Support our Current Electricity
and Focus on the Future of Electricity

Organization for Cross-regional Coordination of Transmission Operators,JAPAN
6-2-15, Toyosu, Koto-ku, Tokyo, 135-0061, Japan
www.occto.or.jp

Organization for Cross-regional Coordination ofTransmission Operators, JAPANPublished in April 2021

The Organization for Cross-Regional Coordination of Transmission Operators(OCCTO) was established in April 2015 and has been performing its duties inaccordance with the purposes for which it was established: namely, to maintain astable supply of electricity and render power supply systems as efﬁcient as possible from a neutral and impartial position.
I am cognizant of the weight of what my position entails as I take over as thepresident of this organization.
With the tightening of electricity supply and demand in last winter, we continue to be beset by circumstances that call on us to fulﬁll our roles as an organization to an even greater extent than ever before. We should revisit the purposes
for which we were established and work even harder to fulﬁll them.
In addition, accommodating the growing adoption of renewable energy is also
an urgent matter to be addressed. As well as dealing with balancing capacity
matters and other issues, we have taken on new operations related to the Act on
Renewable Energy Special Measures in accordance with the Act for Establishing
Energy Supply Resilience, which was enacted in June 2020. We will focus on
these operations while keeping the governmentʼs goals in mind.
All board and staff members of this organization will strive further to support
Japanʼs electric power system today, fulﬁll our important roles for tomorrow, andlive up to expectations.
I respectfully ask for your continued support and encouragement.

President

April 2021

Tsutomu Oyama

Roles of OCCTO

Roles of OCCTO

Support our Current Electri cityand Focus on the Future of Electricity
Efforts so far and recent efforts of OCCTO
Secure short-term to mid- tolong-term stable supply

Streamline the fair usage environment of electricity
systems in Japan by formulating guidelines on transmission/distribution operations, accepting system impact
studies, and managing use of interconnection lines.

Process of Electricity System Reform

Studying, undertaking a detailed
design of, and operating
the capacity market
Studying, undertaking a detailed
design of the balancing market

Recent effort

Efﬁcient use oftransmission/distribution
facilities
Review “Connect and Manage”

We have worked across three steps with a view to reforming the electricity supply system.
Three Goals① Securing Stable Electricity Supply② Suppressing Electricity Rates to the Maximum Extent Possible③ Expanding Electricity Choices for Consumers and Business Opportunities

M onitor n ationw ide s upply- de m a nd condition s a n d
network conditions of power systems
Step 3 ▶ Ap ril

2016
Step 2 ▶ Ap ril

2015● Full liberalization of entry to the electricity retail business

Establishment of OCCTO

2020

Legal unbundling oftransmission/distribution sector● Introduction of functional licensing system

Role of OCCTO in the Electricity System Reform● Study at the council level● Draft and enforcement oflaws and regulations● Study at the council level● Draft and enforcement of laws and regulations● Study at boards, etc. from expert perspective● Formulate regulations and codes● Formulate Long-term Policy andElectricity
companies● Draft network facilities plan
● Implement network

access operation

Cross-regional Network Development Plan

After establishmentof OCCTO● Study network access operation

Electricity
companies● Draft network facilities plan
● Implement network access operation

New roles for OCCTO added through the enactment of the Act for
Establishing Energy Supply Resilience
The following operations were added as roles to be fulﬁlled by OCCTO through the enactment of the Act of Partial
Revision of the Electricity Business Act and Other Acts for Establishing Resilient and Sustainable Electricity Supply
Systems (in June 2020) (Act for Establishing Energy Supply Resilience). OCCTO will ensure that these operations arecarried out and will fulﬁll its new roles accordingly:●Check the contents of disaster coordination plans formulated by general transmission and distribution companies●Operate a mutual assistance system for disaster recovery costs●Formulate cross-regional network development plans, submit them to the Government, and grant subsidies under the renewable energy levy system to partially cover the costsof developing inter-regional interconnection lines as set forth in these plans●Grant subsidies related to the feed-in tariff (FIT) scheme for renewable energy●Grant premiums related to the feed-in premium (FIP) scheme● Manage the reserve fund for the disposition of solar panels and other hardware components

Organization framework, etc.

