March 09, 2023

Insights from the UK's Largest Consumer Energy Flexibility Trial


Centre for Net Zero


The Demand Flexibility Service of Winter 2022 - 2023 saw over one million households participate and support the grid during times of strain. This summary of early analysis explores the behaviours of those who participated, and the impact of price, communications, weather and household type on engagement with the trial. It provides a series of recommendations that will enable the UK to operate domestic flexibility at scale, which is critical to successfully decarbonising our energy system and hitting net zero.

Key findings

① Demand flexibility can have a significant impact on the grid at all times, but especially at periods of strain on the grid
The trial delivered system-level impacts: 2.92GWh of energy was shifted from peak periods, and 100% of the grid’s requirement when it was under strain was met by consumers.

② Households are receptive to changing their energy consumption and can make savings on bills
Altering price signals, notice periods and communication techniques influence the amount of flexibility we can expect from households.

③ Weather doesn’t deter households from turning down their energy use
Opt-in rates on cold winter days were similar to mild and warm winter days. Greater per-household electricity reduction occurred on the coldest days, on average.

④ Even with short notice, households are able to provide flexibility
Households can be relied on intraday (i.e within 6 hours notice of an event) if required. There is a trade-off between notice period and price. Customers with low carbon technologies find it easier to respond at shorter notice, but all households are capable of doing so.

⑤ Household flexibility is largely manual at present – automation is key to scaling it up in the future
75% of survey participants said they manually switched off appliances, rather than scheduling them to run at different times.