National Grid said it “operates one of the most reliable electricity systems in the world, and frequency deviations outside our required limits are extremely rare”.
Matching power supply and demand can be more challenging when there are more intermittent sources of power on the system, such as wind and solar plants. These green sources of energy also lack the ability of fossil fuel generators such as coal and gas-fired plants to help stabilise the grid even if the generator has tripped, by providing inertia.
Renewable power generated more electricity than fossil fuels in the UK in 2020 for the first time. During the year, 43.1pc of UK power came from renewables and 37.7pc from fossil fuels, with nuclear and imports making up the bulk of the rest. Britain now goes for long stretches without using domestic coal-fired power stations, and officials want to be able to run the grid without gas-fired generation for short periods by 2025.
National Grid ESO, which balances Britain’s electricity supply and demand, has introduced new techniques to help it manage frequency even as the power system evolves, including technology to respond more quickly to frequency changes, and making generators less sensitive to falls in frequency.
Tom Edwards, at Cornwall Insight, said giant power cables connecting the British power grid to the Continent are a growing cause of frequency changes.