ACER Publishes Preliminary EU-Flex Electricity Model
The open-source model simulates the European electricity market ahead of the EU's first flexibility needs assessment in 2027.
Updated on Nov. 5, 2026 in Utilities
The EU Agency for the Cooperation of Energy Regulators (ACER) has published a preliminary version of EU-Flex, an open-source model that simulates the European electricity market. The release includes a short introductory paper with a test case, source code, test case input data, and a methodology document.
Why it matters
The EU's 2024 Electricity Market Design reform tasks ACER with estimating flexibility needs across the EU, a task that grows more pressing as renewable generation expands and electrification spreads across sectors. Sharing the model ahead of the 2027 assessment is intended to make the analysis more transparent.
ACER has set 17 December 2026 as the deadline for stakeholder comments on the paper, methodology and preliminary model, with a webinar presenting the model scheduled for 17 November 2026. The first formal EU flexibility needs assessment is planned for July 2027, and no model results have yet been published.
The players
ACER (EU Agency for the Cooperation of Energy Regulators)
The European Union agency that coordinates national energy regulators and oversees cross-border electricity and gas market rules across the bloc.
The details
Stakeholders can comment on the paper and methodology through ACER's public consultation, and on the preliminary model via the agency's GitHub repository. ACER developed EU-Flex as an open-source tool so that its approach to simulating the European market can be inspected and tested by outside parties.
Timeline
2024: EU Electricity Market Design reform assigns ACER the flexibility assessment task.
5 November 2026: ACER publishes the preliminary EU-Flex model.
17 November 2026: ACER holds a webinar presenting the model.
17 December 2026: Deadline for stakeholder input on the model.
July 2027: First EU flexibility needs assessment is planned.
Roadmap
The EU-Flex release is a concrete step in implementing the 2024 Electricity Market Design reform, which assigned ACER the task of estimating flexibility needs across the bloc. It follows a broader European push to make power systems more adaptable as renewable generation and electrification grow.
Energy market participants and stakeholders can influence how flexibility needs are modeled by commenting before the 17 December 2026 deadline. The model's eventual assessment could shape future EU market design choices affecting electricity pricing and grid investment.
The takeaway
Because EU-Flex is open source, anyone can test and critique how ACER simulates Europe's power market before the first official assessment arrives. Engaging with the consultation now is the most direct way to shape the results.
What happens next
Stakeholders have until 17 December 2026 to submit comments on the EU-Flex paper, methodology and preliminary model, and ACER's first EU flexibility needs assessment is planned for July 2027.
Further reading
For context on how grid planning and power market design shape the sector, explore our Utilities coverage.
Source note: This article includes information reported by Europa.