Government

Government

Monitor electricity supply-demand conditions as well as network conditions of power systems 24 hours a day, 365 days a year to grasp the wholecentrally on a nationwide scale. We centrally monitor the state of the
supply of and demand for electricity and the operations of the network
twenty-four hours a day, 365 days a year on a nationwide scale. By
instructing electric power companies to interchange power and increase
the supply of thermal power plants whenever the supply-demand situation worsens, we ensure the stable supply of electricity.

Supply-demand condition
Network operation

Step 1 ▶ Ap ril

Electricity network
usage environment

大山 力

Promote fair,equitable and efﬁcient use oftransmission/distribution
facilities

Secure supply/
balancing capacity

Stable electricity supply

In addition to aggregating electricity supply plansthat are annually submitted from all electricity
companies, OCCTO formulates Cross-regional
Network Long-term Policy and Development Plans tosecure not only short-term but also mid- to long-term
stable supply on a nationwide scale.

Recent effort

Electricity supply plans will be consolidated,
and a stable supply of electricity will be secured for the short,medium, and long terms.

Co n t r i b u te to e f ﬁ c i e n c y i m p r ove m e n t a n d a c t i v a t i o n o felectricity market
As electrical power production became separated from power distribution and transmission in 2020 and as renewable energy is increasingly
adopted, OCCTO has been investigating, undertaking a detailed designof, and operating new markets in which the value of electric power istraded in order to develop a framework for securing and harnessing the
supply and balancing capacity required for the stable supply of electricity on a medium- to long-term basis at the lowest possible cost.

Value to be traded (product)
Electric energy【kWh value】

Actual electricity generated

OCCTO formulated a long-term policy (Long-Term Policy on Cross-regional Network), which put together a course of action
related to the development and upgrading of cross-regional interconnection systems nationwide and announced this policy inMarch 2017. In addition, OCCTO formulated and announced a cross-regional network development plan pertaining to interconnection facilities linking Tokyo and Chubu in June 2016. In order to fulﬁll one of its new roles, which was added under the Act for
Establishing Energy Supply Resilience and which entails formulating Cross-regional Network Development Plans and submitting
them to the Government, OCCTO has been working on formulating a cross-regional network development plan pertaining tointerconnection facilities linking Hokkaido and Honshu and a cross-regional network development plan pertaining to interconnection lines linking the Tohoku region and Tokyo.
●Cross-regional Interconnection Network< Interconnection Lines and Bulk Transmission Lines in Each Area (Highest 2 Voltage Classes) >Trading market
Kitahon HVDC Link

Wholesale
electricity market

Supply capacity【kW value】

Generation capability

CapacitymarketBalancing capacity【 kW value】

Capability to balance
supply-demand in short-term

BalancingmarketHokuto Imabetsu DC Trunk LineH o k ka i d o a rea
Tohoku area

The full liberalization of the electricity industry and large-scale adoption of renewable energy threatens to lower the predictability of
returns on investments in power sources. The resulting shortfall in investments in power sources could lead to power shortages in the
future. The capacity market will increase the predictability of returns on investments in power sources by paying some of the costs
required for power sources in accordance with the value of the capability of power sources to generate electricity (supply capacity),
which in turn will help secure supply capacity and adjustment capacity on a medium- to long-term basis. OCCTO is investigating,undertaking a detailed design of, and operating the capacity market as a market manager.

