ACER amends the harmonised allocation rules for long-term electricity transmission rights
What is it about?
On 27 March 2025, ACER received the transmission system operators’ (TSOs’) proposal to amend the harmonised allocation rules (HAR) for long-term electricity transmission rights.
The harmonised allocation rules apply to all long-term transmission rights allocations conducted within the European Union, specifying criteria for their auctioning (including use and curtailment of long-term transmission rights, eligibility criteria, etc.).
The TSOs’ proposal included various updates related to arrangements with market participants, reflecting upcoming market changes (e.g. introduction of 15-minute market time unit in the day-ahead electricity market) and recent incidents (e.g. single day-ahead market decoupling in June 2024).
To take an informed decision, ACER consulted stakeholders during Spring 2025.
What did ACER decide?
ACER approves the TSOs' proposal, while adding some clarifications and proposing further reviews on the:
- Usage of the day-ahead price for remunerating long-term transmission rights in case of decoupling: ACER recommends TSOs and national regulatory authorities to review the arrangements among nominated electricity market operators (NEMOs), which should set transparent rules for defining the single day-ahead reference price in case of decoupling.
- Relevant rules for the nomination of physical transmission rights: ACER recommends TSOs and national regulatory authorities to review the applicable nomination rules, considering the introduction of 15-minute market time unit in the day-ahead market.
ACER agreed with TSOs to tackle improvements to the collateral requirements in long-term flow-based auctions separately.
What are the next steps?
TSOs and regulatory authorities should now review nomination rules and multiple NEMOs' arrangements to reflect the latest updates introduced by ACER.