State of implementation of the third energy package in the gas sector. (Part 2), Interoperability and data exchange rules, and congestion management procedures.
Date: 2019-11-07
Institutions: Joint Research Centre
Subjects: EU competition policy, cross-border cooperation, data transmission, energy law, energy policy, gas industry, market, price of energy, report, retail trade, supplier

State of implementation  
of the Third Energy Package  
in the gas sector (Part 2) 

Interoperability and 
data exchange rules, 
and congestion 
management 
procedures 

Costescu A., Manitsas E., Szikszai A. 

2019 

EUR 29807 EN  

 
 
This publication is a Science for Policy report by the Joint Research Centre (JRC), the European Commission’s 
science and knowledge service. It aims to provide evidence-based scientific support to the European 
policymaking process. The scientific output expressed does not imply a policy position of the European 
Commission. Neither the European Commission nor any person acting on behalf of the Commission is 
responsible for the use that might be made of this publication. 

Contact information 
Name: 
Address: 
Email: 
Tel.: 

Anca COSTESCU 
European Commission, Joint Research Centre, P.O. box 2, 1755 ZG, Petten, the Netherlands 
Anca.COSTESCU@ec.europa.eu  
+31 22456-5173 

JRC Science Hub 
https://ec.europa.eu/jrc 

JRC115120 

EUR 29807 EN 

PDF 

ISBN 978-92-76-08850-9 

ISSN 1831-9424 

doi:10.2760/725855 

Luxembourg: Publications Office of the European Union, 2019 

© European Union, 2019 

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How to cite this report: Costescu A., Manitsas E., Szikszai A., State of implementation of the Third Energy 
Package in the gas sector (Part 2) - Interoperability and data exchange rules, and congestion management 
procedures, EUR 29807 EN, Publications Office of the European Union, Luxembourg, 2019, ISBN 978-92-76-
08850-9, doi: 10.2760/725855, JRC115120 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Contents 

Abstract ............................................................................................................... 1 

Authors ................................................................................................................ 2 

Executive summary ............................................................................................... 3 

1  Introduction ...................................................................................................... 5 

2  Network Code on Interoperability and Data Exchange Rules .................................... 6 

2.1  Principles .................................................................................................... 6 

2.2  Preparation ................................................................................................. 7 

2.3  Monitoring .................................................................................................. 8 

2.4  Legal Background ........................................................................................ 8 

2.5  Scope ......................................................................................................... 9 

2.6  Deadlines ................................................................................................... 9 

2.7  Definitions .................................................................................................. 9 

2.8  Regulated areas ........................................................................................ 10 

  Interconnection Agreement (IA) .......................................................... 10 

2.8.1.1  Overview of network use and operation .......................................... 10 

2.8.1.2  Flow control ................................................................................ 11 

2.8.1.3  Measurement .............................................................................. 12 

2.8.1.4  Matching ..................................................................................... 14 

2.8.1.5  Allocation .................................................................................... 15 

2.8.1.6  Communication procedure in case of exceptional event..................... 16 

2.8.1.7  Dispute settlement ....................................................................... 16 

2.8.1.8  IA amendment ............................................................................ 16 

2.8.1.9  Monitoring results ........................................................................ 16 

2.9  Units ........................................................................................................ 17 

2.10 

Gas quality and Odourisation ................................................................. 18 

 Gas quality ....................................................................................... 18 

 Odourisation ..................................................................................... 20 

2.11 

Data Exchange .................................................................................... 20 

3  Congestion Management Procedures in Gas Transmission Systems ........................ 23 

3.1  Legislation ................................................................................................ 23 

3.2  Principles .................................................................................................. 23 

3.3  Overview of CMP ....................................................................................... 24 

  General provisions ............................................................................. 24 

  Capacity increase through oversubscription and buy-back scheme ........... 24 

  Firm day-ahead use-it-or-lose-it mechanism ......................................... 24 

  Surrender of contracted capacity ......................................................... 25 

i 

  Long-term use-it-or-lose-it mechanism ................................................. 25 

3.4  Guidance on best practices for CMP .............................................................. 25 

  Oversubscription and buy-back scheme ................................................ 25 

  Firm day-ahead use-it-or-lose-it mechanism ......................................... 26 

  Capacity surrender ............................................................................. 27 

  Long-term use-it-or-lose-it mechanism ................................................. 27 

3.5  Status of Implementation ........................................................................... 27 

  ACER ................................................................................................ 27 

  ENTSOG ........................................................................................... 30 

References ......................................................................................................... 33 

List of abbreviations and definitions ....................................................................... 35 

List of figures ...................................................................................................... 36 

List of tables ....................................................................................................... 37 

Annexes ............................................................................................................. 38 

ii 

Abstract 

In  the  context  of  the  Third  Energy  Package,  we  complement  the  regulatory  elements 
provided  in  our  previous  report  on  the  State  of  implementation  of  the  Third  Energy 
Package  in  the  gas  sector  by  reviewing  two  other  network  codes.  This  allows  the  full 
understanding  of  the  rules  which  are  at  the  core  of  the  gas  market  in  the  European 
Union. 

1 

Authors 

Anca  Costescu  (PhD),  Scientific  officer  at  European  Commission,  Joint  Research  Centre, 
Directorate C: Energy, Transport and Climate, Energy Security, Distribution and Markets 
Unit. 

Efthymios  Manitsas  (PhD),  Scientific  officer  at  European  Commission,  Joint  Research 
Centre, Directorate C:  Energy,  Transport and  Climate, Energy Security, Distribution and 
Markets Unit. 

Andras  Szikszai,  Scientific  officer  at  European  Commission,  Joint  Research  Centre, 
Directorate C: Energy, Transport and Climate, Energy Security, Distribution and Markets 
Unit. 

2 

Executive summary 

The key objective of this report is to complement a previous report (1) by introducing the 
Network  Code  on  Interoperability  and  Data  exchange  rules,  and  the  Congestion 
Management Procedures.  

Policy context 

An  integrated  EU  energy  market  is  the  most  cost-effective  way  to  ensure  secure  and 
affordable  supplies  to  EU  citizens.  Through  common  energy  market  rules  and  cross-
border  infrastructure,  energy  can  be  produced  in  one  EU  country  and  delivered  to 
consumers  in  another.  This  keeps  prices  in  check  by  creating  competition  and  allowing 
consumers to choose energy suppliers. 

The  Third  Energy  Package  has  been  enacted  to  improve  the  functioning  of  the  internal 
energy market and resolve structural problems. It covers five main areas: 

-  unbundling energy suppliers from network operators 

- 

- 

- 

- 

strengthening the independence of regulators 

establishment of the Agency for the Cooperation of Energy Regulators (ACER) 

cross-border  cooperation  between  transmission  system  operators  (TSO)  and  the 
creation of European Networks for Transmission System Operators for Gas (ENTSOG) 

increased transparency in retail markets to benefit consumers. 

Energy  is  often  bought  and  sold  on  wholesale  markets  before  reaching  the  final 
consumer.  To  ensure  the  smooth  functioning  of  these  markets  and  prevent  price 
manipulation,  the  EU  has  enacted  regulations  which  prohibit  the  use  of  insider 
information  or  the  spreading  of  incorrect  information  concerning  supply,  demand,  and 
prices. 

The  EU  also  establishes  rules  on  the  use  of  cross-border  energy  networks.  Known  as 
network  codes,  these  rules  regulate  who  can  use  cross-border  infrastructure  and  under 
what conditions. 

In this policy context, the report gives a short overview of two Network Codes.  

Key conclusions 

As  the  market  integration  is  a  process  resulting  from  the  EU  legislation,  and  is  based, 
among others, on cross-border cooperation and infrastructure use and development, we 
study in more details two of the Network Codes on gas. 

Main findings 

The  adoption  of  the  Network  Codes  increases  transparency,  fair  access  to  cross-border 
trade  and  flexibility  for  the  supply  leading  to  a  more  attractive  environment  for  the 
markets  participants.  If  they  are  in  place  in  all  the  member  states  it  is  likely  for  the 
related hubs to develop. It is hence very important to understand their implementation. 

Related and future JRC work 

This is the second report in a series related to the gas market(s) in EU. In the future, the 
work will be continued by selecting data sources regarding gas demand and gas prices in 

(1)   Costescu  A,  Manitsas  E.,  Szikszai  A.,  State  of  implementation  of  the  Third  Energy  Package  in  the  gas 
sector,  EUR  29102  EN,  Publications  Office  of  the  European  Union,  Luxembourg,  2018,  ISBN  978-92-79-
79365-3, doi:10.2760/533990, JRC110507 
(https://ec.europa.eu/jrc/en/publication/eur-scientific-and-technical-research-reports/state-
implementation-third-energy-package-gas-sector). 

3 

                                           
 
the EU, and available models to analyse them, with possible description of links to other 
markets (electricity, oil or other regions). 

The  monitoring  of  the  state  of  implementation  of  the  Third  Energy  Package  will  also  be 
continued. 

Quick guide 

This report is structured as follows. Section 1 introduces the analysis. Section 2 gives an 
overview of the Network Code on Interoperability and Data Exchange Rules and Section 3 
presents the Congestion Management Procedures in Gas Transmission Systems. 

4 

1  Introduction 

The  purpose  of  this  report  is  to  complement  the  report  "State  of  implementation  of  the 
Third Energy Package in the gas sector" of 2017 (1) by presenting the Network Code (NC) 
on  Interoperability  and  Data  exchange  rules  (2)  (INT  NC),  and  the  Congestion 
Management  Procedures  (3)  (CMP).  Report  (1)  gave  an  overview  of  the  gas  related  EU 
legislation,  and  presented  the  EU  gas  markets,  including  the  Gas  Target  Model  (GTM), 
the metrics used by different actors to define a well-functioning market, the existing EU 
gas  hubs,  and  their  scoring  using  these  different  metrics.  Furthermore,  it  gave  a 
description  of  three  NCs:  Gas  Balancing,  Capacity  Allocation  Mechanisms,  and 
Harmonized Transmission Tariffs.  

