The energy regulator, Ofgem, said 9,000 Gnergy customers have been moved to Bulb following a “competitive process to get the best deal” for them. The move comes after Gnergy collapsed last week.

All outstanding credit balances will be honoured, including money owed to both current and existing customers of Gnergy. Ofgem added that Bulb will absorb all of the costs of honouring customer credit balances and during the migration process.

Current and former customers who owe money, or are in debit to Gnergy should wait to hear from Bulb or Gnergy’s administrators.

For existing customers, energy supply will continue as normal but they will be contacted over the coming days about the changes.

If customers want to switch supplier they should shop around. They won’t be charged exit fees if they decide to switch to another supplier.

Philippa Pickford, Ofgem’s director of future retail markets, said: “I am pleased to announce we have appointed Bulb for the customers of Gnergy. Their energy supply will continue as normal and credit balances will be honoured.

“Bulb will be in contact with customers over the coming days with further information. Once the transfer has been completed, customers can shop around for a better deal if they wish to.”

Bulb is a renewable energy supplier with more than 1.6 million customers in the five years it has been trading. It said for Gnergy customers switching to it, many will see a significant price drop.

Hayden Wood, co-founder and CEO of Bulb, said: “We’re delighted Ofgem has chosen Bulb to provide energy for Gnergy’s customers. It’s important that everyone has a reliable energy supply, especially during a time like this. I’m proud of how quickly our team has adapted to remote working in order to keep supporting our members. We’re excited to welcome our new members, and look forward to helping them cut their bills and reduce their carbon emissions.”