In order to offer the ​lowest possible rates, we buy the energy we expect you to use in a year or more in advance​. This will depend on the term of the tariff you’ve chosen​. Doing this helps us ​lock in the cost of energy for the period of the tariff and ​allows us to guarantee the price. 

If you choose to leave your contract early, we are left with excess energy that has already been bought​. We charge an exit fee to go some way to cover the cost of the energy that we no longer need.