An  NC  is  a  set  of  common  EU-wide  rules  in  the  form  of  an  EU  regulation  established in 
accordance  with  the  process  in  Article  6  of  the  Gas  Regulation  (4)  for  a  given  subject 
matter. NCs supplement the Gas Regulation and "amend… [its] non-essential elements". 

All  NCs  constitute  and  form  integral  parts  of  the  Gas  Regulation;  its  consistent  and 
coherent implementation requires due consideration of the interactions between the Gas 
Regulation and any given NC, and between NCs.  

(2)   Commission Regulation (EU) No 2015 / 703 of 30 April 2015 establishing a network code on interoperability 

and data exchange rules 
(https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:JOL_2015_113_R_0003). 

(3)   Annex  I,  point  2.2  (Congestion  management  procedures  in  the  event  of  contractual  congestion)  of 

Regulation EC No 715/2009 (4). 

(4)   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 and repealing Regulation (EC) No 1775 / 2005 
(https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32009R0715). 

5 

                                           
 
 
2  Network Code on Interoperability and Data Exchange 

Rules 

2.1  Principles 

In  order to create the common market for natural gas, the management of  (sometimes 
unjustified)  technical  constraints  is  just  as  important  as  dealing  with  all  other,  mostly 
commercial, issues. This is the aim of INT NC, the most technical Network Code. 

Market liberalisation has fundamentally changed the set-up of natural gas supply system. 

"Before the opening of the electricity and gas sectors, a single party could be responsible 
for: 

• operating the infrastructures (transmission, distribution, liquefied natural gas 
(LNG), storage); 

• inputting gas in the system, either from national sources of production or 
through contracts with other countries; 

• off-taking gas from the system in order to supply consumers or distribution 
systems; 

• the local commercialising of natural gas. 

Necessary  technical  and  operational  rules  and  procedures  were  then  internal  to  the 
integrated company." (5) 

A  more  tangible interpretation  of  the  purpose  of  this  particular  network  code  is  to  have 
market  participants  perceive  the  several  transmission  systems  as  it  was  one  single 
system run by a sole operator. 

"Ideally, in a  fully integrated  system, the interoperability level is  such that users of two 
or  more  transmission  systems  operated  by  separate  entities  in  Europe  do  not  face 
technical,  operational,  communications  or  business-related  barriers  higher  than  those 
that would have been reasonably expected, if the relevant networks had been efficiently 
operated by a single entity" (5) 

In  order  to  reach  the  goal  above,  varied  terms  and  conditions  of  bilateral  agreements 
between system operators need to be harmonised to the highest reasonable level. This is 
the purpose of INT NC. 

Another  peculiarity  of  this  NC  is  that  while  the  more  commercial  ones  can  more  easily 
impose  certain  rules  on  market  participants,  it  is  not  necessarily  the  case  for  technical 
standards.  Due  to  the  fact  the  INT  NC  deals  primarily  with  the  technical  aspects  of 
facilitating a liquid market, meeting certain requirements (e.g. gas quality, odourisation, 
data exchange) could incur significant costs. As a result the NC requires CBAs in order to 
ensure that costs do not outweigh benefits. 

Besides the utilitarian aspect there is another challenge that INT NC faces. The NC needs 
to find the balance between certainty and flexibility. Network users naturally want to see 
set standards for the natural gas that they intend to transport through an interconnection 
point  (IP)  and  for  the  systems  they  use  for  their  long  term  business  purposes.  On  the 
other  hand  precise  standards  can  make  the  system  rigid  and  can  be  an  obstacle  to  the 
use of new sources and management of supply crises. 

In  order  to  meet  the  legislative  principles,  INT  NC  intends  to  enable  high  level 
interoperability for a common energy market and – at the same time – set certain rules 

(5)   Initial Impact Assessment accompanying the document Framework Guidelines on Interoperability and Data 

Exchange Rules for European Gas Transmission Networks (ACER 2012) 
(https://www.acer.europa.eu/Official_documents/Acts_of_the_Agency/Framework_Guidelines/Related%20
documents/Initial%20Impact%20Assessment%20(IIA)_ENTSOG.pdf). 

6 

                                           
 
for  data  exchange  which  is  an  integral  part  of  harmonising  technical  conditions. 
Consequently the network code is focusing on the following areas: 

"Interconnection  agreements,  units,  gas  quality  and  odourisation,  capacity  calculation 
and  data  exchange  are  the  areas  where  barriers  to  the  efficient  functioning  of  the 
Internal  Gas  Market  have  been  identified  by  the  Agency  and  for  which  a  common 
approach  based  on  harmonised  rules  could  smooth  the  interoperation  of  systems, 
including communication." (6) 

2.2  Preparation 

The  extent  to  which  regulatory  involvement  is  necessary  has  been  studied  in  details  by 
ACER  in  the  Initial  Impact  Assessment  accompanying  the  Framework  Guidelines  on 
Interoperability  and  Data  Exchange  Rules  for  European  Gas  Transmission  Networks  of 
2012 ("Impact Assessment"). Possible involvement was ranging between "no action" and 
"full harmonisation" in all areas. 

The table below shows the range of options by areas and the final decision: 

Table 1. Regulated areas, options and decisions 

AREAS 

OPTIONS 

DECISION 

Interconnection Agreement    No further EU action 
  Setting of minimum 

Setting of default rules 

Units 

Gas Quality 

Odourisation 

Data Exchange 

requirements 

  Setting of default rules 

  Fully detailed IA in INT 
NC (full harmonisation) 

  No further EU action 

  Full harmonisation 

  No further EU action 

  Reinforced requirements 
in terms of monitoring 
and cooperation 

  Full harmonisation 

  No further EU action 

 

Increased transparency 
and TSO cooperation 

  Full harmonisation 

  No further EU action 

  Format harmonisation 

  Format and content 
harmonisation 

Full harmonisation 

Reinforced  requirements  in 
terms  of  monitoring  and 
cooperation 

Full harmonisation 

Format harmonisation 

(6)   Framework  Guidelines  on  Interoperability  and  Data  Exchange  Rules  for  European  Gas  Transmission 

Networks (ACER 2012) 
(https://www.acer.europa.eu/Official_documents/Acts_of_the_Agency/Framework_Guidelines/Related%20
documents/FG%20on%20Interoperability%20and%20Data%20Exchange%20Rules%20for%20European%
20Gas%20Transmission%20Networks.pdf). 

7 

                                           
2.3  Monitoring 

"1. The Agency shall monitor the execution of the tasks referred to in Article 8 (1), (2) 
and (3) of the ENTSO for Gas and report to the Commission." [Gas Regulation Article 9]  

In most areas INT NC has adopted a kind of "permissive" guidance. Therefore – besides 
the compliance with mandatory rules – the evaluations took into account the fulfilment of 
goals that brought the network code into existence. 

"The Report assesses the effectiveness of the Code implementation and is not limited to 
checking the mere legal compliance." (7) 

Both ACER and ENTSOG have carried out an implementation monitoring, according to the 
Gas Regulation. Both  entities sent out a survey to MSs to  monitor the status of  INT  NC 
implementation.  The  ENTSOG  survey  ("quantitative  analysis")  targeted  TSOs  and 
received  information  on  90  IPs,  while  ACER  sent  out  another  survey  –  based  on  the 
survey of ENTSOG – to be filled out jointly by TSOs and National Regulatory Authorities 
(NRAs). The reason for the second survey is that – according to ACER – the first survey 
was  based  on  self-evaluation  and  the  answers  were  not  supported  by  evidence.  Both 
survey templates are attached to this document. 

Besides  the  surveys  ACER  conducted  another  assessment  ("qualitative  analysis")  by 
reviewing  the  implementation  of  INT  NC  at  particular  IPs  on  8  borders  in  the  following 
areas: 

"We assess the following features: 

a. Interconnection Agreements; 

b. Data Exchange, and 

c. Gas Quality and Odourisation." (7) 

The  results  of  the  assessment  of  the  above  features  will  be  introduced  in  details  in  the 
relevant sections. Before coming to the details of the analysis it is worth to mark that no 
major issues have emerged in the implementation of INT NC. 

"Neither  stakeholders  nor  NRAs  reported  any  systemic  problems  in  relation  to  the 
implementation of the Code. Overall, the implementation is progressing as expected." (7) 

2.4  Legal Background 

The title of the INT NC itself is very broad and generic so numerous stipulations could be 
quoted from the Directive and Regulations of the Third Energy Package that are related 
one  way  or  the  other  to  the  operation  of  the  natural  gas  supply  system  or  the  flow  of 
information.  As  a  result  all  technical  issues  that  can  hinder  the  evolution  of  a  common 
market  and  need  to  be  sorted  out  mainly  between  system  operators  can  fit  under  the 
umbrella of INT NC. So the most relevant rules are: 

DIRECTIVE 2009/73/EC concerning common rules for the internal market in natural gas 
and repealing Directive 2003/55/EC (Directive) 

As part of the 3rd Energy Package Directive "The regulatory authorities where Member 
States have so provided or  Member States shall ensure that technical safety criteria 
are  defined  and  that  technical  rules  establishing  the  minimum  technical  design  and 
operational  requirements  for  the  connection  to  the  system  of  LNG  facilities,  storage 
facilities,  other  transmission  or  distribution  systems,  and  direct  lines,  are  developed 
and  made  public.  Those  technical  rules  shall  ensure  the  interoperability  of  systems 
and shall be objective and non-discriminatory." [Directive Article 8]  

(7)   First ACER Implementation Monitoring Report of the Network Code on Interoperability and Data Exchange 
(https://www.acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/First%20ACER%20Imple
mentation%20Monitoring%20Report%20of%20the%20Network%20Code%20on%20Interoperability%20an
d%20Data%20Exchange.pdf). 

