Domestic flexibility could cut peak demand by 6.8GW by 2030

The UK’s largest ever study into domestic flexibility has suggested it could reduce peak electricity demand by as much as 6.8GW – or 10% – by 2030.

The CrowdFlex project involving Scottish and Southern Electricity Networks (SSEN), National Grid Electricity System Operator (ESO), Octopus Energy and Ohme, explored how 25,000 households responded to price signals to reduce or increase their consumption.

The project analysed the impact of enduring prices signals provided to 18,000 customers on Octopus Energy’s static time-of-use tariff, ‘Go’, that offers cheaper electricity (5p/kWh) between 00:30 and 4:30 each day, and almost 2,400 customers on its dynamic time-of-use tariff, ‘Agile’, that tracks wholesale market prices during each half-hour settlement period.

It also looked the impact of one-off signals to customers, who were rewarded for raising or lowering their demand during specified two-hours periods. Customers were notified in advance of the ‘Big Turn Up’ and ‘Big Turn Down’ events, which took place at different times of day, with more than 19,200 taking part in the former and almost 400 in the latter.

The final report on the first phase of the project, which analysed data covering a period of six months, stated: “Enduring interventions of customers switching from a flat to a time-of-use tariff proved to be capable of significantly reducing households’ demand during the evening peak and sustaining that reduction over many months.”

It said customers on Octopus’ Agile and Go tariffs reduced the proportion of their daily electricity demand consumer during the evening peak hours by averages of 15% and 17% respectively.

The response was greatest for electric vehicle (EV) drivers on the Agile tariff who lowered their consumption by an average of 0.2kW between 4pm and 7pm, representing an 18% reduction in their average demand and a 23% reduction in the proportion of their daily demand consumed during the three-hour period.

The average reduction was also 0.2kW for EV drivers on the Go tariff, although this represented a smaller 17% reduction in their average demand and a 19% decrease in the proportion of their daily demand consumed during the time slot.

The reduction from other households on the Agile tariff was 0.1kW, equating to a 7% reduction in average demand and a 12% reduction the proportion of their daily demand consumed during the evening peak. There was no overall response from households without an EV on the Go tariff.

The difference between EV and non-EV households was even more pronounced for customers participating in the ‘Big Turn Up’ events, with the former raising their demand by 5.8kW on average – a 617% increase when compared to the baseline for the evening peak – and the latter raising their demand by 1.5kW on average – an 131% increase over the baseline.

There was far less difference for customers participating in the ‘Big Turn Down’ events, with EV drivers lowering their demand by an average of 0.6KW – or 41% – and non-EV households lowering their demand by 0.5kW – or 59%.

Extrapolating the results of the trial to the whole of Great Britain suggested domestic flexibility could reduce peak demand on the power grid by 6.8GW – or 10% – by 2030 in a high scenario in which there is widespread adoption of EVs (38%) and high rates of participation (up to 63%). In this scenario, households could also offer a whopping 37GW of demand turn-up.

However, in the low scenario in which EV uptake is limited (14%) and there is low participation (10%), households would only provide 400MW of demand reduction, equating to just 1% of peak demand.

Matthew Hamilton, CrowdFlex project manager for SSEN, said: “Flexibility will play a key role in the future smart electricity system and we are committed to ensuring that all customers have an opportunity to participate and benefit from offering domestic flexibility services. Helping the communities we serve to engage with the future electricity market will be the cornerstone of a just transition to net zero.

“Establishing that households are willing and able to respond to signals to flex their demand is the first step. We hope to take this work forward by considering practical trials to prove reliability, repeatability and to investigate the costs of domestic flexibility.”

Geoff Down innovation manager at National Grid ESO said: “System flexibility is vital for future system operation and we’re encouraged to see that engaged consumers can, by participating in time-of-use tariffs, help manage and reduce peak electricity demand. With the use of low carbon technologies in the home set to grow rapidly, this project helps us understand the exciting opportunities for us in the future.”

The project is being supported by funding from Ofgem’s Network Innovation Allowance.