Octopus Energy, Great Britain's largest household energy supplier, is calling on its customers to reduce electricity consumption during Wednesday's solar eclipse, the deepest in nearly three decades. The company has urged households to avoid running washing machines and dishwashers between 6pm and 8pm, as the moon is expected to block up to 95% of the sun over parts of Britain.
The eclipse is forecast to wipe out the last of the day's solar power generation, coinciding with the country's fifth heatwave of the year, which is likely to increase demand for air conditioning, fans, and refrigeration. In return for shifting usage, Octopus is offering customers enrolled in its rewards program a free hour of electricity to use the following weekend. The offer applies to those signed up for "saving sessions," where households earn rewards for using more electricity during times of renewable abundance or less when wind and solar power are scarce.
Potential impact on grid and customer incentives
Octopus believes that if enough households delay electricity use for a short period, it could reduce the need for the electricity system operator to activate additional gas-fired stations to compensate for lost solar power. "Household flexibility is one of Britain's biggest untapped energy resources," the supplier stated. "Octopus estimates homes could provide a whopping 13 gigawatts of flexible capacity to support the electricity system – particularly through smart appliances, EVs and home batteries – yet only a fraction of this potential is currently being used."
The National Energy System Operator (Neso), responsible for running Great Britain's electricity system, said it had been "planning for over a year" to manage the eclipse's effects, describing it as "one of the most unusual evenings our control room will manage this year." Neso expects the daily early evening peak in electricity demand to occur later than usual, as millions head outdoors to watch the eclipse before returning home to cook, clean, and watch TV.
Heatwave and European power strain
The ongoing heatwave has already forced Neso to issue its first summer warning notice for electricity supplies in late June. Soaring temperatures lifted demand while disrupting generation due to low wind speeds and power plant outages across Europe. The solar eclipse is expected to wipe out 9.7GW of power production across Europe between 7.15pm and 9.30pm at its strongest point. In the UK, this could mean losing between 700 megawatts and 1.3GW of solar generation, while in Spain, solar power could be reduced by up to 5GW, according to the country's system operator.
Analysts at RBC Capital Markets warned that this would "pile pressure" on Europe's already "tight" power system. Heatwaves have forced nuclear and coal plants to lower output or shut down entirely across Europe due to reduced river water levels needed for cooling. The drought has also affected hydropower reservoirs in Norway, a leading exporter of electricity to continental Europe, which have reached their lowest levels in 30 years.
Expert and company responses
Rebecca Dibb-Simkin, Octopus's chief customer officer, said: "Many of us will be looking up at the sky on Wednesday evening to experience this once-in-a-generation event. But as the sun disappears, so will some of Britain's solar generation, just as demand peaks. By shifting everyday tasks like the washing machine or dishwasher until later, households can help reduce the need for gas power stations – and earn rewards for doing their bit."
Neso is also facing scrutiny over its grid management after control room whistleblowers accused senior executives of covering up instability in the energy system for political reasons. In late June, it was forced to abruptly cut planned exports of electricity to the Netherlands via the high-voltage BritNed interconnector and call in emergency imports from a large power cable to France after the grid's frequency fell to the edge of its operating limits.
