The UK is facing an energy crisis as wholesale prices for gas soar, putting 11 suppliers out of business.
It means it will be harder for the poorest families to pay their bills and there are warnings that the high prices are here to stay for the long term.
The price of wholesale gas has surged by 250% since the beginning of the year and has risen by 70% since August, according to figures from Oil & Gas UK.
It has been blamed on a number of factors, including a cold winter which left stocks depleted, high demand for liquefied natural gas from Asia and a reduction in supplies from Russia.
Boris Johnson blamed the emergence from the Covid-19 pandemic.
With a number of energy companies folding amid the crisis in the UK, what does it mean for the customers of those suppliers?
Which energy suppliers have gone bust this year?
Simplicity Energy - January 27 - its 50,000 customers had been taken over by British Gas Evolve
Green Network Energy - January 27 - its 360,000 customers had been taken over by EDF
Hub Energy - August 9 - its 15,000 cusotmers had been taken over by E.ON Next
MoneyPlus Energy - September 7 - its 9,000 customers have been taken over by British Gas
PFP Energy - September 7 - its 87,600 customers have been taken over by British Gas
Utility Point - September 14 - its 220,000 customers have been taken over by EDF
People's Energy - September 14 - its 351,000 customers have been taken over by British Gas
Green Supplier Limited - September 22. Shell Energy is to take on 255,000 former customers
Avro Energy - September 22 - Octopus Energy to take on Avro’s 580,000 customers after the supplier collapsed
Enstroga- September 29 - E.on Next took on the company's 6,000 domestic customers
Igloo Energy- September 29 - its 179,000 domestic customers were moved to E.on Next
Symbio Energy- September 29 - E.on Next also picked up Symbio Energy's 48,000 domestic customers
Colorado Energy- October 13- Ofgem assured its 15,000 domestic customers that their energy supplies would continue under its safety net
Pure Planet- October 13- Ofgem assured its 235,000 domestic customers that their energy supplies would continue under its safety net
Daligas - October 15 - Ofgem has said it will protect 9,000 customers’ supply of energy and credit in accounts.
Which energy suppliers are in danger of folding?
Other struggling firms that have been named in reports include Zebra Energy, Ampower and Neon Reef.
Together, these companies supply energy to hundreds of thousands of customers.
What should you do if your energy supplier goes bust?
Ofgem has advised customers to take a meter reading and not to switch suppliers immediately as the energy watchdog will eventually move you to a new supplier.
This way, your new supplier can tell you what to do about any credit balances you might have had with your old supplier. But you may cancel your direct debit if you want to.
In the transition period where you may not have a supplier, your supply will not be disrupted and you will still have electricity and gas in your home.
Your new supplier will then contact you, and you should ask to be put on its cheapest tariff. If you are not happy with the new deal, you can then shop around. You will not be charged exit fees.
Your new supplier will also explain how they will manage your account balance, including any credit refunds. If your previous energy supplier owes you money, your money is protected and you should get it back.
Money Saving Expert Martin Lewis told ITV that it could be a "pain in the backside" to get back credit from providers which have folded but that "it will happen eventually".
Businesses' credit balances are not protected under Ofgem's safety net. What should they do?
Business customers should contact the company’s administrator to ask them what to do about their credit balances.
Will your bills go up?Probably, especially if you were on a cheap deal that was not run in a sustainable way.
Your new supplier will initially put you on a specially 'deemed' contract, which means a contract you haven't chosen.
Deemed contracts can be more expensive because the supplier takes on more risk. For example, they might have to buy extra wholesale energy at short notice.
However, you can switch to a cheaper rate once your supplier contacts you.
Earlier this month, Boris Johnson said families will not struggle this winter because energy issues are 'short term'
Will the credit balance from your old supplier be protected if you are switching supplier already?
Once you have switched, your direct debit with your old supplier should be cancelled. If it hasn't been cancelled, you may need to close it off yourself.
Ofgem says it will look to appoint a supplier who will pay back money owed to you.
Will you still need to pay back debt you owed to your old supplier?It depends on the agreement between your old and new supplier.
You may have to continue to pay your debt to your old supplier or their administrator, or you may have to pay your debt to your new supplier if that arrangement has been made.
How do energy suppliers work in the UK?
Supplying energy to homes involves three steps: generating the electricity, transporting the gas and electricity and selling it to customers. Energy companies can work in any of these stages.
In the UK, private companies make sure we have the electricity and gas markets that we need.
Electricity is generated in power stations, which are run by private companies.
It is then transported through the electricity network run by National Grid.
Suppliers buy energy in the wholesale market and sell it on to customers.