Run the dishwasher, plug in the car: how Great Britain plans to use record wind and solar power

Great Britain is on the brink of a record-breaking summer for renewable energy, which could lead to the first periods of zero-carbon electricity in the history of the power system.

These green milestones are an important step towards the government’s goal of creating a 95% gas-free grid by 2030 to power the electric vehicles, heat pumps and greener factories that will help the UK to reach its climate goals.

But in the meantime, the national energy system operator (Neso) expects that during some periods – on a sunny weekend afternoon, for example – there could be more renewable energy available than the electricity grid needs.

Its answer? Calling on homes and businesses to use more renewable energy when it is available by charging their EVs, running their dishwashers or putting on a load of laundry.

The system operator plans to work with energy suppliers to incentivise households to shift energy-hungry activities they would have done anyway to periods when renewable energy is abundant.

The country’s biggest energy suppliers – Octopus Energy and British Gas – have confirmed to the Guardian that they plan to take part.

This could mean discounted energy for customers, and that the system operator can avoid paying wind and solar farms to turn off to prevent overloading the electricity grid, or at least reduce the cost of these payments.

In short: the plan is to use the summer’s record renewables better.

So we have too much renewable energy? No. Renewable energy provided 44% of the UK’s electricity last year and there is still a long way to go to meet the government’s plan to double onshore wind, triple solar power and quadruple offshore wind by the end of the decade.

These targets are needed to ensure there is enough electricity to power the electrification of the economy in the future. But to date, the rollout of heat pumps and electric vehicles has not been as quick as the pace of the UK’s renewable energy growth.

Grid upgrades have also slowed the progress in building clean energy projects. There are bottlenecks in the grid, which mean some areas – particularly in Scotland – can easily become overloaded with renewable energy, with no way to transmit the electricity to other areas that need it.

Grid upgrades and increasing electrification will help reduce periods of surplus renewables. Building more batteries to store wind and solar power for when it is needed is another solution. But simply using more renewable energy when it is available is cheaper than infrastructure investments – and it is available to most households.

What can households do to help? More than 2m homes across Great Britain are already playing a role in making better use of renewable energy by fitting a smart meter and signing up to tariffs that offer discounted energy when electricity is abundant, helping to make use of renewables and cut costs.

One such tariff is the British Gas “PeakSave” scheme, which encourages customers to use electricity when there is an abundance in the system, or when there is lower demand. Customers who have opted in to the scheme receive half-price electricity from 11am to 4pm on a Sunday, when energy demand is usually low, or they can sign up to a “Super Sunday” tariff for even more half-price electricity, between 9am and 5pm on a Sunday.

The supplier estimates that it has saved more than 1 million customers at least £45m on their electricity bills since it launched in 2023. Other suppliers offering a similar deal include Octopus Energy, Ovo Energy and EDF Energy.

Octopus estimates it has helped 2m households to save about £11m with its early schemes, which paid customers to cut their energy use during periods of high demand. It had saved customers about £3m by offering free electricity during periods of high renewable energy so far, the company said.

Suppliers also offer so-called “time of use” tariffs, which offer different rates for different periods of the day, usually including far higher rates when renewables are scarce and demand is high – a still, wintry late afternoon, for example, would be an expensive time to charge a car, but waiting until the middle of the night would be cheaper. For those who can shift their energy use, the tariff can offer savings.

What are the benefits of flexible energy use? For households, the savings on their energy bills are a key benefit. But there are other gains from making better use of Great Britain’s renewable energy resources.

Using renewable energy when it is abundant means the system operator is less likely to need to pay wind and solar farms to turn off when demand is low. These so-called constraint payments are ultimately paid for through home energy bills and are understood to have reached almost £1.5bn last year. From this summer the system operator is expected to rely on households to “turn up” before it resorts to payments for renewables to “turn down”.

Households could get cheap electricity if they charge their EVs overnight. Photograph: John Walton/PABy shifting demand to periods when there is a surplus of electricity available, consumers can effectively lower the demand highs reached during peak periods, when gas-fired power plants are often used to top up supplies.

Cutting the UK’s use of gas is a key focus for the government because it is often the most expensive source of electricity and sets the market price at a far higher level – especially since the global energy supply crisis triggered by the war in Iran.

Can businesses play a role, too? Yes. Businesses have been keen adopters of demand flexibility.

Those that can shift energy-intensive processes away from peak demand periods will often do so to save money. They can schedule key processes for times that are typically lower in demand, or switch to use their own on-site energy sources, such as batteries, during peak demand periods.

Tech companies claim that by using energy flexibly, even energy-hungry datacentres can cut grid costs by up to 5% while reducing emissions by as much as 40% by moving key processes to times of lower demand.

The Danish engineering solutions company Danfoss estimates that if datacentres operated flexibly even 1% of the time, the full pipeline of new datacentres expected by 2035 could be connected without overwhelming the grid.