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.

Market Segmentation

The process of splitting customers, or potential customers, in a market into different groups, or segments.

Market Share

The proportion of total customers (usually as proxied by the number of meter points) within a market that are registered to a particular supply group.

Medium user

A consumer who annually uses 3.300 kWh of electricity and/or 16.500 kWh of gas.

Meter reading

A meter reading based on the actual amount of energy you’ve used.

Micro business consumer

A non-domestic consumer is defined as a micro business if they meet one of the following criteria:

  • employs fewer than 10 employees (or their full time equivalent) and has an annual turnover or balance sheet no greater than €2 million; or
  • uses no more than 100,000 kWh of electricity per year; or
  • uses no more than 293,000 kWh of gas per year.

A business using 100,000 kWh of electricity or 293,000 kWh of gas should typically pay around £10,000 - £12,000 a year for each fuel (excluding VAT and Climate Change Levy)



Mutual variation

An amendment to the terms and/or conditions (including price, but excluding contract duration) of a consumer’s energy supply contract, mutually agreed between the supplier and the consumer. The consumer would not be obliged to accept the proposed variation. The variation can only be binding following express agreement from the consumer.


A megawatt hour. Equal to 1000 kWh.


A megawatt hour. Equal to 1000 kWh.