How heat batteries can shift demand peaks from electric heating

Heat batteries functioning as an all-electric low-carbon alternative to fossil fuel boilers can shift peak energy demand for heating to off-peak times by up to 95%, an innovation trial in the UK has found.

The trial, Neat Heat, led by UK Power Networks in partnership with energy supplier OVO and tech developer tepeo, ran for 18 months until June this year.

The project saw tepeo’s Zero Emission Boiler (ZEB), which uses heat battery technology, installed in 30 homes across the South East and East of England.

The findings demonstrated that such heat batteries can shift peak energy demand for heating to off-peak times by up to 95%. This means that homes could be efficiently heated during the lows of winter, while providing carbon savings of 15,600kg CO2, compared to if these homes were using gas boilers instead.

According to UK Power Networks in a release, by leveraging thermal storage, homes could ‘charge’ their heating systems outside of the most expensive hours of the day, with heat being released on demand when needed.

The British DSO adds that, at launch, the project attracted more than 2,000 registrations of interest for the limited spaces available, suggesting a strong demand from UK customers for new alternatives to fossil fuel heating.

Commenting in a release was the CEO of tepeo, Johan du Plessis: “Neat Heat’s success paves the way for the wider deployment of heat batteries, which is critical to the UK’s successful transition to net zero.

“Heat batteries working in tandem with dynamic tariffs will enable millions of homes currently unable to switch to low-carbon solutions to join the green transition.”

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The Heat Neat trial was built around a tariff proposition developed by OVO called a ‘type of use’, giving customers access to a cheaper (than standard) rate to charge their ZEBs. Customers could also set their ZEBs to charge during the cheapest times during the day, making it simple for the customer and enabling flexibility for the grid.

As well as showing 95% of a trialist’s yearly heating demand could be moved outside of peak hours, where demand on the grid was highest, over 90% could be moved in the coldest weeks in winter. All participants experienced no noticeable change to their heating, with the ZEB providing a similar experience as a traditional boiler, but powered entirely by electricity.

UKPN calls the heat batteries an ideal technology for the estimated over 20% of UK homes that lack the space required for low carbon solutions like heat pumps or where these solutions could prove difficult to retrofit.

UKPN adds that installation of the ZEB took on average between one and two days and that all trialists opted to continue with their new ZEB heating solution, rather than reverting to a fossil fuel boiler.

Head of Innovation at UK Power Networks, Luca Grella, said: “Being able to move electricity demand away from peak hours is huge, for both our network and customers.

“The more people move to electric heating systems, the more resilient our network will need to be. Shifting demand away from peak hours will reduce the upgrades needed to keep up with the future demand of green technologies, which would ultimately have been paid for by customers across the country. We hope this also opens the door to further low carbon solutions which we know they are keen to adopt.”

Grainne Regan, head of heat at OVO, added: “The ability to decouple electricity consumption from heating is an essential part of decarbonising home heating. This trial represents a huge step forward in our joint mission to decarbonise the UK energy grid by 2035.

“We’re committed to making it easier for our customers to access energy that is better for them, their wallets and the planet, and this trial is a great example of how we are delivering on that.”