8 

                                           
 
Furthermore  "…Member  States  shall  ensure  that  the  roles  and  responsibilities  of 
transmission  system  operators,  distribution  system  operators,  supply  undertakings 
and  customers  and  if  necessary  other  market  parties  are  defined  with  respect  to 
contractual arrangements, commitment to customers, data exchange and settlement 
rules, data ownership and metering responsibility. 

Those  rules  shall  be  made  public,  be  designed  with  the  aim  to  facilitate  customers’ 
and  suppliers’  access  to  networks  and  they  shall  be  subject  to  review  by  the 
regulatory authorities or other relevant national authorities." [Directive Article 45] 

REGULATION (EC) No 715/2009 on conditions for access to the natural gas transmission 
networks 

The Gas Regulation gives a concrete statement on the necessity of the establishment 
of a NC on interoperability and data exchange: 

"The network codes referred to in paragraphs 1 and 2 shall cover the following areas, 
taking into account, if appropriate, regional special characteristics:  

… 

(d) data exchange and settlement rules; 

(e) interoperability rules; 

…"  

[Gas Regulation Article 8(6)] 

REGULATION (EU) No 2015/703 establishing a network code on interoperability and data 
exchange rules 

INT NC sets the detailed rules and will be analysed in this section.  

2.5  Scope 

Generally the scope of INT NC is the interconnection points (IPs), if the stipulations refer 
differently,  it  is  indicated.  As  ACER  pointed  out  (5)  the  interpretation  of  scope  can  be 
wider than transmission system operators [certain distribution system, storage and  LNG 
operators],  but  INT  NC  clearly  states  that  it  primarily  focuses  on  "interoperability  and 
data  exchange  as  well  as  harmonised  rules  for  the  operation  of  gas  transmission 
systems"  

2.6  Deadlines 

By default the requirements set out in the INT NC were to be fulfilled by May 2016. The 
only exception is the Interconnection Agreement (IA) template that was to be published 
by ENTSOG by 31 December 2015.  

2.7  Definitions 

‘exceptional event’ means any unplanned event  that  is  not  reasonably controllable 
or  preventable and  that  may cause, for a limited period, capacity  reductions, affecting 
thereby  the  quantity  or  quality  of  gas  at  a  given  interconnection  point,  with  possible 
consequences on interactions between transmission system operators as well as between 
transmission system operator and network users; [INT NC Article 2(a)] 

‘initiating  transmission  system  operator’  means  the  transmission  system  operator 
initiating  the  matching  process  by  sending  the  necessary  data  to  the  matching 
transmission system operator; [INT NC Article 2(b)] 

‘lesser rule’  means that,  in  case  of  different  processed quantities at either side  of  
an    interconnection  point,  the  confirmed  quantity  will  be  equal  to  the  lower  of  the  two 
processed quantities. [INT NC Article 2(c)] 

9 

‘matching  process’  is  the  process  of  comparing  and  aligning  processed  quantities  of 
gas for  network users  at both sides  of a specific interconnection  point, which results in 
confirmed quantities for the network users; [INT NC Article 2(d)] 

‘matching  transmission  system  operator’  means  the  transmission  system  operator 
performing the matching process and sending the result  of the matching process to the 
initiating transmission system operator; [INT NC Article 2(e)] 

‘measured  quantity’  means  the  quantity  of  gas  that,  according  to  the  measurement 
equipment  from  the  transmission  system  operator,  has  physically  flowed  across  an 
interconnection point per time period; [INT NC Article 2(f)] 

‘operational  balancing  account’  means  an    account  between  adjacent  transmission 
system operators,  to  be  used  to manage steering  differences  at  an  interconnection 
point    in    order    to    simplify    gas    accounting  for    network  users  involved  at  the 
interconnection point; [INT NC Article 2(g)] 

‘processed  quantity’  means  the  quantity  of  gas  determined  by  the  initiating 
transmission system operator and by the matching transmission system operator, which 
takes  into  account  the  network  user's  nomination  or  re-nomination  and  contractual 
provisions  as  defined  under  the  relevant  transport  contract  and  which  is  used  as  the 
basis for  the matching process; [INT NC Article 2(h)] 

‘steering   difference’ means the   difference   between the  quantity  of  gas   that   the  
transmission  system operators had scheduled to  flow and the  measured quantity  for an 
interconnection point. [INT NC Article 2(i)] 

'interconnection  agreement'  means  an  agreement  entered 
into  by  adjacent 
transmission  system  operators,  whose  systems  are  connected  at  a  particular 
interconnection  point,  which  specifies  terms  and  conditions,  operating  procedures  and 
provisions,  in  respect  of  delivery  and/or  withdrawal  of  gas  at  the  interconnection  point 
with  the  purpose  of 
interconnected 
transmission networks. [COMMISSION REGULATION (EU) 2017/459 Article 3(9) (8)] 

interoperability  of  the 

facilitating  efficient 

2.8  Regulated areas 

Interconnection Agreement (IA) 

2.8.1.1  Overview of network use and operation 

In order to help understand the IA related rules of INT NC, it is useful to locate its scope 
in the sequence of acts concerning network use and operation.  

The  two  main  market  participants  –  network  users  and  system  operators  –  follow 
generally the sequence of acts as outlined below: 

1.  Capacity made available for purchase (booking) - by system operator 

2.  Capacity booking – by network user 

3.  (Re) Nomination – by network user 

4.  Processing, matching, confirming and scheduling – by system operator 

5.  Steering (including operational balancing) – by system operator 

6.  Measurement – by system operator 

7.  Allocation (including commercial balancing) – by system operator 

(8)   COMMISSION  REGULATION  (EU)  2017/459  of  16  March  2017  establishing  a  network  code  on  capacity 

allocation mechanisms in gas transmission systems and repealing Regulation (EU) No 984/2013 

10 

 
                                           
The  above  points  are  naturally  not  as  distinct  in  time  as  they  look.  Some  steps  can 
overlap, e.g. the operational activities during the gas day can occur simultaneously with 
a  renomination  cycle.  This  section  of  the  network  code  gives  guidance  on  points  3-7, 
shaping the frames of the Interconnection Agreement which is mandatory between TSOs. 

"Individual Interconnection Agreements shall be established on a mandatory basis by all 
concerned TSOs at all interconnection points." (6) 

These  agreements  are  concluded  between  the  operators  of  adjacent  transmission 
systems with a view to set terms and conditions in the following areas: 

"Adjacent  transmission  system  operators  shall  ensure  that  at  least  the  following  terms 
and conditions detailed in Articles 6 to 12 are covered by an interconnection agreement 
in respect of each interconnection point:  

(a) rules for flow control;  

(b) measurement principles for gas quantities and quality;  

(c) rules for the matching process;  

(d) rules for the allocation of gas quantities;  

(e) communication procedures in case of exceptional events;  

(f) settlement of disputes arising from interconnection agreements;  

(g) amendment process for the interconnection agreement." [INT NC Article 3] 

For  transparency  and  proper  representation  of  network  users'  interest  INT  NC  gives 
guidance on the process of conclusion and amendment of an IA. 

"1.  The  transmission  system  operators  shall  identify  the  information  contained  in 
interconnection  agreements  that  directly  affects  network  users  and  shall  inform  them 
thereof.  

2.  Before  concluding  or  amending  an  interconnection  agreement  …  transmission  system 
operators  shall  invite  network  users  to  comment  on  the  proposed  text  of  those  ...  The 
transmission  system  operators  shall  take  the  network  users'  comments  into  account 
when concluding or amending their interconnection agreement.  

3.  The  mandatory  terms  of  interconnection  agreements  listed  in  Article  3  or  any 
amendments  thereof  concluded  after  the  entry  into  force  of  this  Regulation  shall  be 
communicated  by  the  transmission  system  operators  to  their  national  regulatory 
authority  and  to  ENTSOG  ...  Transmission  system  operators  shall  also  communicate 
interconnection  agreements  upon  request  of  competent  national  authorities  of  the 
Member State ..." 

ENTSOG  has  published  a  template  for  an  IA,  so  in  case  the  parties  concerned  are  not 
able  to  come  to  an  agreement  on  a  certain  issue  it  is  available  to  fall  back  on. 
Furthermore,  since  this  section  of  the  INT  NC  deals  with  the  requirement  of  an 
agreement  also  default  contents  have  been  identified  that  are  compulsory  elements  of 
the agreement in case the parties concerned cannot reach a consensus in a certain area. 

2.8.1.2  Flow control 

With regards to flow control the main guiding principles are that flows are 

1.  "(a) … controllable, accurate, predictable and efficient …;" [INT NC Article 6(1)] 

2.  steered  "(b)  …  for  minimising  the  deviations  from  the  flow  pursuant  to  the 

matching process"; (steering difference) [INT NC Article 6(1)] 

The above rules  serve two main purposes. On  the one hand the system operator needs 
to  act  in  accordance  with  the  needs  and  requirements  of  network  users,  on  the  other 
hand they need to maintain safe operation and system integrity.  

11 

"The transmission system operator designated … shall be responsible for steering the gas 
flow across the interconnection point …:  

(a) at a level of accuracy sufficient to minimise the steering difference; and  

(b)  at  a  level  of  stability  in  line  with  the  efficient  use  of  the  gas  transmission 
networks." [INT NC Article 6(2)] 

With regards to flow control the IA has to contain the rules for  

1.  The system operator that is responsible for steering the gas across the IP; 

2.  The  decision  on  the  direction  and  quantity  of  gas  flowing  through  the  IP  in  an 
hourly  breakdown  according  to  the  matching  process  and  the  settlement  of 
steering difference; 

3.  Arrangements for managing quality and odourisation practice differences; 

"(c) designate the transmission system operator  who is responsible for  steering the gas 
flow across the interconnection point." [INT NC Article 6(2)] 

"3.  The  quantity  and  direction  of  the  gas  flow  decided  by  the  adjacent  transmission 
system operators shall reflect:  

(a) the result of the matching process;  

(b) the operational balancing account correction; 

…  

(d) any arrangement managing cross-border trade restrictions due to gas quality 
differences … and/or odourisation practices ..." [INT NC Article 6] 

Furthermore  INT  NC  ensures  the  opportunity 
crisis/exceptional event: 

for  efficient  management  of  a 

"4.  A  transmission  system  operator  may  decide  to  alter  the  quantity  of  gas  or  the  gas 
flow direction or both, if this is needed, in order to:  

(a)  comply  with  provisions  laid  down  in  national  or  Union  safety  legislation 
applicable to the interconnection point;  

(b) comply with requirements laid down in Emergency Plans and Preventive Action 
Plans developed in accordance with Regulation (EU) No 994/2010 of the European 
Parliament and of the Council (1);  

(c) react in case the operator's system is affected by an exceptional event." [INT 
NC Article 6] 

Default rule: 

The rule determines the responsibility of steering the gas flow. 