(Temporary)
Cross-regional Interconnection
South Trunk Line
Soma Futaba Trunk Line

Hokuriku area
Shin Shinano Frequency Converter Station

Minami-Fukumitsu Linkage Station BTB

Setting a supply capacity that should
be secured on a nationwide scale

Determining generation companies
that will provide supply capacity

Tokyo area

Hida-Shinano DC Trunk Line

Kansai area

Echizen-Reinan LineD

Actual demandand supply period

E
F

Higashi-Shimizu Frequency Converter Station
Seiban-Higashi Okayama Line

Retail companies pay costs required
to secure kilowatt value (supply
capacity) through auctions.

Sakuma Frequency Converter Station

Honshi Interconnecting Line

Chugoku area

Generation companies receive
remuneration depending on thekilowatt value (supply capacity)
they offered.

Mie-Higashi Oumi Line

Kanmon Interconnecting Line

Chubu area

Sekigahara-Kita Oumi Line
Anan-Kihoku HVDC Link

▶ Settle payments in light of the state of the supply capacity being offered during the period in question.
▶ When shortage occurs, impose penalty on each company

Shikoku area

Power plant

As renewable energy becomes the primary power source, itwill be possible to more efﬁciently procure and operate thebalancing capacity that is needed to allow general transmission and distribution operators to provide a stable supply ofelectricity by realizing cross-regional procurement cross-regional operations in a balancing market. OCCTO is studying
and undertaking a detailed design of this market.

Substation

Kyushu area

Switching station
AC/DC converter
Frequency converter stations, interconnected facilities
500 kV transmission lines and DC interconnection lines
275 kV or under transmission lines
Currently under planning

Okinawa area

Organization framework, etc.

Studying and undertaking a detailed
design of a balancing market

Supply-demand condition
Network operation

Yamazaki-Chizu Line
Generation companies offer kilowatt
value (supply capacity) throughauctions.

Electricity network
usage environment

Studying, undertaking a detailed design of, and operating the capacity market

Before actual
demand and supply

Stable electricity supply

The electricity supply plans are plans in which the 10-year supply-demand forecast, development of power stations anddevelopment of transmission/distribution grids are aggregated. All electricity companies have an obligation tosubmit a supply plan to the Minister of Economy, Trade and Industry in accordance with the Electricity Business Act.
OCCTO grasps and evaluates centrally the supply-demand balance nationwide and in supply areas for short-, mid-, andlong-term by aggregating these plans. Furthermore, OCCTO secures a stable supply by generator procurement called“Generation Plant Bidding “ when necessary.

Fo r m u l a t e L o n g - t e r m Po l i c y a n d D e ve l o p m e n t P l a n f o rcross-regional net work , and take initiative in reinforcing
required facilities

Roles of OCCTO

Stable electricity supply

Secure Short -term to Mid -to Long - term Stable Supply

OCCTO formulated the Network Codes, a set of rules to be followed by transmission operators and users in accordance with
the Electricity Business Act and revises these guidelines where necessary in an effort to ensure the proper and smooth operations of consigned supply operations and operations pertaining to the transmission and distribution of electricity.

Against the background of progress in electricity liberalization and the Feed-in Tariff Scheme (FIT Scheme) of renewableenergy, power stations with variable renewable energy such as photovoltaic as well as projects to build new thermal
power stations are increasing and the needs of interconnection for new power sources are expanding.
In formulating a long-term policy on cross-regional network, OCCTO decided to aim to facilitate and render more
affordable use of the electric power network by maximizing the use of the existing network in light of these environmental
changes. To this end, OCCTO has been conducting“Probabilistic evaluation of power ﬂow”*1 and engaged in connect andmanage efforts (N-1 inter-tripping scheme and non-ﬁrm access connections). Further, we continue studying new network
operation rules such as re-dispatching method*2.
*1 Probabilistic evaluation of power ﬂow is a methodology to increase available transmission capacity by assumed power ﬂow given the actual situation and assessing network, such as byreviewing practical output based on historical data of variable renewable energy and by practical generator dispatches in accordance with demand (applied on April 2018)*2 Re-dispatching method is a methodology to manage congestion which general transmission and distribution company implement utilizing balancing capacity when it judges that congestion of
network occurs, or likely to occur, without specifying congested line.

