Milestone for the European electricity market: New calculation method improves short-term electricity trading and the integration of renewables

Since 14 October 2026, the new Core Intraday Capacity Calculation process IDCC(e) has been in operation. Its aim is to use the existing grid infrastructure as efficiently and optimally as possible for cross-border trading while maintaining operational security. This enables electricity from highly fluctuating renewable generation to be integrated into the system even more effectively.

Austria’s transmission system operator Austrian Power Grid (APG) has played a leading role in developing and implementing the method, which is used several times a day to calculate the capacities available for cross-border intraday electricity trading. “What is crucial for a functioning intraday market – alongside maintaining operational security – is knowing which grid capacities are actually available at any given time in order to make them available to market participants in an optimised and secure manner,” says Harald Köhler, Head of System Management at APG. He explains: “Our objective is to calculate cross-border capacities using the most up-to-date information possible, allowing us to respond flexibly to short-term changes in the electricity system. This is especially important when actual generation or consumption diverges from forecasts – for instance, as a result of changing weather conditions – or when transmission lines or power plants are affected by outages. The intraday market thus plays an increasingly important role in the integration of renewable energy and is an essential building block of an energy transition that safeguards security of supply.”

Close European cooperation safeguards system operation and security of supply

As of today, 18 European transmission system operators have successfully implemented the fifth and final coordinated Intraday Capacity Calculation (IDCC) process for short-term electricity trading in Europe’s Core Capacity Calculation Region. 50Hertz Transmission, Amprion, Creos Luxembourg, ČEPS, ELES, EirGrid, Elia, HOPS, MAVIR, PSE, RTE, SEPS, SONI, TenneT TSO, TenneT TSO B.V., Transelectrica, TransnetBW and APG now jointly calculate the cross-border grid capacities that can be made available and used as efficiently as possible for European electricity trading. The calculations incorporate the latest grid, market and forecast data.

“The now successfully completed implementation of IDCC demonstrates how important close cooperation among European transmission system operators is for a functioning and integrated electricity market. As APG, we are thus making a concrete contribution to security of supply and to the further integration of European electricity markets,” Köhler emphasizes.

The latest development in detail: Data updated until 4:00 p.m.

The IDCC(e) process reassesses cross-border intraday capacities for market time units between 6:00 p.m. and midnight. The results are available at around 4:00 p.m. on the day of delivery. For Austria, the process covers the bidding zone borders with Germany, Czechia, Hungary and Slovenia.