Around 410,000 energy customers will be moved to new providers after Green Network Energy and smaller firm Simplicity Energy stopped trading.
EDF Energy will be the new supplier for Green Network Energy customers and British Gas Evolve will take on Simplicity Energy's customers.
However, in late January it fell into credit default with the market operator Elexon. This means it didn't have enough credit to cover the cost of trading gas and electricity to supply its customers.
The same has also happened to smaller firm Simplicity Energy, which had around 50,000 domestic customers. Simplicity Energy was offering some of the cheapest gas and electricity deals in recent months.
Customers were moved to their new suppliers on Sunday 31 January. Energy regulator Ofgem chose the new suppliers in a competitive process.
You will be contacted by your new supplier in the coming days about the changes. Your credit balance will be protected.
Your gas and electricity supply will continue as normal while you are transferred to your new supplier.
While you wait for your new supplier to contact you, you should:
Your new supplier will contact you as soon as possible. Ofgem says this will be 'in the coming days'. You'll need to give it your meter reading.
Ofgem advises customers not to switch supplier until you have been moved to your new supplier. This will make the transfer simpler and it easier to pay back your credit balance.
It also asks customers not to cancel their direct debits with their old suppliers. The new suppliers will aim to transfer these and contact you to help you set up your new account.
When the new supplier contacts you, ask to be put on its cheapest deal for you. If it's not what you want, you can then shop around to find a better deal with a different company.
You won't be charged exit fees for switching away from the supplier chosen for you by the regulator.
You will be put onto EDF Energy's 'deemed' tariff rate. EDF Energy will contact you to tell you the exact details.
If you were in credit to Green Network Energy, EDF Energy will honour this. This is likely to be added onto your EDF Energy account once it is set up.
Customers who switched away from Green Network Energy and were owed a refund will be paid this by EDF Energy.
Around 12,000 Green Network Energy customers are still owed their £140 Warm Home Discount payment. EDF Energy will also make these payments to eligible customers.
If you paid Green Network Energy by direct debit, don't cancel it as EDF Energy aims to transfer it. EDF will be in touch to explain how to set up your new account.
British Gas Evolve is a small brand run by British Gas. It offers online-only customer service and 100% renewable electricity.
If you had a credit balance with Simplicity Energy, British Gas Evolve will honour this. Customers who switched away from Simplicity Energy will get their credit balances back.
If you paid by direct debit with Simplicity Energy, don't cancel it as British Gas Evolve plans to transfer it. It will be in touch to explain how to set up your new account.
If you're in credit with either firm, your balance will be protected. Usually this means that your credit will be added to your account with the new supplier.
If you have switched away from the closed energy firm, or are in the process of doing so, you'll need to wait until a new supplier has been appointed to get your credit back. Often, the new supplier will pay this back by cheque.
Both of these processes can take several weeks. This is because the new suppliers need to look through the old suppliers' records. They will deduct any unbilled charges from your old supplier from your credit before they pay it back.
Yes, you will still need to pay money you owed to either closed supplier.
If you owed Green Network Energy money, and were a customer when it closed, then either EDF or Green Network Energy's administrators will talk to you about paying this back.
Customers who owed it money and switched away from Green Network Energy before it stopped trading will also be contacted by either EDF or the administrators.
If you owed Simplicity Energy money, and were still a customer when it stopped trading, then either British Gas Evolve or Simplicity Energy's administrators will talk to you about repayments.
Either British Gas or the administrators will also contact you if you switched away from Simplicity Energy before it stopped trading and owe it money.
If you are owed compensation by Green Network Energy or Simplicity Energy, the new supplier will not pay this. You should contact the administrators of the failed firm, once they are appointed.
If your complaint was with the Ombudsman, it should contact you to tell you what happens next.
If you have a new smart meter (second generation) then it should continue to work the same with your new supplier.
Customers with older smart meters will likely lose their smart functionality when they move supplier. This will not affect your gas or electricity supply.
British Gas Evolve and EDF Energy will upgrade these older smart meters for customers who request it.
Updated: this story was originally published on 27 January 2021 and was updated on the 1 February to include details of the replacement energy suppliers.