Centrica, the owner of British Gas, plans to use its customers’ hot water tanks to create a virtual power plant which could help National Grid prevent future blackouts.

The UK’s biggest energy supplier hopes to harness household gadgets with energy capacity equivalent to a large power plant by 2025. The plan could help to balance the energy system without any perceptible impact for British households.

Centrica said it has developed sophisticated software algorithms to harness thousands of smart appliances to respond when the energy system is under stress.

These devices will automatically use electricity when there is ample renewable energy on the grid, and then pause their energy use when National Grid needs help steadying the energy system.

Similar schemes have already begun pooling the energy potential of supermarket freezers and electric vehicle batteries, but this is the first time that home devices will help balance the grid too.

Centrica’s innovation arm said National Grid had approved its plans to use home water tanks, built by a tech startup from Oxford University, alongside larger industrial equipment to deliver services that could automatically balance the electricity system.

Charles Cameron, the chairman of Centrica Innovations, said the software could help homes save money by using electricity when it was at its cheapest and automatically responding at times of stress without any loss of efficiency or comfort for customers.

The home devices will be aggregated alongside Centrica’s existing flexible power supplies, totalling 2.5GW of electricity capacity, mostly from business and industrial customers.

Mixergy, the tech company behind the smart hot water tanks, said the technology will help consumers use less energy.

The tank uses artificial intelligence to learn how much hot water a household uses, and at which times of day, to make sure that it doesn’t waste energy when hot water is unlikely to be needed.

Pete Armstrong of Mixergy said the technology could pave the way for new energy tariffs, which would “reduce energy consumption and carbon emissions by storing excess renewable energy on the grid”.

“At the same time, we reduce bills for householders by only heating the amount of hot water they require,” he added.

Centrica has rolled out around 100 smart water heaters since June this year, but within the next six years it hopes to grow its stable of fast-response devices to 1GW.