Europe reshapes capacity calculation regions to improve cross-border power flows

In July 2025, electricity transmission system operators (TSOs) submitted to ACER their proposal to amend how capacity calculation regions (CCRs) are defined across Europe.

With its Decision 10-2025, ACER has approved the proposed amendments.

What are capacity calculation regions and why are they important? 

CCRs are geographic areas across Europe that group neighbouring electricity bidding zones and their borders. Within each region, TSOs work together to determine how much electricity can safely flow across borders while ensuring security of supply.

There are currently nine CCRs in the EU: Nordic, Hansa, Core, Italy North, Central Europe (CE), Greece-Italy (GRIT), South-West Europe (SWE), Baltic and South-East Europe (SEE).

Well-defined CCRs benefit European consumers and producers by: 

• helping TSOs coordinate regional processes such as capacity calculation, redispatch and countertrading more effectively; and
• optimising cross-zonal capacity, facilitating electricity trade across borders and ensuring security of supply.

What did ACER decide?

ACER assessed whether the TSOs’ proposal supports market integration, non-discrimination, effective competition and the well-functioning of the EU electricity market.

Following a public consultation in summer 2025, ACER has approved the TSOs’ proposal to:

• Merge two existing CCRs (Core and Italy North) into the Central Europe CCR across multiple timeframes and methodologies. The Central Europe CCR, previously limited to the day-ahead timeframe, will now also cover:
  • intraday capacity calculation;
  • regional operational security coordination (ROSC); and
  • coordinated redispatching and countertrading (RDCT), along with their cost-sharing methodology (RDCT CS).

• Expand the existing South-East Europe CCR and establish three new CCRs (East-Central Europe*, Italy-Montenegro and Eastern Europe) to include the bidding zone borders and TSOs of the Energy Community Contracting Parties and neighbouring EU countries.

  *The ECE region is established as a temporary setup, with the intention to merge it with the Central Europe CCR in the future.

  These changes are necessary to reflect the growing integration of Energy Community countries into the EU electricity market and strengthen cooperation and efficiency across borders.

Next steps

Once the conditions for integrating the East-Central Europe CCR into the Central Europe CCR are met, TSOs shall submit to ACER a new proposal to formally merge the two regions.