Octopus Energy, OVO Energy, British Gas and E.On will pay customers not to use electricity and help avoid blackouts this winter.
National Grid's scheme is designed to encourage customers to switch the time that they use electricity to off-peak hours during some days when supply is tight. Most customers use electricity at similar times, with a particularly big spike in the evening when people get back from work, start cooking and switch the TV on.
Several companies have either signed up to the National Grid's scheme or created their own.
