​Modo Energy's July 2026 release is out. German BESS revenues rise slightly versus the April release, based on an update to ancillary price modelling. Ancillary markets now saturate more slowly, because a growing share of new batteries connect under Flexible Connection Agreements (FCAs) that restrict ancillary participation.

For an unconstrained 2-hour battery, cumulative revenues increase 5% over 25 years. The uplift is concentrated in 2027 to 2029, then ancillary prices converge to the same level as last release, at which point wholesale markets draw equal or more opportunity for BESS. And the dispatch model now supports ramp limits of up to 30 minutes, to reflect more recent FCAs.

Key takeaways

• The dispatch model now runs ramp limits up to 30 minutes or 3.3%/min. A 30-minute ramp costs a 4-hour battery around 9% of its 20-year revenue.
• German unconstrained 2-hour BESS revenues rise around 5% over 25 years versus April, driven by slower ancillary saturation.
• Only about half of new BESS capacity is now assumed to reach full FCR and aFRR participation, reflecting the spread of flexible connection agreements.
• The uplift is ancillary-driven. On a pure merchant strategy, July and April revenues are almost identical.

You can now model ramp limits of up to 30 minutes

Grid operators increasingly ask batteries to ramp slowly. Distribution operators in particular attach ramp-rate limits to connection offers, and more developers accept these terms to connect sooner. The dispatch model now reflects this. It supports ramps that take longer than 15 minutes to cross the full power range, equivalent to rates below roughly 6.6% per minute, up to a 30-minute limit.

Slower ramps cost revenue. A battery that cannot move quickly loses access to fast products first.

Even a mild 2.5-minute ramp cuts 20-year revenue by 2.8%. A 15-minute limit costs 6.3%, and a 30-minute limit reaches 8.9%. The reason sits in intraday volatility: a battery that has to ramp up and down during a 15-minute spike can sell less volume during that spike, or forego it altogether.

Ancillary prices saturate more slowly as connection terms bite

The previous forecast assumed every new battery reached full FCR and aFRR participation after a prequalification lag. That assumption no longer holds. Almost all new German batteries now connect under a flexible connection agreement (FCA), and many of these restrict ancillary access.

Over the last quarter, more clarity appeared around FCA terms - the caps aFRR participation at 30%. Many TSO-level assets see constraints around 50%. Based on these recent updates, Modo Energy now assumes that 50% of all newbuild BESS capacity participates fully, choosing a slightly conservative estimate.