"If  the  adjacent  transmission  system  operators  fail  to  agree  on  this  designation,  the 
transmission  system  operator  that  operates  the  flow  control  equipment  shall,  in 
cooperation  with  the  other  transmission  system  operator(s),  be  responsible  for  steering 
the gas flow across the interconnection point." [INT NC Article 6(2)] 

2.8.1.3  Measurement 

Measurement  rules  cover  the  volume,  energy  and  quality  of  gas.  The  IA  has  to  identify 
the party responsible for the installation, operation and maintenance of the measurement 
equipment  and  supply  of  necessary  data  to  the  adjacent  system  operator.  The  two 
operators shall agree on the measurement principles.  

12 

 
 
"3.  The  adjacent  transmission  system  operators  shall  agree  on  measurement  principles 
which shall at least include:  

(a)  a  description  of  the  metering  station  including  measurement  and  analysis 
equipment to be used and details of any secondary equipment that may be used 
in case of failure;  

(b) the gas quality parameters and volume and energy that shall be measured, as 
well  as  the  range  and  the  maximum  permissible  error  or  uncertainty  margin 
within  which  the  measurement  equipment  shall  operate,  the  frequency  of 
measurements, in what units and according to what standards the measurement 
shall be made as well as any conversion factors used;  

(c) the procedures and methods that shall be used to calculate those parameters 
which are not directly measured;  

(d)  a  description  of  the  method  of  calculation  in  respect  of  the  maximum 
permissible error or uncertainty in the determination of energy transported;  

(e)  a  description  of  the  data  validation  process  in  use  for  the  measured 
parameters;  

(f)  the  measurement  validation  and  quality  assurance  arrangements,  including 
verification  and  adjustment  procedures  to  be  agreed  between  the  adjacent 
transmission system operators;  

(g)  the  way  data,  including  frequency  and  content,  is  provided  among  the 
adjacent transmission system operators in respect of the measured parameters; 

(h)  the  specific  list  of  signals  and  alarms  to  be  provided  by  the  adjacent 
transmission  system  operator(s)  who  operate(s)  the  measurement  equipment  to 
the other adjacent transmission system operator(s);  

(i) the method of determining a correction to a measurement and any subsequent 
procedures  that  may  be  necessary  in  a  temporary  situation  where  the 
measurement  equipment  is  found  to  be  or  have  been  in  error  (either  under-
reading or over-reading outside of its defined uncertainty range).This transmission 
system operator shall take appropriate action to end this situation.  

(j)  rules  that  shall  apply  between  adjacent  transmission  system  operators  in  the 
event of failure of the measurement equipment;  

(k) rules that shall apply between the adjacent transmission system operators for:  

(i) access to the measurement facility;  

(ii) additional verifications of measurement facility;  

(iii) modification of the measurement facility;  

(iv) attendance during calibration and maintenance work at the 
measurement facility." [INT NC Article 7] 

Default rules: 

If there is no agreement between TSOs the one in control of the measuring equipment is 
responsible and European standard EN1176 is applicable for the functional requirement. 

"4.  If  the  adjacent  transmission  system  operators  fail  to  comply  with  their  obligations 
provided for in paragraphs 1 and 3:  

(a)  the  transmission  system  operator  in  control  of  the  measurement  equipment 
shall  be  responsible  for  the  installation,  operation  and  maintenance  of  such 
equipment and for providing the other transmission system operator with the data 
regarding  the  measurement  of  gas  flows  at  the  interconnection  point  in  a  timely 
manner;  

13 

(b)  the  European  standard  EN1776  ‘Gas  Supply  Natural  Gas  Measuring  Stations 
Functional  Requirements’  in  the  version  applicable  at  the  time  shall  apply."  [INT 
NC Article 7] 

2.8.1.4  Matching 

Based on (re-)nominations the system operators need to establish a matching process so 
the same quantity can be scheduled for the two sides of the IP. By default the lesser rule 
applies, meaning that the lower quantity prevails if the quantities on the two sides differ. 
TSOs  can  agree  on  a  different  matching  process  as  well.  The  system  operators  have  to 
agree on the process including their roles, timing, data exchange. 

"2. Nominations and re-nominations shall be managed in accordance with the following: 

(a)  the  application  of  a  matching  rule  shall  lead  to  identical  confirmed  quantities 
for  each  pair  of  network  users  at  both  sides  of  the  interconnection  point  when 
processed quantities are not aligned;  

(b)  the  adjacent  transmission  system  operators  may  agree  to  maintain  or 
implement a matching rule other than the lesser rule, …;  

(c)  the  adjacent  transmission  system  operators  shall  specify  …  whether  they  are 
the initiating or the matching transmission system operator;  

(d)  the  adjacent  transmission  system  operators  shall  specify  the  applicable  time 
schedule  for  the  matching  process  within  the  nomination  or  re-nomination  cycle, 
… and shall take into account:  

(i) the data that needs to be exchanged between the adjacent transmission 
system operators …;  

(ii)  the  data  exchange  process  …  shall  enable  the  adjacent  transmission 
system operators to perform all calculation and communication steps in an 
accurate and timely manner." [INT NC Article 8] 

INT NC sets a minimum data content for the matching process. 

"4.  Each  interconnection  agreement  shall  specify  in  its  provisions  on  data  exchange  for 
the matching process:  

… 

(b)  the  harmonised  information  contained  within  the  data  exchange  for  the 
matching process which shall contain at least the following:  

(i) interconnection point identification;  

(ii) network user identification or if applicable its portfolio identification; 

(iii)  identification  of  the  party  delivering  to  or  receiving  gas  from  the 
network user or if applicable its portfolio identification;  

(iv) start and end time of the gas flow for which the matching is made;  

(v) gas day;  

(vi) processed and confirmed quantities;  

(vii) direction of gas flow." [INT NC Article 8] 

Default rules: 

For the lack of agreement, INT NC sets the rules for the applicable quantity, the steps of 
matching process and determines the "matching system operator".  

"5.  Unless  otherwise  agreed  by  the  adjacent  transmission  system  operators  in  their 
interconnection agreement, the following shall apply:  

14 

 
(a) the transmission system operators shall use the lesser rule. …  

(b) the transmission system operator in control of the flow control equipment shall 
be the matching transmission system operator;  

(c)  the  transmission  system  operators  shall  perform  the  matching  process  in  the 
following sequential steps:  

(i)  calculating  and  sending  of  processed  quantities  of  gas  by  the  initiating 
transmission  system  operator  within  45  minutes  of  the  start  of  the 
nomination or re-nomination cycle;  

(ii) calculating and sending of confirmed quantities of gas by the matching 
transmission  system  operator  within  90  minutes  from  the  start  of  the 
nomination or re-nomination cycle;  

(iii)  sending  confirmed  quantities  of  gas  to  network  users  and  scheduling 
the gas flow across the interconnection point by the adjacent transmission 
system operators within two hours from the start of the nomination or re-
nomination cycle. ..." [INT NC Article 8] 

2.8.1.5  Allocation 

The  quantity  allocated  to  the  network  users  has  to  be  equal  on  both  sides  of  the  IP.  In 
case  steering  difference  is  managed  through  an  operational  balancing  account,  system 
operators need to agree on the limit of the operational balancing account and its possible 
extension.  

"1.  In  respect  of  the  allocation  of  gas  quantities,  the  adjacent  transmission  system 
operators  shall  establish  rules  ensuring  consistency  between  the  allocated  quantities  at 
both sides of the interconnection point.  

… 

4. The adjacent transmission system  operators may agree to maintain or implement an 
allocation  rule  other  than  the  operational  balancing  account,  provided  that  this  rule  is 
published  and  network  users  are  invited  to  comment  on  the  proposed  allocation  rule 
within at least two months after publication of the allocation rule." [INT NC Article 9] 

Default rules: 

The rules delegate the task of (re)calculating the operational balancing account, declare 
that  allocations  shall  be  equal  to  confirmed  quantities,  the  necessity  of  taking  specific 
characteristics  of  IPs  into  account  for  the  operational  balancing  account  limits  and  the 
aim to maintain the operational balancing account at zero balance. 

"2. … the transmission system operators shall use an operational balancing account. The 
transmission system operator in control of the measurement equipment shall recalculate 
the  operational  balancing  account  with  validated  quantities  and  communicate  it  to  the 
adjacent transmission system operator(s).  

3. Where an operational balancing account applies:  

(a)  the  steering  difference  shall  be  allocated  to  an  operational  balancing  account 
of the adjacent transmission system operators and the allocations to be provided 
by each adjacent transmission system operator to their respective network users 
shall be equal to the confirmed quantities;  

(b)  the  adjacent  transmission  system  operators  shall  maintain  an  operational 
balancing account balance that is as close to zero as possible;  

(c)  the  operational  balancing  account  limits  shall  take  into  account  specific 
interconnected 
characteristics  of  each 
transmission networks..." [INT NC Article 9] 

interconnection  point  and/or 

the 

15 

2.8.1.6  Communication procedure in case of exceptional event 

INT NC defines the minimum information content for TSOs that has to be communicated 
to network users and adjacent TSOs in case of an exceptional event. 

