Energy Company Obligation 2018-22 (ECO3) Guidance: Supplier Administration


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The Energy Company Obligation (ECO) is a government energy efficiency scheme for Great Britain, administered by Ofgem.

Our guidance documents provide information on the legislative requirements of the ECO3 Order and our administrative processes. The ECO3 Order commenced on 3 December 2018 and runs until 31 March 2022.  The ECO (Amendment) Order 2019 came into force on 1 January 2020 and we have updated our documents to reflect this.

Please use version 1.3 for all measures installed after 1 January 2020. For measures installed between 1 October 2018 and 31 December 2019 use version 1.1.

We have split the ECO3 Guidance into two parts.

  1. ECO3 Guidance: Supplier Administration, and
  2. ECO3 Guidance: Delivery.

The Supplier Administration guidance is aimed mainly at suppliers, describing the processes that suppliers and Ofgem follow to meet the requirements of the ECO3 Order. It addresses the following:

  • when a supplier is obligated under ECO3, notifying customer numbers and supply and how  obligations are set
  • details of the solid wall minimum requirement
  • details of the rural sub-obligation
  • how suppliers notify completed ECO measures
  • carry-over and early delivery of measures
  • the application process for trading obligations
  • the application process for transfers and re-elections, and
  • our role as the ECO administrator

For measures installed before 30 September 2018, please refer to our ECO2t guidance Delivery and Administration, Versions 1.1.

Document updated March 2019

Version 1.1 of this guidance includes corrections and updates to the previous version.

Document updated January 2020

Version 1.3 of the document should be used for all measures from 1 January 2020. This document provides further clarifications and updates from Version 1.2 (draft for comment) published in October 2019. Details of changes can be found in the summary of updates to the guidance document which can be found below.