Japanese Connect and Manage
N-1 Inter-Trip scheme

Reviewing the method by which interconnection lines are used
Considering the deliberation results of the System Review Working Group on Electricity and Gas Basic Policy
Subcommittee (3rd), as well as from the viewpoint of utilizing fair and equitable and efﬁcient use of interconnectionlines and developing a market environment, OCCTO changed the interconnection lines usage method to “implicit
auction ” in October 2018.

In Japan, from the viewpoint of network reliability, etc., power system development is conducted to secure stable andadequate transfer capacity even if an N-1 contingency (e.g. single line fault) occurs. N-1 Inter-trip scheme is a measure toutilize this capacity under no contingency situation by inter-tripping a generator when N-1 contingency occurs (curtailment of
the generator output immediately with the relay system).
The N-1 inter-tripping scheme began to be applied to new power sources to be connected to a special high-voltage network
in October 2018 (prior application). System design work is being carried out to enable the N-1 inter-tripping scheme to be
applicable to new power sources to be connected to the high-voltage network sometime during ﬁscal year 2022.

Stable electricity supply

Formulate rules for all electricity companies to comply

Make efforts to maximize utilization of existing network

Roles of OCCTOElectricity network usage environment

Promote Fair, Equitable andEfﬁcient Use of
Transmission/Distribution Facilities

Electricity network
usage environment

Mechanism before implicit auction

Implicit auction

Te r m i n a te a cce p ti n g i n te rco n n e c ti o n l i n e
After accumulating capacity allocation on a ﬁrst-come, ﬁrst served reservations on a ﬁrst-come, ﬁrst served basis andbasis, capacity is allocated to the day ahead market by utilizing allocate all capacity on interconnection lines to theavailable capacity at 10:00 a.m. of the previous day.
day ahead market in principle.

Accept system impact studies of generation facilities
OCCTO will accept applications for preliminary consultations and system impact studies from those who wish toconnect power generation facilities to the network and verify the results of studies conducted by general transmission and distribution companies. A collective study process for generator connection led by general transmission
and distribution companies was begun in October 2020 as a mechanism for systematically developing the networkwith a push-type approach that takes future power supply potential into account.

A non-ﬁrm access connection is an initiative to enable new power sources to come online and be operated within thescope of available capacity without having to increase facilities on the assumption that output curtailment will be
implemented if operational capacity is expected to be exceeded during normal times. In January 2021, it became
possible to apply a non-ﬁrm access connection to a backbone grid network in any area lacking available capacity. We
will also look into applying non-ﬁrm access connections to local grid networks.

Supply-demand condition
Network operation

Hybrid of ﬁrst-come, ﬁrst served basis and implicit auction

Non-ﬁrm access

Organization framework, etc.

All system users have to submit annual, monthly, weekly and day-ahead plans for generation and supply-demand via the
Cross-regional Operation System to OCCTO. OCCTO accepts these plans, conﬁrms the integrity of them, and grasps the
supply-demand balance condition on the basis of nationwide, supply area, and Electricity Company.

Roles of OCCTO

Supply-demand condition / Network operation

Grasp situation of nationwide supply-demand balance by planmanagement through the Cross-regional Operation System

Stable electricity supply

Supply-demand balance

Rule for Retail Companies and Generation Contractors tomake their plans and actual demands/generation
balance for the 30-min unit.
Electricity network
usage environment

Monitor Nationwide Conditionsof Supply-Demand andNetwork System Operation

A large amount of electricity cannot be stored; thus,
supply and demand need to be equalized constantly forstable supply. In the worst case, frequency ﬂuctuation due toimbalance of supply and demand may cause a large-scale
blackout.

