Today, ACER publishes its 2025 Monitoring Report on electricity cross-zonal capacities and congestion management.
ACER Director, Christian Zinglersen, is in Copenhagen today to present key insights from the ACER report at the Council’s informal meeting of energy ministers under the Danish presidency.
The 2019 Clean Energy Package introduced a legal requirement on EU electricity transmission system operators (TSOs) to make at least 70% of their physical transmission capacity available for cross-zonal trade (by the end of 2025 at the latest) on all lines of cross-zonal relevance. This ensures that enough transmission capacity is allocated for cross-zonal trade with neighbours and mitigates discrimination against cross-zonal trade in favour of internal trade.
This ACER report highlights the importance of implementing the ‘70% rule’ to facilitate more cross-zonal electricity trade. Increasing the level of electricity trade between EU Member States enhances the resilience of the power system, optimises available resources and facilitates the efficient integration of renewable energy.
What are ACER’s findings?
- Untapped value of additional cross-zonal trade: Persistent price differences between bidding zones highlight the need for more cross-zonal trade to unlock further market benefits.
- Meeting the 70% requirement would:
- Ensure that domestic electricity flows are not prioritised over cross-border trade.
- Reduce price volatility and price spikes (such as those seen in summer 2024 across South-East Europe).
- Bring additional welfare to EU electricity markets. In 2024 alone, meeting 70% in the Core region would have provided at least EUR 580 million in economic welfare through more electricity trading, had Core region TSOs implemented the 70% rule.
- Progress, but work to be done as the ‘end-2025 deadline’ is at risk: While TSOs are progressing (Core region TSOs made available on average 54% of the capacity on the most congested lines in 2024), implementation delays could prevent some of them from meeting the legal deadline (of 70% on all relevant lines) at the end of 2025.
- Growing grid congestion: Delays in grid reinforcement continue to widen the gap between grid development and system needs, ensuring continued reliance on costly remedial actions to relieve grid congestion. In 2024, EU TSOs spent €4.3 billion on 60 TWh (comparable to Austria’s annual electricity consumption) of remedial actions to manage EU power grid congestion.
What are ACER’s recommendations?
This ACER report underlines the importance of cross-zonal trade as a key source of power system flexibility, helping to shield consumers from price volatility and support the growth of renewables. ACER recommends:
- Member States and TSOs to prioritise the 70% requirement using the different options available e.g. investing in grid-enhancing technologies (non-wire alternatives) to increase network capacity.
- TSOs and nominated electricity market operators (NEMOs) to continue improving how available cross-zonal capacity is calculated and allocated.
- TSOs to promptly implement the EU framework for congestion management to ensure grid congestion is addressed efficiently and in a coordinated manner.
Explore ACER’s interactive dashboard for data on cross-zonal electricity trade, congestion management costs and progress in meeting the 70% capacity rule by region.