"1.  The  adjacent  transmission  system  operators  shall  ensure  that  communication 
procedures … in cases of exceptional events are established…  

2. The transmission system operator affected by an exceptional event shall be required, 
as  a  minimum,  to  inform  its  network  users  with  respect  to  point  (b)  and  (c)  of  this 
paragraph  if  there  is  a  potential  impact  on  their  confirmed  quantities  and  the  adjacent 
transmission system operator(s) with respect to point (a) and (c) of this paragraph of the 
occurrence of such exceptional event and to provide all necessary information about:  

(a)  the  possible  impact  on  the  quantities  and  quality  of  gas  that  can  be 
transported through the interconnection point;  

(b) the possible impact on the confirmed quantities for network users active at the 
concerned interconnection point(s);  

(c) the expected and actual end of the exceptional event." [INT NC Article 10] 

Default rule: 

"…Unless  otherwise  agreed,  the  communication  between  the  involved  transmission 
system  operators  shall  be  performed  by  oral  communication  in  English  for  information, 
followed by an electronic written confirmation." [INT NC Article 10(1)]  

2.8.1.7  Dispute settlement 

"1.  The  adjacent  transmission  system  operators  shall  endeavour  to  solve  amicably  any 
disputes ... The dispute settlement mechanism shall at least specify:  

(a) the applicable law; and  

(b)  the  court  of  jurisdiction  or  the  terms  and  conditions  of  the  appointment  of 
experts ..." [INT NC Article 11] 

Default rule: 

"2.  In  the  absence  of  agreement  on  the  dispute  settlement  mechanism,  Council 
Regulation  (EC)  No  44/2001  and  Regulation  (EC)  No  593/2008  of  the  European 
Parliament and of the Council shall apply." [INT NC Article 11] 

2.8.1.8  IA amendment  

"1. The adjacent transmission system operators shall establish a transparent and detailed 
amendment process of their interconnection agreement ..." [INT NC Article 12]  

Default rules: 

"2.  If  the  adjacent  transmission  system  operators  fail  to  reach  an  agreement  on  the 
amendment  process,  they  may  use  the  dispute  settlement  mechanisms  developed  in 
accordance with Article 11." [INT NC Article 12] 

2.8.1.9  Monitoring results 

The  quantitative  analysis  revealed  that  6  IPs  have  no  IA  and  another  7  IPs  have 
incomplete IAs. 

16 

Table 2. IPs with no IA  

Source: ACER (7) 

Table 3. IPs with incomplete IA 

Source: ACER (7) 

According  to  the  qualitative  analysis  the  examined  IAs  –  with  one  exception  –  were  in 
compliance with INT NC at 85%. 

2.9  Units 

The  use  of  different  units  by  adjacent  system  operators  brings  a  significant  amount  of 
uncertainty  into  the  everyday  operation  of  the  system,  ranging  from  nomination  to 
allocation including the development of a technical background to handle different units.   

Therefore INT NC makes explicit definitive statements for the most common units.  

17 

 
 
"1. Each transmission system operator shall use the common set of units defined in this 
Article  for  any  data  exchange  and  data  publication  related  to  Regulation  (EC)  No 
715/2009.  

2.  For  the  parameters  of  pressure,  temperature,  volume,  gross  calorific  value,  energy, 
and Wobbe-index the transmission system operators shall use:  

(a) pressure: bar  

(b) temperature: °C (degree Celsius)  

(c) volume: m3  

(d) gross calorific value (GCV): kWh/m3  

(e) energy: kWh (based on GCV)  

(f) Wobbe-index: kWh/m3 (based on GCV)" [INT NC Article 13]  

As  indicated  previously  the  rules  are  meant  to  be  minimising  the  burden  imposed  on 
TSOs, so as long as units obviously do not hinder the creation of common market there is 
no need to change them. 

"3. In cases where one Member State is connected to only one other Member State, the 
adjacent  transmission  system  operators  and  the  parties  they  communicate  with  may 
agree to continue to use other reference conditions for data exchange ..." [INT NC Article 
13]  

2.10  Gas quality and Odourisation 

  Gas quality 

With regards to gas quality the task was to find the balance between  

a)  letting natural gas into the transmission system from a wide variety of sources that 
would be beneficial from both an increased competition and security of supply point 
of view and  

b)  constraining the acceptable gas composition for system integrity and safety. 

According  to  the  Impact  Assessment  "no  direct  EU-wide  technical  barrier  to  trade  has 
been  observed"  however  the  future  change  in  "flow  patterns"  necessitates  common 
actions in the area of gas quality. Also the phasing-out of low calorific value gas (L-gas) 
and the spread of biogas will need additional efforts in harmonisation. 

"The  following  local  issues  related  to  Gas  Quality  will  deserve  continuous  regulatory 
oversight in the coming years: 

a. Countries where L-gas is used may face temporary problems in the context of 
the phasing out of L-gas; 

b.  While  biogas  is  currently  used  locally,  its  increase  in  the  domestic  production 
may trigger cross-border impacts; 

c. Issues regarding the Wobbe index are likely to re-enter the EU debate and will require 
consumers  and  producers  better  to  coordinate  and  agree  on  a  common  position  in  the 
future." (7) 

Dealing with different gas qualities is one of the most cost sensitive issue in the area of 
interoperability,  so  INT  NC  offers  both  a  time  period  and  several  options  to  tackle  with 
any barrier to a common market:  

"2.  Where  a  restriction  to  cross-border  trade  due  to  gas  quality  differences  cannot  be 
avoided  by  the  concerned  transmission  system  operators  and  is  recognised  by  the 
national  regulatory  authorities,  those  authorities  may  require  the  transmission  system 

18 

operators  to  perform,  within  12  months,  the  actions  referred  to  in  points  (a)  to  (e)  in 
sequence:  

(a)  cooperate  and  develop  technically  feasible  options,  without  changing  the  gas 
quality specifications, which may include flow commitments and gas treatment, in 
order to remove the recognised restriction;  

(b)  jointly  carry  out  a  cost  benefit  analysis  on  the  technically  feasible  options  to 
define  economically  efficient solutions  which shall specify the breakdown of costs 
and benefits among the categories of affected parties;  

(c) produce an estimate of the implementation time for each potential option;  

(d)  conduct  a  public  consultation  on  identified  feasible  solutions  and  take  into 
consideration the results of the consultation;  

(e)  submit  a  joint  proposal  for  removing  the  recognised  restriction,  including  the 
timeframe  for  implementation,  based  on  the  cost  benefit  analysis  and  results  of 
the  public  consultation  to  their  respective  national  regulatory  authorities  for 
approval and to the other competent national authorities of each involved Member 
State for information." [INT NC Article 15]   

INT NC deals with variations in gas quality in two different time periods. Short-term 
quality fluctuations call for appropriate information supply for the parties that can be 
"adversely affected by gas quality changes". 

Long-term changes serve more the purpose of being prepared for new sources of natural 
gas. The task of forecasting gas quality on a long term is delegated to ENTSOG. 

"1. ENTSOG shall publish every two years a long-term gas quality monitoring outlook for 
transmission systems in order to identify the potential trends of gas quality parameters 
and respective potential variability within the next 10 years. The first long-term gas 
quality monitoring outlook shall be published along with the Ten-Year Network 
Development Plan of 2017.  

… 

3.The long-term gas quality monitoring outlook shall cover at least the Wobbe-index and 
gross calorific value. Additional gas quality parameters may be included … 

4.The long-term gas quality monitoring outlook shall identify potential new supply 
sources from a gas quality perspective.  

5. In order to define the reference values of gas quality parameters for the respective 
supply sources to be used in the outlook, an analysis of the previous years shall be 
carried out. …  

6.For every gas quality parameter considered and every region, the analysis shall result 
in a range within which the parameter is likely to evolve.  

7. The long-term gas quality monitoring outlook shall be consistent and aligned with the 
ENTSOG Union-wide Ten-Year Network Development Plan under preparation at the same 
time. …" [INT NC Article 18]   

With regards to short term fluctuations in gas quality the publication of Wobbe Index and 
Gross Calorific Value has been examined: 

Table 4. Wobbe Index 

Source: ACER (7) 

19 

 
  Odourisation 

Natural  gas  is  an  odourless  and  colourless  gas  which  becomes  explosive  at  a  certain 
concentration. For safety reasons an odour needs to be added that has to be distinctive 
and easily detectable on the one hand and shall not change the main properties of gas on 
the other hand. From a compatibility point of view, receiving odourised gas is usually the 
problem that system operators and system users need to tackle. 

Just  as  in  case  of  gas  quality,  INT  NC  offers  both  a  time  period  and  several  options  to 
tackle with any issues.  

"1. Where a restriction to cross-border trade due to differences in odourisation practices 
cannot  be  avoided  …  the  authorities  may  require  the  concerned  transmission  system 
operators  to  reach  an  agreement  within  six  months,  which  may  include  swapping  and 
flow commitments, to solve any restriction recognised. … 

2.  Where  no  agreement  can  be  reached  …  or  where  the  national  authorities  agree  that 
the proposed agreement by the concerned adjacent transmission system operators is not 
sufficiently  effective  to  remove  the  restriction,  the  concerned  transmission  system 
operators, in cooperation with national authorities, shall, within the following 12 months, 
define a detailed plan … to remove a recognised restriction ...  

3.  For  the  purpose  of  fulfilling  the  obligations  under  paragraph  2,  the  concerned 
transmission system operators shall in sequence:  

(a) develop options to remove the restriction by identifying and assessing:  

(i) a conversion towards cross-border physical flow of non-odourised gas;  

(ii)  the  potential  physical  flow  of  odourised  gas  into  the  non-odourised 
transmission  network  or  part  thereof  and  interconnected  downstream 
systems;  

(iii) an acceptable level of odourant for cross-border physical gas flow.  

