In August 2025, ACER has received a proposal from Nominated Electricity Market Operators (NEMOs) to amend the harmonised maximum and minimum clearing price (HMMCP) methodologies for the EU day-ahead and intraday market coupling.

On 4 February 2026, ACER has approved the proposal, and NEMOs are now required to promptly implement the amendments.

Why does this matter?

Market coupling (of day-ahead and intraday markets) allocates scarce cross-zonal transmission grid capacity efficiently by coupling wholesale electricity markets across the EU, while taking into account physical grid constraints.

The HMMCP methodologies set the maximum and minimum price limits in the EU single day-ahead and intraday electricity markets. They also define the harmonised automatic price adjustment mechanism and specify how it is triggered when the applicable price limits are reached in the day-ahead and intraday markets.

What’s new in the methodologies?

The amended methodologies now clarify how the automatic price adjustment mechanism applies in rare market conditions. In case of partial decoupling within a bidding zone where multiple NEMOs operate but not all are decoupled, the harmonised automatic price adjustment mechanism cannot be triggered.

Read more.

See the ACER Decision 02/2026 (day-ahead) and the ACER Decision 03/2026 (intraday).