Germany's aFRR Gold Rush Is Closing

Germany’s transmission operators purchase around 4.5 GW of battery-related balancing capacity, with about 90% going to aFRR. According to Modo Energy, the battery fleet will reach 5.7 GW by year-end. When you compare these numbers, it’s clear there’s more battery capacity coming online than the frequency market can support.

aFRR, or automatic Frequency Restoration Reserve, is the fast-acting reserve that grid operators use to fix short-term imbalances. So far, it’s been the most profitable area for German batteries. The market is reaching its limit sooner than many expect. About 580 MW have pre-qualified for aFRR, which is roughly 30% of all operational batteries. If just 35% of the 2026 battery fleet qualifies, that would already meet the 2 GW German TSOs need. Any new capacity after that will be competing in a market that’s already full. By August 2026, the timeline is down to months, not years.

We already know what happens when the market gets saturated, and Modo Energy’s analysts point straight to Great Britain as an example. In 2022, British batteries made over £150k per MW each year from frequency services. By 2023, that dropped to about £50k per MW, a 73% decrease, once supply outpaced demand. The hardest hit were short-duration systems designed only for frequency response. When that revenue stream dried up, they had no other way to earn.

Germany’s market rules aren’t exactly the same, but oversupply works the same way everywhere: more low-cost providers mean lower prices. At the current pace, Germany is about a year to a year and a half behind where Britain’s frequency revenues collapsed. Deployment is picking up speed, too. In just the first half of 2026, 888 MW came online, more than in all of 2025. And there’s even more capacity waiting to be added.

The revenue mix

You can see the shift in this year's numbers. In July 2026, aFRR-up capacity prices fell 35% in a single month to about €10/MW/h, and German BESS revenues dropped to €205k/MW/year. Part of that July move is seasonal, since strong summer solar leaves less scarcity to price. The direction still holds. Ancillary services still made up 55% of German battery revenue in 2026, split between aFRR and FCR (frequency containment reserve, the very fast first-response reserve). Modo expects that to invert. Near-term two-hour revenues of €240k/MW look set to roughly halve by 2030, with wholesale arbitrage supplying about 95% of what remains.

The money moves from being paid to stand by towards being paid to trade energy across the day-ahead and intraday markets, buying cheap and selling dear as solar swings prices around. A battery that can only sell availability watches its main revenue line thin. One that trades energy keeps earning as the mix rotates.

The Dutch market shows the same pattern from a different angle. There, aFRR capacity that paid €105/MW/h in 2022 pays €27/MW/h in 2026, down every year since, while the energy side of the market holds up. Capacity saturates first. Energy is where batteries keep earning. This isn't a German quirk. Reserve markets in Britain and France are already crowding after a record year for European storage build, on energy-storage.news reporting.

Build a battery for the next phase

Three things separate the assets that ride this out from the ones that won't. Duration, because two hours and above lets you shift real energy into wholesale windows rather than just hold power in reserve. Co-optimisation, because the value now sits in switching between aFRR energy, mFRR (the manually activated reserve), day-ahead and intraday hour by hour, not in parking capacity in one auction. And warranty discipline, because chasing wholesale spreads with aggressive cycling only pays if it respects the limits your cells are guaranteed for.

This is harder for smaller assets, and it's exactly where aggregation earns its place. A single 1 to 5 MW battery rarely has the scale or the trading desk to co-optimise across every market in real time. Pooled into a virtual power plant, a fleet of distributed batteries dispatched as one, those same assets clear market thresholds and spread revenue across services rather than betting the business case on a single saturating auction.

That's the job Hive Power's FLEXO does. It co-optimises each battery across ancillary and wholesale markets, and holds cycling inside warranty limits, so a portfolio built today isn't priced for a revenue stack that's already fading.

By the end of 2027, wholesale and intraday trading will make up the majority of German BESS revenue, and the aFRR-first business case that financed the 2024 to 2025 boom will read as a historical artefact. The winners will be the batteries built, optimised and funded for the wholesale era now. That work happens before frequency revenue thins to match Britain's. The gold rush isn't over.

FAQ

Why are German battery ancillary revenues falling in 2026? Supply is catching up with demand. German TSOs procure about 4.5 GW of battery-relevant balancing capacity, while the fleet is on track for 5.7 GW before the year is out. As more batteries pre-qualify, competition drives clearing prices down. In July 2026, aFRR-up capacity prices fell 35% in a single month, on Modo Energy figures.

Where will BESS revenue come from as ancillary markets saturate? Wholesale trading, mainly day-ahead and intraday arbitrage. Modo Energy expects wholesale to supply about 95% of German two-hour BESS revenue by 2030, up from a minority share today. Longer-duration batteries that can shift energy across the day, rather than only hold reserve capacity, are best placed to capture it.

What does market saturation mean for a 1 to 5 MW battery project? Smaller assets feel the squeeze first, because they often rely on a single revenue stream and lack the scale to trade across markets. Aggregating them into a virtual power plant (VPP) lets them meet market entry thresholds and co-optimise across ancillary and wholesale markets, spreading revenue rather than depending on one saturating auction.

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