(b)  jointly  carry  out  a  cost-benefit  analysis  on  the  technically  feasible  options  to 
define economically efficient solutions. That analysis shall:  

(i) take into account the level of safety;  

(ii) include information on projected volumes of gas to be transported and 
details of costs of necessary infrastructure investments;  

(iii) specify the breakdown of costs and benefits between the categories of 
affected parties;  

(c) produce an estimate of the implementation time for each potential option;  

(d)  conduct  a  public  consultation  and  take  into  consideration  the  results  of  such 
consultation;  

(e)  submit  the  feasible  solutions  including  the  cost  recovery  mechanism  and 
implementation  timing  to  the  national  authorities  for  approval."  [INT  NC  Article 
19]   

Default rule: 

"4.  If  the  national  authorities  do  not  approve  any  solution  …  or  if  the  concerned 
transmission  system  operators  fail  to  propose  a  solution  …,  a  shift  towards  the  cross-
border physical flow of non-odourised gas shall be implemented …" [INT NC Article 19]   

2.11  Data Exchange 

As  ACER  points  out  the  followings  are  necessary  to  be  dealt  with  for  an  efficient  data 
exchange. 

20 

"In order to possibly communicate, two parties must agree on a common standard, 
including: 

• a format, supporting the information; 

• a communication channel, via which information will be exchanged; 

•  a  communication  protocol,  codifying  possible  interactions  between  the  two 
parties." (6) 

According  to  the  cornerstones  above,  INT  NC  sets  the  types  of  data  exchange  and  the 
solutions for that (protocol, format and network).   

"1. Depending on the data exchange requirements …, one or more of the following types 
of data exchange may be implemented and used:  

(a)  document-based  data  exchange:  the  data  is  wrapped  into  a  file  and 
automatically exchanged between the respective IT systems;  

(b)  integrated  data  exchange:  the  data  is  exchanged  between  two  applications 
directly on the respective IT systems;  

(c) interactive data exchange: the data is exchanged interactively through a web 
application via a browser.  

2. The common data exchange solutions shall comprise the protocol, the data format and 
the network. The following common data exchange solutions shall be used for each of the 
types of data exchange listed in paragraph 1…" [INT NC Article 21] 

Naturally, in order to avoid unjustifiable costs the requirement of a  CBA also appears in 
INT NC.    

"3.  Where  a  potential  need  to  change  the  common  data  exchange  solution  is  identified, 
ENTSOG,  on  its  own  initiative  or  on  the  request  of  ACER,  should  evaluate  relevant 
technical  solutions  and  produce  a  cost-benefit  analysis  of  the  potential  change(s)  that 
would  be  needed  including  the  analysis  of  the  reasons  that  make  a  technological 
evolutional step necessary." [INT NC Article 21]    

INT NC delegates the responsibility for the security and availability of the data exchange 
system to the TSO and its counterparty. 

"1.  Each  transmission  system  operator  and  each  counterparty  shall  be  responsible  for 
ensuring that the appropriate security measures are undertaken. In particular, they shall: 

(a) secure the communication chain …;  

(b)  implement  appropriate  security  measures  in  order  to  prevent  unauthorised 
access of their IT infrastructure;  

(c) notify the other parties it communicates with, without delay, in regard to any 
unauthorised access which has or may have occurred on his own system.  

2. Each transmission system operator shall be responsible for ensuring the availability of 
its own system and shall:  

(a) take appropriate measures to prevent that a single point of failure causes an 
unavailability of the data exchange system…;  

… 

(c)  keep  the  downtime  …  to  a  minimum  and  shall  inform  its  counterparties  in  a 
timely manner, prior to the planned unavailability." [INT NC Article 22]    

Besides a set of rules concerning data security and availability  INT NC requires ENTSOG 
to  develop  a  common  network  operation  tool  (CNOT)  for  further  harmonisation  of  data 
exchange. 

21 

"…  ENTSOG  shall  develop  a  common  network  operation  tool  ...  A  common  network 
operation  tool  shall  specify  the  common  data  exchange  solution  relevant  for  the 
respective  data  exchange  requirement.  A  common  network  operation  tool  may  also 
include  business  requirement  specifications,  release  management  and  implementation 
guidelines. ..." [INT NC Article 24]    

ENTSOG  has  published  the  Common  Network  Operational  Tools  (CNOT)  in  order  to  set 
the standards for data exchange. The results of the ACER survey are as follows: 

Table 5. CNOT implementation status 

Source: ACER (7) 

22 

 
3  Congestion Management Procedures in Gas Transmission 

Systems 

3.1  Legislation 

The  Congestion  Management  Procedures  are  included  in  Annex  I,  point  2.2  (Congestion 
management  procedures  in  the  event  of  contractual  congestion)  of  Regulation  EC  No 
715/2009 (9) which was approved  on 13 July 2009 and is applicable since 3 September 
2009.  Two  amendments  relevant  to  the  CMP  were  decided  afterwards,  one  in  2012  (10) 
with which the entire point 2.2 of Annex I was replaced, and one in 2015 (11) with which 
point  2.2.1(2)  was  replaced.  A  consolidated  version  of  Regulation  EC  No  715/2009  was 
issued in 2015 (12).  

The following deadlines are specified in the Regulation: 

—  1  October  2013:  as  of  when  measures  provided  for  in  points  2.2.2,  2.2.4  and  2.2.5 

shall be implemented. 

—  1 July 2016: as of when points 2.2.3(1) and 2.2.3(5) shall apply. 

Four schemes are specified: 

—  Oversubscription and buy-back (OSBB) 

—  Firm day-ahead use-it-or-lose-it (FDA UIOLI) 

—  Surrender of contracted capacity 

—  Long-term use-it-or-lose-it (LT UIOLI) 

In  addition  to  the  Regulation,  the  European  Commission  issued  in  2014  a  working 
document  that  provides  guidance  on  best  practices  for  CMP  (13).  The  guidance  is 
summarised in paragraph 3.4. 

3.2  Principles 

TSOs  shall 
procedures at IPs, based on the following principles: 

implement  non-discriminatory 

transparent  congestion  management 

—  In  the  event  of  contractual  congestion,  TSOs  shall  offer  unused  capacity  on  the 

primary market at least on a day-ahead basis or interruptible basis 

—  Users can resell or sublet their unused capacity on the secondary market 

In  the  event  of  physical  congestion,  non-discriminatory  and  transparent  capacity 
allocation mechanisms shall be applied by the TSOs. 

(9)   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 and repealing Regulation (EC) No 1775/2005 
(https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX%3A32009R0715). 

(10)  2012/490/EU:  Commission  Decision  of  24  August  2012  on  amending  Annex  I  to  Regulation  (EC)  No 
715/2009  of  the  European  Parliament  and  of  the  Council  on  conditions  for  access  to  the  natural  gas 
transmission networks  
(https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012D0490). 

(11)  Commission Decision (EU) 2015/715 of 30 April 2015 amending Annex I to Regulation (EC) No 715/2009 of 
the  European  Parliament  and  of  the  Council  on  conditions  for  access  to  the  natural  gas  transmission 
networks 
(https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32015D0715). 

(12)  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 and repealing Regulation (EC) No 1775/2005 
(https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:02009R0715-20150525). 

(13)  COMMISSION  STAFF  WORKING  DOCUMENT,  Guidance  on  best  practices  for  congestion  management 

procedures in natural gas transmission networks, Brussels, 11.7.2014, SWD(2014) 250 final 
(http://ec.europa.eu/energy/sites/ener/files/documents/20140711_guidance_congestion_management_ng
tn.pdf). 

23 

                                           
 
 
 
For LNG and storage facilities: 

—  Unused  LNG  and  storage  capacity  shall  be  offered  to  the  primary  market  without 

delay 

—  For storage facilities, unused capacity shall be offered to the primary market at least 

on a day-ahead and interruptible basis 

—  LNG and storage facility users can resell or sublet their unused capacity on secondary 

market 

3.3  Overview of CMP  

  General provisions 

The  CMP  applies  to  IPs,  physical  or  virtual,  subject  to  booking  procedures  by  users.  It 
may also apply to IPs with third countries, if the NRA decides to do so. 

CMP  does  not  apply  exit/entry  points  to  end  consumers,  distribution  networks,  LNG 
terminals, production facilities and storage facilities. 

ACER  publishes  a  monitoring  report  by  1  June  each  year,  starting  from  2015,  covering 
firm  capacity  in  the  preceding  year,  taking  into  consideration  secondary  markets  and 
interruptible capacity. 

Additional capacity from the application of CMP is offered during regular allocation. 

  Capacity increase through oversubscription and buy-back scheme 

The OSBB scheme is proposed by TSOs to NRAs, and ultimately approved by the relevant 
NRAs.  It  envisages  that  additional  capacity,  capacity  offered  in  addition  to  the  technical 
capacity, offered on firm basis. 

The OSBB is incentive based, shall take into consideration technical conditions, and shall 
reflect  the  risk  of  offering  additional  capacity.  A  dynamic  approach  to  recalculation  of 
technical and additional capacity is to be used, with revenues/costs shared between TSOs 
and users. 

Capacity  from  FDA  UIOLI  and  LT  UIOLI,  and  surrendered  capacity,  are  allocated  before 
any additional capacity. 

The TSO shall use statistical scenarios for the likely amount of physically unused capacity 
and  take  into  account  a  risk  profile  for  offering  additional  capacity  so  that  there  is  no 
excessive buy-back obligation. 

A  market-based  buy-back  procedure  to  maintain  system  integrity  shall  be  used.  Before 
initiating the buy-back procedure, the TSO shall check whether alternative technical and 
commercial measures are more cost-efficient. 

Relevant  data,  estimates  and  models  for  the  scheme  are  submitted  to  the  NRA  for 
assessment. 

