A special switching deal to help people reduce their energy bills is to be offered to about 50,000 households.
The regulator Ofgem will run a trial – to be launched in the next few weeks – which could offer savings of up to £300 a year for each customer.
It will be based on the idea of “collective” switching, where large numbers of consumers swap supplier in one go.
Eligible customers will have been on a standard tariff for over three years.
About 55% of households are currently on such tariffs, which are the most expensive.
Despite previous incentives to switch to cheaper fixed-term deals, many people have been reluctant to do so.
Ofgem said it had already chosen one of the big six energy suppliers to run the trial, but it has not revealed which one.
It will also appoint a consumer partner to help with the switch – possibly a switching site, or a consumer group.