Planned balancing rule

Monitor nationwide conditions of supply-demandand network system operation 24 hours a day, 365 days a year
Instructions for improvement of
supply instability situation to electricity companies■ Instructions by OCCTO
Main content to be monitored● Supply-demand conditions in each supply area and the main generator output condition● Cross-regional network conditions including the usage status of interconnection lines between supply areas● OCCTO has strong authority under the Electricity
Business Act to demonstrate effective control ability.
● All electricity companies are subject to instructions.
● OCCTOʼs instructions are applied not only in supply
shor tages, but al so in insuf ﬁcient suppression of
output capacity due to excess supply.

Training has been provided regularly in cooperation with members for supply shortages or power generation
problems at the Cross-regional Operation Center. Training with speciﬁc conditions strengthens the response capability
to secure a stable electricity supply.

Organization framework, etc.

■ Training for supply shortage

Supply-demand condition
Network operation

OCCTO monitors and grasps, on a real-time basis, information such as supply-demand conditions monitored at thecentral load dispatching centers in each supply area by introducing the Cross-regional Operation System.
Furthermore, OCCTO manages the plans and actual performance of system usersʼ supply-demand with monitoring
supply-demand balance in each supply area provides immediate and precise judgments and instructions such as how
much electricity supply, from/to electricity companies, etc.

In anticipation of large-scale natural disasters, which are becoming increasingly severe in recent years, we seek to work
closely with the Government and will fortify links and ties of coordination with disaster-prevention operations at anational level within the context of an emergency communications system and disaster-response arrangements established in accordance with the Disaster-Prevention Operational Plan. During normal times, we will continue to conductdisaster-response drills and improve the effectiveness of our business-continuity plan (BCP).
Furthermore, as an operation added by Act for Establishing Energy Supply Resilience, OCCTO will check the details of
disaster cooperation plan prepared by general transmission and distribution company beginning in July 2020 and ﬁeld
applications and grant subsidies under a mutual assistance system to cover and recover the costs of disaster recovery ona nationwide scale beginning in April 2021.

Based on the Electricity Business Act,OCCTO Performs the Fair and
Neutral Operation Management as an authorized organization

Roles of OCCTO

Organization framework, etc.

We are prepared to deal with large-scale disasters.

Stable electricity supply

General Affairs Dept.

Dispute resolution between electricity companies

OCCTO operates and maintains “Switching Support System.”
OCCTO contributes to information inquiries of consumersʼ facilities and usage amounts, and to acceleration and facilitation of
the switching of transmission network use agreements between Retail Companies and General Transmission andDistribution Companies.

Public and International Relations Ofﬁce

Reinforcing functions for collecting and transmitting information

General Planning Dept.

Study of ideal reserve and balancing capacity , studying, undertaking a detailed design of,and operating the capacity market

Network Planning Dept.

Demand forecast, aggregation of electricity supply plans, and formulation of long‒term development plan of cross-regional network and cross-regional network
development plan

Network Access Ofﬁce
Network Operation Dept.

Acceptance of preliminary consultation and system impact study
for power generation facility with over 10MW
Respond to power shortage, management of cross-regional interconnection lines,
coordination of maintenance work plans, and operation of Cross-regional Operation System

Cross-regional Operation Center

Audit Ofﬁce

Monitoring and management of supply-demand and power system condition

Respond to complaints and consultations, conciliation/arbitration(Main operations are listed.)

Supply-demand condition
Network operation

Dispute Resolution Ofﬁce

Electricity network
usage environment

OCCTO accepts consultations and complaints about transmission and distribution businesses from Electricity
Suppliers and provides mediation/conciliation between Electricity Suppliers. OCCTO acquired a certiﬁcation from the
Minister of Justice as the certiﬁed dispute resolution business operator in accordance with the “Act on Promotion of
Use of Alternative Dispute Resolution.”

Member liaison, formulation and review of rules for network use, operating
Switching Support System, disaster prevention, information security measures

Organization framework, etc.