Your energy supplier is required to issue you an invoice. They may not charge you for this.

If you refuse an electronic invoice, the supplier may not charge you additional fees for sending a paper invoice. Your energy supplier may, however, give you a discount to encourage electronic invoicing.

If you enter into a contract agreeing to an electronic invoice, you will no longer receive a paper version and you cannot refuse the electronic invoice. Your energy provider must communicate this clearly so that you can give informed consent.

Do you normally receive a paper invoice but suddenly receive an electronic version without your consent? Then you have the right to object.