Key terms and issues explained

Mae’r dudalen yma ar gael yn Gymraeg.

On this page you will find a range of key terms explained for business energy. Please click on a letter below to be taken to a list of terms and on "show" to read the explanation.

Dead tariff

A tariff in respect of an evergreen contract which is no longer capable of being entered into by all domestic customers.

Deemed Contract

A contract where a customer takes a supply of electricity, gas or both in a manner otherwise than under a contract that has been expressly entered into with a supplier.

Department for Energy and Climate Change (DECC)

The UK government department responsible for policy in the fields of energy and climate change.


An exemption from or relaxation of a rule (which may include the imposition of alternative rules).


A determination is a binding decision by us, including our reasons, in relation to a dispute referred to us under the Acts or the relevant licence provisions.

The circumstances in which a dispute between a licensed energy network company and a customer may be referred to the Gas and Electricity Markets Authority (“the Authority”) for determination are set out in:  Ofgem guidance on determination of disputes [pdf].

Individual determinations are published on our Electronic Public Register.

Direct debit (DD)

A method of payment where a fixed or variable amount is taken from a bank account each month, quarter or year.


Any form of payment, saving, rebate benefit or reward that is in any way linked to a Domestic Energy Supply Product. One example is the dual fuel discount.

Domestic customer

A customer that uses energy for non - commercial purposes.

Domestic energy suppliers

Companies who sell energy to and bill domestic customers in Great Britain.

Dual Fuel (DF)

A type of energy contract where a customer takes gas and electricity from the same supplier (or two affiliated suppliers).