The Warm Home Discount is a government backed scheme, where you can get up to £140 discount off your electricity bill over winter. There are two groups under the Warm Home Discount, the core group and the broad group. The core group is made up of anyone who receives guaranteed government pension credit. If you’re part of this group you should select ‘Warm Home Discount’ during your signup so that we can ensure that your new supplier is signed up the scheme. You can find out if you’re eligible for the broader group by contacting your supplier. Suppliers can at times offer this on a first come first served basis and as such if you are part of the broader group we cannot guarantee that you will receive this. 

You can find more details on the government website here: https://www.gov.uk/the-warm-home-discount-scheme/low-income