The European Power Exchange (EPEX SPOT) has announced that it will vote against the planned introduction of 15-minute time intervals (Market Time Units, MTU) in Single Day-Ahead Coupling (SDAC) from 11 June 2025. This decision is based on significant operational concerns that arose during the recent test phases. EPEX SPOT therefore requests a postponement of the go-live date to 1 October 2025 to ensure system stability and market reliability.

Background: Integration of 15-minute products

The introduction of 15-minute products in the SDAC aims to improve the integration of renewable energies and increase grid stability. While 15-minute products have already been largely implemented in Single Intraday Coupling (SIDC), the implementation in SDAC poses a significant challenge.

Operational concerns of EPEX SPOT

EPEX SPOT identified several critical issues:

• High failure rates during tests: In the tests in February and March 2025, approximately 20% of the sessions ended with a complete market decoupling - an unprecedented event in the market coupling process.

• Overloading of the matching algorithm: The introduction of 15-minute products significantly increases complexity, which puts pressure on the central matching algorithm.

• Insufficient quality assurance: Several test phases were completed without fulfilling the agreed quality criteria.

Jean-François Conil-Lacoste, CEO of EPEX SPOT, emphasised: "Market participants need clarity. This ongoing uncertainty about a change that is coming so soon with profound consequences must end."

Proposal for a new timetable

EPEX SPOT proposes to postpone the go-live date to 1 October 2025. This would provide additional time to revise operating procedures, system tests and ensure market stability. Eurelectric had already proposed this date as its preferred go-live date in December 2024.

EPEX SPOT's decision emphasises the importance of operational security and market reliability when introducing new market mechanisms. A well-considered postponement of the go-live date could help to ensure the long-term stability and efficiency of the European electricity market.