# Primary control reserve (PRL)

Also known as: Primärregelleistung, PRL, Primärregelung, FCR, Frequency Containment Reserve, Primary control

Primärregelleistung (primary control reserve, PRL) is the first tier of control reserve in the Swiss electricity grid: it stabilises grid frequency automatically within 30 seconds of a disturbance, such as the outage of a power plant. Swissgrid held around 70 MW for this on annual average in 2025; from 2026 it is 80 MW (ElCom). The minimum bid is 1 MW; smaller systems take part through a pool. Battery storage systems suit this product because they change their output in both directions without start-up time.

Canonical page: https://www.ampere-dynamic.ch/en/knowledge/glossary/primaerregelleistung/

Primary control reserve responds directly to grid frequency: if it drops below 50 Hz, the participating systems feed in more; if it rises, they cut back. The response is local, with no signal from Swissgrid, and the reserve is held symmetrically in both directions. After 30 seconds, [secondary control reserve](https://www.ampere-dynamic.ch/en/knowledge/glossary/sekundaerregelleistung/) takes over (Swissgrid Balancing Roadmap).

For businesses, PRL is rarely the first step into the balancing energy market: the volume of around 70 MW is small, and holding the reserve requires a battery that stays permanently available in both directions. More often, storage systems combine secondary control reserve with peak shaving and self-consumption.

Which of the three tiers is an option for your system and what the market pays for it is explained in the article [Balancing energy with battery storage](https://www.ampere-dynamic.ch/en/knowledge/balancing-energy-battery-storage/). Market access runs through a [pool](https://www.ampere-dynamic.ch/en/knowledge/glossary/pooling/).

## Related terms

- [Balancing energy](https://www.ampere-dynamic.ch/en/knowledge/glossary/regelenergie/)
- [Secondary control reserve (SRL)](https://www.ampere-dynamic.ch/en/knowledge/glossary/sekundaerregelleistung/)
- [Tertiary control reserve (TRL)](https://www.ampere-dynamic.ch/en/knowledge/glossary/tertiaerregelleistung/)
- [Pooling](https://www.ampere-dynamic.ch/en/knowledge/glossary/pooling/)