ACER has adopted a Decision amending the electricity redispatching and countertrading cost sharing methodology for the Core capacity calculation region, concluding the review process initiated in October 2025.
What is the methodology about?
The cost sharing methodology allocates the costs of redispatching and countertrading remedial actions within a capacity calculation region. These actions are triggered to address network congestions occurring within the region.
Specifically, this methodology tracks how each remedial action affects congested network elements and assigns the related costs to the responsible transmission system operators (TSOs), based on the order of flow types (loop, internal, allocated and power-shifting transformer flows). Loop flows are charged first, however, the portion below a given threshold is to be exempted.
What did ACER decide?
After reviewing the methodology and consulting Core TSOs and regulatory authorities, ACER introduced the following changes:
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requiring Core TSOs to analyse and provide the loop flow threshold;
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confirming the Power Flow Colouring (PFC) method for decomposing physical flows, providing a detailed explanation in the decision.
Next steps
The Core TSOs must implement the amended long-term capacity calculation methodology as soon as possible, along with the Core Regional Operational Security Coordination (ROSC) methodology.