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

The FDA UIOLI applies if, based on the annual ACER report, demand exceeds offer, at the 
reserve price when auctions are used, during the capacity allocation process in the year 
covered by the report for products for use in either that year or in one of the subsequent 
two years: 

—  For at least three firm capacity products with duration of one month, or 

—  For at least two firm capacity products with duration of one quarter, or 

—  For at last one firm capacity product with duration of one year or more, or 

—  No firm capacity product with duration of one month or more has been offered 

24 

If the situation is unlikely to reoccur in the following three years, the NRA may terminate 
the FDA UIOLI mechanism. 

For  users  that  hold  more  than  10%  of  the  average  technical  capacity  in  the  preceding 
year: 

—  Firm  renomination  is  permitted  up  to  90%  and  down  to  10%  of  the  contracted 

capacity 

—  If the nomination is over 80%, half the non-nominated volume may be renominated 

upwards 

—  If the nomination is less than 20%, half the nominated volume may be renominated 

downwards 

The  original holder can  renominate the  restricted part  of its contracted firm capacity on 
an interruptible basis. 

Where  FDA  UIOLI  is  applied,  and  after  an  evaluation  of  the  relation  between  the  OSBB 
scheme  and  the  FDA  UIOLI  mechanism  is  performed  by  the  NRA,  the  NRA  may  decide 
not to apply the OSBB. 

The  NRAs  of  adjacent  member  states  are  to  be  consulted  before  the  FDA  UIOLI  is 
adopted. 

  Surrender of contracted capacity  

TSOs  shall  accept  any  surrender  of  firm  capacity.  However,  capacity  products  with 
duration of one day or shorter are excluded. 

User  retains  rights  and  obligations  until  capacity  is  reallocated.  The  TSO  notifies  user 
immediately for the reallocation. 

NRA approves terms and conditions when several users surrender their capacity. 

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

According  to  the  LT  UIOLI  mechanism,  TSOs  are  required  to  partially  or  fully  withdraw 
systematically  underutilised  contracted  capacity  when  a  user  has  not  sold  or  offered 
under reasonable conditions unused capacity and when users request firm capacity. 

Contracted capacity is considered systematically underutilised when: 

—  User  uses  less  than  80%  on  average  both  from  01/04  until  30/09  and  from  01/10 

until 31/03 with a contract of more than one year, without justification, or 

—  User nominates close to 100% and renominates downwards to circumvent FDA UIOLI 

rules 

The application of FDA UIOLI shall not be regarded as justification to prevent LT UIOLI. 

User loses all or partial capacity for a given period or the remained of contract but retains 
rights and obligations until capacity is reallocated. 

The TSO provides to NRA data to monitor the extent to which contracted capacities with 
duration  of  more  than  one  year,  or  recurring  quarters  covering  at  least  two  years,  are 
used. 

3.4  Guidance on best practices for CMP 

  Oversubscription and buy-back scheme 

The OSBB scheme can be regarded as the basic instrument for congestion management. 
The  TSO  determines  the  amount  of  capacity  likely  to  remain  unused  by  the  capacity 
contract  holders.  Naturally,  the  OSBB  cannot  be  applied  in  the  case  of  physical 
congestion. 

25 

The OSBB shall be applied by all TSOs unless the relevant NRA decides not to apply the 
OSBB, and, thus, applies the FDA UIOLI. 

It is a simple mechanism is case of low booking levels, and can be used as a preventative 
system, fulfilling the objectives of CMP. More sophisticated analysis required for meshed 
and  complex  networks  and  high  booking  levels.  A  cost-benefit  analysis  will  be  required 
for  risk  and  reward.  If  the  offer  of  additional  capacity  is  too  complex,  the  NRA  should 
apply the FDA UIOLI instead. 

There  are  no  rules  or  recommendations  on  the  type  of  products  the  TSO  can  offer,  but 
there  should  be  a  balance  between  additional  capacity  and  the  obligation  to  maximise 
capacity. Naturally, shorter term products will be offered first while longer term products 
will be offered as the system becomes more sophisticated. 

NRA should ensure that the TSO is incentivised so that the TSO offers additional capacity. 
Additional capacity shall always be of firm nature 

Balance  has  to  be  achieved  between  over-remuneration  and  heavy  losses  in  case 
nominated  flows  cannot  be  realised.  As  such,  appropriate  baseline  capacity  needs  to  be 
defined to achieve balance. The relevant methodology should be reviewed regularly. 

There  should  be  no  distinction  between  technical  firm  capacity  and  oversubscribed  firm 
capacity. 

The users  shall decide whether  or not they want to sell their rights back to the TSO.  In 
the  opposite  case,  if  the  TSO  actually  decided,  capacity  would  become  in  effect 
interruptible. The users shall receive either financial compensation or gas at destination. 

The  TSO  should  check  for  the  most  cost-efficient  measure  to  solve  congestion  (e.g. 
agreements  with  adjacent  TSOs,  buy  gas  at  market  hub  and  sell  upstream)  to  avoid 
situations where users are not willing to sell capacity or they want to sell at a very high 
price. 

If an IP is connecting liquid markets, the buy-back price is unlikely to be higher than the 
price differential. This implicit cap may be made explicit by the NRA, so that the TSO risk 
is managed. 

Pro  rata  curtailment  to  maintain  system  integrity  is  only  acceptable  as  a  last  resort 
measure, when no alternatives exist or when a cap is applied. 

If  the  risk  for  additional  capacity  is  too  high,  or  the  number  of  users  is  limited  and 
market is not liquid, the OSBB may not be appropriate. In this case, the FDA UIOLI may 
be more appropriate. 

NRAs may  set up an overall maximum "pot" capping TSO incentive revenue and losses. 
Clear boundaries for profit and loss sharing between TSO and users should be defined. 

Users  should  not  be  able  to  renominate  upwards  if  buy-back  is  initiated.  If  this  is  too 
restrictive, buy-back could run after the renomination cycle. Buy-back should be initiated 
closer to delivery (not on the day-ahead) to minimise opportunities for gaming by users. 

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

The FDA UIOLI is restrictive in the way capacity rights can be used. It was meant to be a 
fall-back measure to the OSBB if the OSBB deemed not to be effective by 1 July 2016. 

The OSBB and the FDA UIOLI are alternatives. 

It  is  important  that  the  both  sides  of  IPs  use  the  same  measures.  The  lesser  rule  shall 
apply  otherwise:  in  case  of  different  processed  quantities  at  either  side  of  an  IP,  the 
confirmed  quantity  will  be  equal  to  the  lower  of  the  two  processed  quantities.  The 
problem is more pronounced with bundled capacity. Compatibility between schemes can 
be  achieved  with  either  the  FDA  UIOLI  without  downward  10%  restriction  or  the  OSBB 
with 10% restriction. 

26 

For compatibility, the following could be applied: 

—  The FDA UIOLI has precedence if conditions of 2.2.3.1 are fulfilled, if not fulfilled the 

OSBB has precedence 

—  If the FDA UIOLI is applied after 01/07/2016 according to 2.2.3.1, the FDA UIOLI has 

precedence over the OSBB 

  Capacity surrender 

This  is  an  alternative  to  user's  right  to  offer  capacity  on  the  secondary  market.  It  is 
successful when part or all of the capacity offered is reallocated. There is no incentive for 
users  so  that  they  don't  book  capacity  only  to  hand  it  back  to  the  TSO.  No  benefit  for 
users from sale of their capacity (e.g. share of auction premium). 

Surrendered capacity is allocated after available capacity. Surrendered bundled capacity 
is reallocated in bundled form, if there is demand. 

The  main  difference  with  secondary  markets  is  the  fact  that  surrendered  capacity  gives 
the  TSO  the  possibility  to  use  the  capacity  as  it  wants,  and  the  capacity  can  be  rolled-
over. 

The user can withdraw the surrendered capacity, taking into consideration the timeframe 
of the roll-over and CAM NC auction calendar. 

Surrendered  capacity  is  offered  in  the  order  it  has  been  offered  to  the  TSO  (timestamp 
approach). 

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

This mechanism is used to deter long term capacity hoarding. Either NRAs or TSOs may 
decide  ultimately  on  the  withdrawal  of  capacity.  TSOs  provide  information  to  NRAs  on 
capacity usage. A monitoring framework is essential.  

To  avoid  withdrawal  of  capacity,  network  users  should  offer  the  unused  capacity  under 
reasonable conditions, i.e. secondary markets for reasonable price or surrendered to the 
TSO. 

The  LT  UIOLI  takes  effect  only  if  other  users  demand  capacity.  The  TSO  remains  cost-
neutral throughout. 

Underutilisation  is  defined  as  less  than  average  80%.  The  LT  UIOLI  refers  to  contracts 
with explicit duration of more than a year or series of one year contracts. 

The NRA is best placed to determine whether full or partial withdrawal is required. 

3.5  Status of Implementation 

  ACER 

ACER  has  a  legal  obligation  to  publish  a  yearly  report  on  contractual  congestion  at  IPs. 
The latest report was published on 31 May 2018 (14). It covers 2017. 

17  (or  about  7%)  of  the  262  IP  sides  in  the  scope  of  the  CMP  were  contractually 
congested.  For  other  72  IP  sides  Gas  Year  2018/19  products  were  not  offered  in  2017 
(not considered congested but formally congested). There was no conclusive evidence on 
whether  contractual  congestion  increased  or  decreased  in  2017.  Figure  1  provides  the 
distribution of IP sides based on the status of contractual congestion. 

(14)  ACER Annual Report on Contractual Congestion at Interconnection Points - 2017 

(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/Congestion%20Report%205th
%20ed.pdf). 

27 

                                           
 
The  FDA  UIOLI  was  already  applied  at  8  out  of  the  17  IP  sides  that  were  contractually 
congested.  For  the  remaining  9  IP  sides,  FDA  UIOLI  is  to  be  implemented,  unless 
congestion is unlikely to occur in the next three years. 

