It is a Government scheme to help people getting the Guaranteed Credit element of Pension Credit with their winter energy bills. (Other vulnerable people on a low income may also be eligible, but will have to apply to their electricity supplier. See the fact sheet below for more detail.)
If you are eligible you get a one-off discount of £140 on your electricity bill between October and April. The discount won’t affect your Cold Weather Payment or Winter Fuel Payment.
Even better, if you are one of the people getting the Guaranteed Credit element of Pension Credit you don’t actually have to apply for it. If you get your electricity from one of the suppliers that are part of the scheme they will contact you to let you know that they think you are eligible and whether you need to do anything more to get the money.
Read more about the scheme on the GOV.UK web site, or download the fact sheet below.