Britain recently started burning coal to generate electricity after a heat wave made solar panels too hot to work efficiently. High temperatures reduced the amount of energy generated from its solar panels. Electricity supply was also lower because of depressed wind speeds, lowering turbine output, and because some natural gas plants were down for maintenance. To meet a net zero carbon emissions mandate by 2050, Britain has increased its renewable capacity, and is now receiving 31 percent of its electricity generation from wind and solar power, which are not dispatchable (available on demand) and not reliable sources of electricity.


Fast Facts

  • Recent heat waves reduced the efficiency of Britain’s solar panels and lowered its wind output, threatening its grid and calling into operation idled coal plants.
  • The National Grid is paying idled coal plants to ensure Britons can keep their lights on and industries operating.
  • The birthplace of the Industrial Revolution, which used coal to become a world economic and political powerhouse, is now reeling as it reduces reliance upon traditional energy sources and focuses on weather-based wind and solar power.


Britain has started burning coal to generate electricity for the first time in a month and a half after a heat wave lowered output from its solar panels. Solar panels are tested at a benchmark of 25 degrees Celsius. For every degree increase in temperature above that level, its efficiency is reduced by 0.5 percentage points. The temperature level refers to the solar cell temperature, not the air temperature. In direct sunlight, the cells can easily reach 60 or 70 degrees. Compared with a cool cloudy day, the cells could be up to 25 percent less efficient during a heat wave.

The power came from a unit at Uniper’s Ratcliffe-on-Soar coal power plant in Nottinghamshire and another coal-powered plant was warmed up in case it was also needed. The Ratcliffe-on-Soar power station was due to be shut last year and is now scheduled to be closed next year. Britain has a target to close its coal-fired power plants by October 2024 as part of efforts to cut fossil fuel carbon dioxide emissions and meet its 2050 net-zero target. Britain’s grid had been coal-free for 46 days, shy of the nearly 68-day record it set in the summer of 2020, which was the longest single period since 1882 that the grid went without burning coal to produce electricity. The COVID pandemic was at a peak at that time and lowered demand.

In Europe, there have been concerns over electricity shortages amid disruption to natural gas supplies triggered by Russia’s war on Ukraine and outages in the French nuclear fleet. France is normally a major exporter of power to Britain and the Continent, but outages on its nuclear fleet turned it into a net importer during the first half of 2022.

EDF, Uniper and Drax agreed to keep their coal units open for back-up supply if needed this winter under special winter contingency contracts with National Grid. Uniper is preparing to keep open one of its units next winter (2023/24) that was due to close in September 2022 under National Grid’s normal market for back-up power supply. It is one of four units at its station in Ratcliffe-on-Soar, Nottingham. The other three were always planned to remain open until September 2024.

Keeping coal as backup power comes with a cost. Last summer, the National Grid Electricity System Operator (ESO) negotiated a winter contingency contract with five coal generators. At the time of the contract, the cost was forecasted to be around £340 million ($406 million) to £395 million ($471 million) and was subject to the procurement of coal. If and when the units were called upon to run, the cost of the European carbon allowance would be added.  Coal became an insurance policy against the failure of intermittent renewable energy to generate electricity.

So, what happens once the coal plants shut down and the weather causes a spike in demand?

Regulators say Britain’s electric grid may have to permanently reward customers for using less energy at peak times in order to reduce its dependence on coal. Octopus Energy called for the National Grid to introduce a permanent scheme to reward customers for using less energy at peak times in order to reduce dependence on coal. Nearly 700,000 Octopus smart meter users received £5.4 million ($6.8 million) under its Savings Session trial over winter, where customers were paid to use less power than they otherwise normally would during peak times. In total, Octopus said its scheme shifted 1.86 gigawatt hours of electricity demand to times of less stress on the network – the equivalent of stopping two million washing machine loads. According to Octopus, rolling out the system across Britain would reduce the cost of the National Grid’s coal contingency by about three quarters, from £340 to 395 million ($430 to $500 million) last winter to just £106 million ($134 million).

Britain is putting its electricity system in the hands of renewable power generators as it closed its nuclear power plants last year. As gas supplies remain extremely tight in Europe this year with less supplies from Russia, more of Britain’s electricity is coming from intermittent wind and solar power, posing challenges for balancing the grid and keeping the lights on. Asking consumers to reduce power during peak periods, is moving toward a third world electricity supply, and not an option that a major economic power should be undertaking.


Britain had to turn to a coal plant to keep the lights on during a recent heat wave where its solar power’s efficiency was reduced. Britain plans to shutter its backup coal plants by October 2024 as it relies on intermittent wind and solar power with whatever tight natural gas supplies it can get due to Russia’s invasion of Ukraine. As Britain shutters its coal-fired plants, regulators indicate that Britain’s electric grid may have to permanently reward customers for using less energy at peak times because its backup power from coal will no longer be an option—a result of reducing its dependence on coal, even as a backup power source, to reach net zero carbon emissions.

Not having enough backup power reeks of potential blackouts if consumers do not comply. And, asking consumers to reduce their electricity demand during peak periods could be the start of power rationing that could lead to a third world power supply situation. It is a particular irony of our times that Britain, who first used coal to create the Industrial Revolution, now finds itself scavenging for enough electricity to keep its lights on as it contorts to a self-imposed scarcity of energy owing to its adherence to the Paris Accords.

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