Figure 1: Contractual congestion 

Source: ACER (14) 

Overall, contractual congestion was found in the following locations (Figure 2 and Figure 
3): 

—  German borders (with Belgium, Switzerland, Austria) + inside Germany 

—  Bulgaria-Greece 

—  Romania-Bulgaria 

—  Italy-Austria (due to construction works) 

—  Inside France (zone merger in 2018) 

Figure 2: List of contractually congested IPs 

Source: ACER (14) 

28 

 
 
 
 
Figure 3: Map of contractually congested IPs 

Source: ACER (14) 

As shown in Figure 4, 11 out of the 17 contractually congested IP sides were due to non-
offer of firm products with duration of at least one month for use in 2017/2018. 6 out of 
the 17 contractually congested IP sides were signalled by auction premia.  

Figure 4: Reason for contractual congestion 

9  out  of  17  IP  sides  were  contractually  congested  in  the  2017  report,  10  of  those  were 
contractually congested in the 2016 report. 

Source: ACER (14) 

29 

 
 
Physical  congestion,  indicated  by  interruption  of  interruptible  capacity,  was  found  at  5 
contractually congested IP sides. CMP brought additional capacity offers at the borders of 
11 member states (were 7 in the previous report). 

No application of the LT UIOLI. 

The  OSBB  was  used  in  6  member  states  (were  3  in  the  previous  report).  Almost  all 
additional capacity was on the Dutch and the UK IP sides. 

Capacity surrender was used in 6 member states. The majority of additional capacity was 
in the Czech IP sides. 

  ENTSOG 

ENTSOG  monitors  and  analyses  the  implementation  of  the  CMP.  The  latest  report  was 
approved in April 2018 and published on 7 June 2018 (15). It covers 2017. 

The conclusions are: 

—  38 of 49 EU TSOs (45 ENTSOG members, 2 associated partners and 2 TSOs that are 
not  ENTSOG  members)  have  implemented  Capacity  Surrender,  LT  UIOLI,  and  OSBB 
or FDA UIOLI. 

—  1  TSO  of  which  the  NRA  has  not  approved  the  proposed  scheme  yet  (OSBB  - 

Hungary) 

—  1 TSO is expected to finish with implementation within 2018 (Romania) 

—  9  TSOs  have  derogations  or  have  no  IPs  (1  TSO  has  implemented  CMP  measures 

anyway) 

Overall, 47 of 49 TSOs are fully compliant with the CMP. 

ENTSOG captures the effect of CMP using two indicators: 

—  CMP.1: Additional capacity volumes made available through each CMP 

—  CMP.2: Share of capacity reallocated through CMP among total capacity reallocated 

The specifics of the two indicators are shown in Figure 5 and Figure 6. 

Figure 5: Indicator 1 (CMP.1) 

(15)  ENTSOG  Congestion  Management  Procedures  Guidelines  Implementation  and  Effect  Monitoring  Report  - 

2017 
(https://www.entsog.eu/public/uploads/files/publications/Implementation%20Monitoring/2018/cmp/entsog
_CMP_guidelines_I+EMR_2017_web.pdf). 

30 

 
                                           
 
Source: ENTSOG (15) 

Figure 6: Indicator 2 (CMP.2) 

Source: ENTSOG (15) 

The  TSOs  included  in  the  survey  are  those  with  one  or  more  IPs  rated  as  congested  in 
last year’s  contractual congestion report from  ACER (16). Results of CMP.1 are  shown in 
Figure 7 (BG/FR/DE/HU/ES/RO). 

Figure 7: Results for CMP.1 

Source: ENTSOG (15) 

(16)  ACER Annual Report on Contractual Congestion at Interconnection Points – 2016 

(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/ACER%202017%20Implemen
tation%20Monitoring%20Report%20on%20Contractual%20Congestion%20at%20Interconnection%20Point
s.pdf). 

31 

 
 
 
                                           
The FDA UIOLI is the only mechanism that released capacity. It is used by Germany and 
most  TSOs  with  congested  IPs.  However,  the  amount  actually  allocated  via  the  FDA 
UIOLI is very low either because capacity surrender and the secondary market provided 
the necessary capacity or there is no actual congestion. 

Results of CMP.2 are shown in Figure 8. 

Figure 8: Results for CMP.2 

Source: ENTSOG (15) 

Both CMP mechanisms and secondary markets  are well established. However, only 10% 
of  the  capacity  reallocated  is  reallocated  via  CMP  mechanisms.  The  secondary  markets 
are an important alternative to CMP mechanisms for network users. 

32 

 
 
References 

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 and repealing 
Regulation (EC) No 1775/2005 (https://eur-lex.europa.eu/legal-
content/EN/ALL/?uri=CELEX%3A32009R0715) 

2012/490/EU: Commission Decision of 24 August 2012 on amending Annex I to 
Regulation (EC) No 715/2009 of the European Parliament and of the Council on 
conditions for access to the natural gas transmission networks (https://eur-
lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012D0490) 

Commission Decision (EU) 2015/715 of 30 April 2015 amending Annex I to Regulation 
(EC) No 715/2009 of the European Parliament and of the Council on conditions for access 
to the natural gas transmission networks (https://eur-lex.europa.eu/legal-
content/EN/TXT/?uri=CELEX:32015D0715) 

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 and repealing 
Regulation (EC) No 1775/2005 (https://eur-lex.europa.eu/legal-
content/EN/ALL/?uri=CELEX:02009R0715-20150525) 

COMMISSION STAFF WORKING DOCUMENT, Guidance on best practices for congestion 
management procedures in natural gas transmission networks, Brussels, 11.7.2014, 
SWD(2014) 250 final 
(http://ec.europa.eu/energy/sites/ener/files/documents/20140711_guidance_congestion
_management_ngtn.pdf) 

ACER Annual Report on Contractual Congestion at Interconnection Points – 2017 
(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/Congestion
%20Report%205th%20ed.pdf) 

ENTSOG Congestion Management Procedures Guidelines Implementation and Effect 
Monitoring Report – 2017 
(https://www.entsog.eu/public/uploads/files/publications/Implementation%20Monitoring
/2018/cmp/entsog_CMP_guidelines_I+EMR_2017_web.pdf) 

ACER Annual Report on Contractual Congestion at Interconnection Points – 2016 
(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/ACER%202
017%20Implementation%20Monitoring%20Report%20on%20Contractual%20Congestion
%20at%20Interconnection%20Points.pdf). 

Commission Regulation (EU) No 2015 / 703 of 30 April 2015 establishing a network code 
on interoperability and data exchange rules (https://eur-lex.europa.eu/legal-
content/EN/TXT/?uri=OJ:JOL_2015_113_R_0003) 

COMMISSION REGULATION (EU) 2017/459 of 16 March 2017 establishing a network 
code on capacity allocation mechanisms in gas transmission systems and repealing 
Regulation (EU) No 984/2013 (Text with EEA relevance. ) (https://eur-
lex.europa.eu/legal-content/en/TXT/?uri=CELEX:32017R0459) 

Initial Impact Assessment accompanying the document Framework Guidelines on 
Interoperability and Data Exchange Rules for European Gas Transmission Networks 
(ACER 2012) 
(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Framework_Guidelines/
Related%20documents/Initial%20Impact%20Assessment%20(IIA)_ENTSOG.pdf) 

Framework Guidelines on Interoperability and Data Exchange Rules for European Gas 
Transmission Networks (ACER 2012) 
(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Framework_Guidelines/
Related%20documents/FG%20on%20Interoperability%20and%20Data%20Exchange%2
0Rules%20for%20European%20Gas%20Transmission%20Networks.pdf) 

33 

First ACER Implementation Monitoring Report of the Network Code on Interoperability 
and Data Exchange 
(https://acer.europa.eu/Official_documents/Acts_of_the_Agency/Publication/First%20AC
ER%20Implementation%20Monitoring%20Report%20of%20the%20Network%20Code%
20on%20Interoperability%20and%20Data%20Exchange.pdf) 

34 

List of abbreviations and definitions 

ACER 

CAM 

CBA 

CMP 

CNOT 

EC 

Agency for the Cooperation of Energy Regulators 

Capacity Allocation Mechanisms 

Cost/Benefit Analysis 

Congestion Management Procedures 

Common Network Operation Tool 

European Commission 

ENTSOG  

European Network of Transmission System Operators for Gas 

EU 

European Union 

FDA UIOLI  

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

GCV 

GTM  

IA 

IP 

LNG  

Gross Calorific Value 

Gas Target Model 

Interconnection Agreement 

Interconnection Point 

Liquefied Natural Gas 

LT UIOLI  

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

MS 

NC 

NRA 

OSBB 

TSO 

Member State 

Network Code 

National Regulatory Authority 

Oversubscription and buy-back 

Transmission System Operator  

TYNDP   

Ten Year Network Development Plan 

35 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
List of figures 

Figure 1: Contractual congestion ...........................................................................28 

Figure 2: List of contractually congested IPs ...........................................................28 

Figure 3: Map of contractually congested IPs ..........................................................29 

Figure 4: Reason for contractual congestion ...........................................................29 

Figure 5: Indicator 1 (CMP.1) ...............................................................................30 

Figure 6: Indicator 2 (CMP.2) ...............................................................................31 

Figure 7: Results for CMP.1 ..................................................................................31 

Figure 8: Results for CMP.2 ..................................................................................32 

36 

 
List of tables 

Table 1. Regulated areas, options and decisions ....................................................... 7 

Table 2. IPs with no IA .........................................................................................17 

Table 3. IPs with incomplete IA .............................................................................17 

Table 4. Wobbe Index ..........................................................................................19 

Table 5. CNOT implementation status ....................................................................22 

37 

 
 
 
Annexes 

ANNEX I. – ENTSOG IA Template 

38 

 
 
39 

 
 
 
ANNEX II. – ENTSOG CNOT on Common Data Exchange Solutions 

40 

 
 
41 

 
 
ANNEX III. – ACER IA Survey 

42 

 
 
ANNEX IV. – ENTSOG IA Survey 

43 

 
 
44 

 
45 

 
 
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