ACER amends cost sharing rules for electricity redispatching and countertrading in the Core region

In brief

ACER has amended the methodology used to share the costs of electricity redispatching and countertrading in the Core capacity calculation region, completing a review launched in October 2025. These remedial actions are used to relieve grid congestion, and the methodology determines how their costs are allocated among transmission system operators according to the effects of different power-flow types. The Core region is the EU’s largest capacity calculation region, covering 19 bidding-zone borders and 16 transmission system operators across 13 Member States.

Following consultations with transmission system operators and national regulators, ACER required the operators to analyse and justify the threshold below which loop flows are exempt from charges. It also confirmed the Power Flow Colouring method for separating physical electricity flows and provided a more detailed explanation of its application. Core transmission system operators must implement the amended rules as soon as possible alongside the region’s long-term capacity calculation and operational security coordination methodologies.

Source: ACER

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