European Union – November 06, 2026 -- The EU Agency for the Cooperation of Energy Regulators (ACER) has published a preliminary version of EU-Flex, an open-source electricity market model built to assess flexibility needs across the bloc, ahead of its first formal assessment in July 2027.
ACER must estimate EU flexibility gaps under the 2024 market reform
The 2024 Electricity Market Design reform tasks ACER with estimating flexibility needs across the EU and identifying gaps between those needs and available flexibility. The agency must also recommend actions on cross-border issues. Flexibility is defined as the power system's ability to respond to changes in supply and demand. Growing renewable generation and electrification across sectors raise the requirement for it, in order to secure supply, integrate new renewables and keep electricity affordable.
EU-Flex simulates the European electricity market and cross-border cooperation
EU-Flex simulates the European electricity market to show the flexibility challenges facing the EU power system and how cross-border cooperation can address them. ACER is releasing it early to make its analysis more transparent and let stakeholders test the approach and contribute to the model's development.
The release comprises three items:
- a short paper introducing the model, with a test case;
- a preliminary model, including source code and test case input data;
- a document describing the methodology.
Stakeholders have until 17 December 2026 to submit feedback
Feedback on the paper and methodology goes through ACER's public consultation. Comments on the preliminary model go through ACER's GitHub repository. Both channels close on 17 December 2026.
ACER will present the model in a free webinar on 17 November 2026. The session will cover its key features and demonstrate how to run it.