Crowdflex, described by Scottish and Southern Electricity Networks Distribution as the largest domestic flexibility study ever undertaken in the UK, published its findings on 10 January 2022. The project, run with National Grid ESO, Octopus Energy and Ohme, examined how 25,000 households responded to price signals by reducing or increasing electricity demand1.
The study tested two kinds of signal. Enduring signals came from customers who moved from a flat tariff to a time-of-use (ToU) tariff. One-off signals asked customers to sign up to a "Big Turn Up" or "Big Turn Down" event and rewarded those who changed their demand over a specified two-hour period1.
Customers on ToU tariffs reduced their demand during the evening peak by 15 to 17 per cent and maintained that reduction over six months. Households with an electric vehicle showed a greater ability to flex, achieving reductions of up to 23 per cent in the proportion of a household's daily demand consumed during the evening peak1.
Responses to the one-off events were also significant and strongly affected by EV ownership1.
| Signal | EV households | Non-EV households |
|---|---|---|
| Big Turn Up: increase in average evening peak demand | 617% | 131% |
| Big Turn Down: reduction against average evening peak power demand | -59% | -41% |
The report notes that electricity demand is predicted to approximately double according to National Grid ESO's Future Energy Scenarios, and that measures which manage demand and help balance the grid will be needed for a cost-effective net zero transition1. Crowdflex is funded jointly by National Grid ESO's and SSEN's Network Innovation Allowance1.
"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."
Why it matters for households
Flexibility is the ability to shift the timing and location of both the consumption and generation of electricity1. For a household, the study's numbers describe how much of a home's evening electricity use can move to other hours when a price signal or an event reward makes it worthwhile. The ToU result is the more durable of the two: a 15 to 17 per cent cut in evening peak demand held for six months, which is the pattern a household would see on a time-of-use tariff rather than in a one-off event.
The gap between EV and non-EV homes runs through every result. EV owners cut a larger share of their evening peak demand and responded far more strongly to both turn-up and turn-down requests, which the report links to a willingness in those households to offer EV assets for flexibility1. Homes without an EV still responded, but by smaller margins.
The scale of the effect matters beyond the individual bill. SSEN Distribution delivers power to over 3.8 million homes and businesses across central southern England and the north of Scotland1, and the distribution networks that carry household demand are covered in our guide to electricity distribution networks. If demand at peak can be trimmed by household action, that changes what the grid has to build for as electricity demand grows with EVs and heat pumps. The wider picture of how household demand flexibility fits into system operation sits under national supply.
What happens next
The project partners say they hope to undertake future trials to investigate the reliability, consistency and cost of domestic flexibility1. No dates, funding amounts or participant numbers for any further phase have been reported.