ACER approves changes to the PICASSO and MARI balancing frameworks

Serguey Asael Shinder22 September 2026, 17:372 min read

Two European balancing platforms are getting revised rulebooks. ACER signed off on changes to how PICASSO and MARI operate, publishing Decisions 12/2026 and 13/2026 on 22 September 2026 and accepting what every electricity transmission system operator had jointly put to it on 18 December 2025. Both platforms trade the energy used to restore system frequency.

The frameworks exist under the Electricity Balancing Regulation and harmonise how balancing service providers take part in balancing markets across member states. PICASSO coordinates cross-border exchange of automatically activated balancing energy; MARI does the same for manually activated energy. Together they let TSOs reach balancing resources across borders to manage unexpected gaps between supply and demand.

The TSOs proposed two things. The first is further harmonisation of BSP prequalification — the process that establishes whether a generation or demand unit meets the technical and operational requirements to provide balancing services. The second is a common process for amending the implementation frameworks of both platforms, aimed at further harmonising terms and conditions for providers.

What it means

Prequalification is where market access is actually decided, and it has been the quiet reason a unit that can technically balance in one member state cannot sell that service in another. Harmonising it does more for cross-border liquidity than any change to the platforms themselves, because it reduces the number of national processes an operator must satisfy to reach the same pool.

The second proposal is the one to watch over a longer horizon. A common amendment process is governance plumbing with no immediate effect on anybody's business case, and it determines how quickly these frameworks can be changed again. Frameworks that are hard to amend ossify around the technology that existed when they were written — which, for platforms meant to accommodate batteries and demand response alongside conventional plant, is the failure mode worth designing against.