That depends on your situation and the type of energy contract you currently have.
If you have a fixed-term energy contract and the end date is not near, it’s usually best to take your contract with you to your new address. If you still want to switch providers, you may have to pay a cancellation fee. You can always request the exact amount of this fee from your energy supplier. This information is usually also available in your online customer account.
If you have an open-ended contract, such as a variable or dynamic contract, you can either transfer your contract to your new home or switch to a new contract free of charge.