestion

15%

(4)

19%

(5)

59%

(16)

Other

7%

(2)

0%

20%

40%

60%

80% 100%

Several  responses  (41%) indicate  that  the  NRAs  should  decide  on  the  activation  of  FDA  UIOLI.  The 
“other”  responses  (44%)  elaborated  answers  such  as  that  there  can  be  a  benefit  if  the  mechanism 
applies at all IPs, ACER’s reports cannot by themselves lead to activation of the FDA UIOLI, and that 
the final decision should be taken by the NRA. 3 stakeholders (1 NRA, 2 TSOs) did not respond to the 
question. 

 
 
 
 
 
 
Figure 84: Answers to the question about the activation of the FDA UIOLI mechanism 

Yes – The application of the FDA UIOLI mechanism 
should be linked to the outcomes of ACER’s Report

15%

(4)

No – The NRAs should decide ad hoc on the 
application of the FDA UIOLI mechanism depending 
on the situation at the network point on that time

41%

(11)

Other

44%

(12)

0%

20%

40%

60%

80%

100%

Almost 90% of the respondents does not see added value in establishing a UIOLI mechanism between 
the LT and FDA one (Figure 85). Many stakeholders pointed out that the use of market measures, such 
as interruptible capacity and over-nomination can be more effective. 5 stakeholders (1 NRA, 3 TSOs, 1 
trader) did not respond. 

Figure 85: Answers to the question about the added value of a mid-term UIOLI mechanism 

Yes

12%

(3)

No

88%

(22)

0%

20%

40%

60%

80%

100%

Effectiveness and efficiency of CMPs 

The  questions  in  this  section  of  the  survey  focused  on  the  possible  improvement  of  the  CMPs 
effectiveness  and  efficiency  if  network  users  surrendering  capacity  to  the  TSO  were  also  allowed  to 
market the same capacity at the secondary market, if more detailed criteria for the activation of the LT 
UIOLI  mechanism  were  included  in  the  Guidelines,  and  if  a  more  refined  incentive  regime  for 
oversubscription could increase the additional capacity offered by the TSOs. 

Most stakeholders (71%) responded that surrendered capacity should not be offered at the same time 
at the primary and secondary market (Figure 86). Several stakeholders that responded either “yes” or 
“no” stressed that the risks of selling the same capacity twice should be avoided. All traders responded 

 
 
 
 
 
 
positively that they are interested in having the flexibility of surrendering capacity and being able to 
sell it at the secondary market. 2 stakeholders (TSOs) did not respond to the question. 

Figure 86: Answers to the question about the offering surrendered capacity to the secondary market 

29%

(8)

Yes

No

71%

(20)

0%

20%

40%

60%

80%

100%

Almost 90% of the respondents indicated that there is no value added in more detailed criteria for the 
LT  UIOLI  mechanism  (Figure  87).  Some  of  these  respondents  noted  that  the  existing  criteria  are 
sufficient  and  others  that  there  has  been  very  little  need  to  trigger  the  mechanism  in  practice  and 
therefore there is no need to have more detailed criteria in the regulations. Some also noted that with 
the expiry of the legacy contracts the usefulness of the LT UIOLI mechanism is becoming limited. 5 
stakeholders (2 NRAs, 3 TSOs) did not respond to the question. 

The questioned concerning the incentive scheme for oversubscription was answered by 12 out of 30 
stakeholders. Most respondents (58%) see no impact of the incentive scheme on offering additional 
capacity (Figure 88). 4 of the respondents of “no impact” are in Member States that have OS + BB 
rules in place but offer no additional capacity. A TSO currently applying FDA UIOLI indicated a “high 
impact” of incentives in offering additional capacity. The “moderate impact” response was indicated by 
stakeholders in systems with OS+BB rules in place, and some also offering additional capacity. 

Figure 87: Answers to the question about the further detailing of the UIOLI activation criteria 

Yes

12%

(3)

No

88%

(22)

0%

20%

40%

60%

80%

100%

 
 
 
 
 
 
Figure 88: Answers to the question about impact of the incentive scheme on the OS+BB application 

High impact – the incentive regime is the main 
driver for deciding the amount of additional 
capacity to be made available

8%

(1)

Moderate impact – the incentive regime is one of 
the drivers considered when assessing the amount 
of additional capacity to be made available

33%

(4)

No impact – the incentive regime has limited to no 
impact on the TSO’s decision on the amount of 
additional capacity to be made available

58%

(7)

0%

20%

40%

60%

80%

100%

Cross-border harmonization of CMPs 

The questions in this section of the survey focused on the impact of applying different measures (OS+BB 
and FDA, or market measures and CMPs) at the two sides of an IP, as well as the need to revise the 
Guidelines’ provisions on LT UIOLI to ensure a harmonized application by the TSOs.   

Many  stakeholders  did  not  respond  to  the  two  questions  regarding  the  adverse  impact  of  applying 
different mechanisms at the two sides on a cross-border IP; 16 stakeholders did not provide an answer 
for the first and 15 for the second question. Around 80% of the respondents indicated that they consider 
there  are  adverse  effects  to  the  use  of  capacity  if  different  short-term  congestion  management 
measures apply at the different sides of an IP (Figure 89). The respondents did not indicate specific 
evidence on IPs where use of capacity was hampered. They provided more general views such as that 
the same rules should apply for bundled products, and capacity may not be bundled, different rules 
may result in difficulties and confusion for the users and inefficient capacity allocation. 

Figure 89: Answers to the questions about the adverse impact of applying different mechanisms at the 
two sides on a cross-border IP 

Application of OS+BB and FDA UIOLI 

Application of market-based measures and CMPs 

Most stakeholders (67%) consider that the existing provisions for LT UIOLI are sufficient (Figure 90). 
Only one respondent considers that coordination between NRAs should be required, in order to offer 
bundled  capacity  in  the  market.  6  stakeholders  (2  NRAs,  2  TSOs,  2  traders)  did  not  respond  to  the 
question. 

 
 
 
 
 
 
Figure 90: Answers to the question about the need to harmonize LT UIOLI provisions 

The Guidelines should be further detailed and
specified to ensure a harmonized application of
the LT UIOLI mechanism

25%

(6)

The NRA must consult with the adjacent NRAs
before implementing the LT UIOLI mechanism

4%

(1)

The existing provisions of Point 2.2.5 are sufficient

67%

(16)

Other

4%

(1)

0%

20%

40%

60%

80% 100%

Transparency of information relating to CMPs 

The questions in this section of the survey focused on the importance of information on CMPs to the 
network users’ decision making.  

The average ratings provided by the stakeholders indicate a moderate impact of information concerning 
CMPs on the network users’ decisions to book capacity (Figure 91). Nevertheless, 2 out of 3 traders 
responding  to  this  question  showed  high  or  very  high  interest  in  the  publication  of  information.  13 
stakeholders did not respond to the questionnaire. 

Figure 91 Answers to the question about rating the impact of information relating to CMPs on the 
network users’ decision making276 

276 Rating from 1 – 4 with 1 indicating low importance and 4 very strong importance. Average from all responses (except N/A) are 

presented. 

 
 
 
 
 
 
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