British Gas customers on the PeakSave scheme will be able to access half-price electricity on Friday September 12.
The energy company is running a Green Flex event, cutting the price of electricity by 50 per cent between 11am and 1pm.
The event allows customers to carry out high-energy tasks such as charging devices, running washing machines or cooking during the discounted period.
Eligible customers will receive an email explaining how to opt in.
The PeakSave scheme will be able to access half-price electricity on Friday September 12.
|GETTY
Savings will be credited directly to energy bills after participation.
British Gas said the discount is possible because of favourable weather conditions, with wind and sunshine boosting renewable supply across the UK.
The company uses these events to encourage households to shift electricity use to periods when green energy is most plentiful.
The Green Flex sessions are separate from PeakSave Sundays, which already give customers half-price electricity every week from 11am to 4pm.
This regular Sunday discount applies automatically to all PeakSave members.
Many households use the scheme to run appliances or cook during the cheaper hours.
British Gas said the PeakSave programme was designed to help customers reduce costs while supporting the move towards renewable energy.
The company has now launched a new Super Sunday Tariff, extending Sunday savings from 9am to 5pm.
British Gas said the tariff is the cheapest fixed deal currently available from any of the large suppliers.
| PAThis gives customers eight hours of half-price electricity every week, three more than the standard offer.
British Gas said the tariff is the cheapest fixed deal currently available from any of the large suppliers.
Customers will need a smart meter to take part, but switching is straightforward for existing account holders.
The company said the PeakSave scheme has paid out more than £30million since launch.
More than one million households have benefited from shifting energy use to cheaper, greener times of day.
British Gas said: "PeakSave helps households cut their bills and supports Britain’s energy transition by encouraging customers to use electricity when renewable power is most available."
Industry analysts said such flexible tariffs could become more common as Britain increases its reliance on renewable energy.
Energy experts argue that aligning household use with green generation helps balance supply and demand on the grid.
The energy price cap was raised by 2% in October.
| GETTYThey note that high levels of wind and solar power can sometimes outstrip demand during daylight hours.
Discount events such as Green Flex help absorb excess renewable power that might otherwise go to waste.
Supporters say this model reduces reliance on fossil fuels and lowers overall carbon emissions.
Consumer groups are expected to monitor how widely these tariffs are adopted across the energy market.