On 10 June 2026, transmission system operators (TSOs) submitted a proposal to ACER to revise the harmonised allocation rules (HAR) and the requirements for the single allocation platform (SAP).
To inform its decision-making process, ACER will open a public consultation on 10 July 2026.
What are these rules about?
The harmonised allocation rules apply to all allocations of long-term transmission rights performed in the European Union. They provide specifications for the auctioning of long-term transmission rights (including their use, curtailment and eligibility criteria) and go through a review process every two years. All TSOs issuing long-term transmission rights are required to offer-long term cross-zonal capacity to market participants through the single allocation platform.
Why amend them?
With the implementation of long-term flow-based allocation, long-term transmission rights for all bidding zone borders within a capacity calculation region will be allocated with a single auction.
Currently, collaterals (i.e. financial security provided by market participants to guarantee their payment obligations) for long-term transmission rights are reserved until the auction is cleared, often leading to an overestimation of collaterals’ needs. As long-term flow-based allocation combines multiple bidding zone borders, this over-reservation further increases collateral requirements for market participants. This, in turn, may result in unnecessary bid rejections by market participants and potential welfare losses.
To address this, TSOs propose to amend the harmonised allocation rules and the single allocation platform requirements by introducing a new collateral management solution.
What are the next steps?
The public consultation will run from 10 July until 7 August 2026.
ACER will analyse the feedback received and reach a decision by 10 December 2026.
