Skip to content

Insights from the UK’s largest consumer energy flexibility trial


Analysing the behaviours of households that participated in National Grid ESO's Winter Demand Flexibility Service


With National Grid’s 22/23 Winter Demand Flexibility Service now completed, this analysis presents some key findings, including a closer look at the behaviours of Octopus Energy participants as the majority of the one million household who participated.


The trial saw over one million households participate and support the grid during times of strain between November 2022 and March 2023. 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

  • 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. 
  • 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. 
  • 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. 
  • 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. 
  • 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. 

Check out the full slide deck on the right hand side. We will be releasing a more detailed academic paper in due course on the Demand Flexibility Service and Octopus Energy’s Saving Sessions.