This depends on your current tariff terms and conditions, as well as your contract status. Some tariffs simply don’t have exit fees, and that’s a selling point used to make them more appealing. Your current supplier will be able to tell you if you have any exit fees to pay for leaving.
The type of energy tariff you are on can determine whether or not you pay any exit fees when switching your energy supplier, too. If you’re on a standard variable tariff you can switch without incurring any fees, however, if you’re on a fixed term plan you’ll most likely be charged when leaving your current supplier. Although, when you receive your notice 49 days before the end of your fixed-term tariff, suppliers cannot charge a termination fee if you choose to switch after this point.
Sometimes cancellation fees are dependent on your supplier, too. There are now some energy suppliers out there that have chosen to completely scrap cancellation fees, giving them an advantage over the ones that do.