Prolonged periods of low wind and solar power could trigger blackouts as Britain races to ditch fossil fuels, experts have warned.
The country can expect to suffer a slump in wind known as a dunkelflaute – or “dark wind lull” – every 20 years and the system needs to be able to cope, academics from Imperial College London have warned.
Wind farm output fell to 0.6GW on March 3 amid the longest spell of low wind in more than a decade, they said.
The academics urge greater investment in technologies that can help bridge gaps in power supply when the wind is not blowing and the sun is not shining. Their report was commissioned by the hydro-power and biomass power station owner Drax.
Dr Iain Staffell, of Imperial College London, said: “It’s time for Britain to get serious about the threat of extreme weather events to our electricity system.
“Renewable power sources have made our country cleaner and greener, but as they rely on the ever-changing British weather, completing our transition away from fossil fuels comes with serious challenges.”
The UK’s power system has gone through a major overhaul in the last two decades. Wind and solar power accounted for 23.8pc of electricity generated in 2019, compared to a negligible amount in 2000.
Ministers now want renewable power to take on an even bigger role as they try to slash carbon emissions. Boris Johnson is seeking to quadruple offshore wind capacity. The UK is legally committed to reducing fossil fuel use by 78pc by 2035, and to achieving net zero carbon emissions by 2050.
Gas-fired power stations currently tend to pick up the slack at times of low wind and solar output. In 2019, gas accounted for 40.6pc of UK electricity generation. However, reliance on gas-fired power stations will need to reduce if the UK is to cut carbon emissions.
Drax highlighted the benefits of its hydro-power stations as a stand-by source of power instead of gas. Its Cruachan facility pumped hydro-power storage site in Scotland has a six-year contract to help stabilise power demand and supply. Drax is planning to expand the site.
Will Gardiner, chief executive, said: “A new generation of pumped hydro storage power stations will allow the UK to decarbonise faster and cheaper.
“These water batteries soak up surplus power from wind and solar farms and then release it to plug gaps during extreme weather events.”