Energy Storage Systems (BESS) – Frequency Response

What do Energy Storage Systems have to do with Frequency?

The National Grid can use Energy Storage Systems to increase the frequency. For instance, when events such as power stations going offline occur. Battery energy storage systems can respond very quickly to requests from the Grid, which is critical as this needs to occur in less than 2 seconds. The other Frequency Response systems in place are not as quick as they involve power generators increasing their output, which although relatively quick (i.e. minutes) is not quick enough.

What is system frequency?

If power demand is greater than generation, the frequency falls, however if generation is greater than demand, the frequency rises. System frequency is a constantly changing variable, consisting of the real time balance between system demand and total generation.

Within the UK, the National Grid has a licence obligation to keep frequency within the limits specified in the ‘Electricity Supply Regulations’, i.e. ±1% of nominal system frequency (50.00Hz). The National Grid must therefore ensure that sufficient generation and/or demand is held in automatic readiness. In other words to manage all credible circumstances that might result in the frequency exceeding the limits.

Energy Storage Systems (BESS) - Frequency Response

Monitoring of UK Frequency showing fluctuations




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