Methodology for the Supply Market Indicator


Publication date

Industry sector

Supply and Retail Market

To make the energy market clearer for consumers, and to help them understand the outlook for the different costs that make up their energy bill, we publish a monthly Supply Market Indicator (SMI).

This is a commentary on recent and possible future cost trends suppliers face and how they change over time. It also estimates the annual:

  • bill for average domestic gas, electricity and dual fuel customers
  • cost per customer a large supplier incurs to deliver gas and electricity.

The SMI can only ever be viewed as an estimate, in part, because we do not forecast retail prices and we assume seasonally normal weather over the next 12 months.

This is our methodology which explains the approach we have taken to produce the trend estimates.

Subsidiary documents