ACER amends price limit methodologies for EU short-term electricity markets
What is it about?
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 NEMOs’ proposal.
Why is market coupling important?
Before market coupling was introduced in the EU, electricity and cross-zonal transmission grid capacity had to be purchased separately. Today, 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.
What are the methodologies about?
The HMMCP methodologies (first approved by ACER in 2017 and amended in 2023) set the maximum and minimum price limits in the EU single day-ahead and intraday electricity markets.
Established under the Capacity Allocation and Congestion Management (CACM) Regulation, the methodologies 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.
Why amend the methodologies and what’s new?
ACER amended the methodologies to 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 bidding zone will remain in market coupling, potentially with low liquidity. The amended methodologies clarify that, in such cases, the harmonised automatic price adjustment mechanism cannot be triggered.
What are the next steps?
Following this ACER Decision, NEMOs are required to promptly implement the amendments.