​Automatic frequency restoration reserve (aFRR) is Germany’s largest ancillary service by capacity and TSO spend.

Battery qualification has been increasing 50% year-on-year, but value depends on two coupled markets: aFRR capacity and aFRR energy.

Subscribers to Modo Energy’s German research will discover:

• The size of the market
• How aFRR capacity and aFRR energy markets work (products, gate times, pricing structure)
• Pre-qualification requirements
• Key strategic implications for BESS

1. What is aFRR & why it suits batteries

Frequency services are critical for maintaining European grids stable at 50 Hz.

Europe has three main frequency services:

FCR: Frequency Containment Reserve

aFRR: Automatic Frequency Restoration Reserve

mFRR: Manual Frequency Restoration Reserve (not typically used by batteries)

The graph below illustrates how they work together to keep grid frequency in check.

​

aFRR follows FCR and precedes mFRR. Providers must begin responding within 30 s and reach full activation within 5 min.

Why aFRR suits batteries

• Batteries have fast ramp times that match aFRR's activation signals.