Frequency Control and Ancillary Services: New Revenue for Batteries
Because a battery responds in milliseconds, it is ideal for frequency control and ancillary services — a strong additional income stream for independent storage.
What are ancillary services?
Ancillary services are those needed to keep the grid's frequency and balance stable. In Türkiye they are procured by the system operator TEİAŞ under the Electricity Market Ancillary Services Regulation.
Primary and secondary frequency control
- Primary frequency control: mandatory for licensed plants above 30 MW; responds automatically at ±200 mHz frequency deviation.
- Secondary frequency control: optional; selected units receive an automatic signal from TEİAŞ and adjust active output within a set range (MAXC–MINC).
The battery's edge: speed
Because BESS can ramp to full power and back within milliseconds, it has a clear advantage over thermal and hydro units in frequency control. The regulation lets not only licensed generators but also independent electricity storage facilities provide these services as certified ancillary service units.
TEİAŞ procurement
TEİAŞ announces the tender specification for capacity procurement at least once a year, at least 90 days before the procurement date. The market clearing price (PTF) published by EPİAŞ is used as a reference price.
Combined with revenue stacking
Ancillary income is not evaluated alone; together with arbitrage, peak shaving and self-consumption it layers the battery's return. In a storage-backed solar setup, ancillary services are an important additional income channel.
Assess your battery's ancillary-services income potential with Egesa.Frequently Asked Questions
What is an ancillary service?
Services that keep the grid's frequency and balance stable; in Türkiye procured by TEİAŞ under the Ancillary Services Regulation.
Why is a battery ideal for ancillary services?
BESS ramps to full power and back in milliseconds, responding far faster than thermal/hydro units in frequency control.
Can an independent storage facility provide ancillary services?
Yes. The regulation allows independent electricity storage facilities to provide them as certified ancillary service units.
What is the difference between primary and secondary?
Primary control is mandatory and automatic (±200 mHz); secondary is optional and adjusts output within a set range via an automatic TEİAŞ signal.