Second National Grid heat pump trial launches


19 December 2023

National Grid has kicked off the second stage of award-winning EQUINOX project after recruiting over 1000 customers.

During the first EQUINOX innovation project trial, almost 400 households provided a total measurable household turndown of 10.8 MWh - the energy needed to make more than 300,000 cups of tea.

Heat pump flexibility can help to lower customer energy bills and reduce peak electricity consumption on the electricity network – these are the findings from stage one of National Grid Electricity Distribution’s Ofgem Network Innovation Competition (NIC) funded EQUINOX innovation project. The Equitable Novel Flexibility Exchange or ‘EQUINOX’ project aims to save consumers money by using flexibility services to cut energy bills and deliver a resilient and equitable low carbon energy system.

Working with project collaborators including Octopus Energy, Scottish Power and Sero, National Grid is developing new commercial and technical arrangements to unlock flexibility from residential low carbon heating, as part of its role as Distribution System Operator (DSO). It is doing this while still meeting the needs of all consumers, including the fuel poor and those in vulnerable situations. The project began in December 2022 and is planned to run until December 2025. The second stage of the trial was launched this November.

 Following the successful first trial, EQUINOX won the award for Heat Pump Project of the Year – Domestic Innovation at this year’s Heating and Ventilation News Awards. EQUINOX was also nominated at this year’s Utility Week awards.

 Last winter, 386 heat pump owners across National Grid’s distribution licence areas in the Midlands, South West and South Wales took part in the unique trial, turning off their heat pumps for 22 two-hour periods between 5 - 7pm, in exchange for savings on their bills over the trial period.

During the trial, households provided a total measurable household turndown of 10.8 MWh - equivalent to the energy needed to make more than 300,000 cups of tea. Feedback from customers was overwhelmingly positive: 92% of participants were moderately or extremely satisfied with their experience of the first trial.


Matt Watson, Head of Commercial and Operability at National Grid DSO, said: “The initial results from our EQUINOX trials show that heat pump flexibility can help manage the demand on electricity through the distribution network while simultaneously saving customers money on their energy bills.

“Feedback from participants so far have shown that these kind of flexibility measures do not compromise the comfort of households and that the customer experience was positive.

“As thousands more homes switch to heat pumps, flexible systems like this are going to be even more crucial to balance demand at key times. Trials like EQUINOX show that customers are willing to tweak their everyday lives to save money and help balance the system.”


As with the first trial, the second trial was open to any Octopus Energy, Sero and ScottishPower customers with heat pumps connected to National Grid’s distribution network in the East or West Midlands, South West or South Wales.

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For more detail on all things EQUINOX you can visit the project website at:


What our project partners said:

Andy Sutton, Chief Innovation Officer and Co-Founder of Sero, said: “Grid interactions such as demand-side response are intrinsic to successfully delivering net zero. Doing this without impacting resident comfort whilst simultaneously reducing energy bills further demonstrates the positive impact of harmonising our homes’ ability to align energy demand to the grid’s delivery capacity.

 “We’re thrilled with the results from EQUINOX’s first trial which spanned four months over the 2022/23 winter period. By reacting to signals from National Grid, heat pumps were turned off remotely by Sero’s Building Energy Engine (BEE) providing a total of 630 hours of flexibility. Sero had an impressive 100% participation rate, with no opt outs throughout the entire trial.”


Alex Schoch, Head of Flexibility at Octopus Energy, said: "By offering real monetary benefits to customers who can flexibly use their heat pumps, we have been able to prove that homeowners can get involved with helping the local energy system while saving money - all without impacting their day to day lives. Boundary pushing technology projects like Equinox will help lower grid costs across the board and help move the whole country over to a clean, green energy system."


Rob McGaughey, Head of Smart Heat and Cities at ScottishPower, said: “Cleaner heating is vital to tackling climate change and heat pumps are increasingly recognised as crucial to decarbonise our homes. As a company, we’re playing our part by deploying heat pumps in homes across the country, having installed over 1,000 this year alone. We are delighted to offer our customers the ability to unlock the additional benefits of flexibility this coming winter as part of National Grid’s excellent EQUINOX heat pump innovation project.”


Other project collaborators include SP Energy Networks (SPEN), PassivUK, Welsh Government, West Midlands Combined Authority (WMCA), Guidehouse and National Energy Action.