Energy suppliers

Energy suppliers have legal obligations under the Energy Company Obligation (ECO) scheme if they:

  • have more than 250,000 domestic customers
  • provide more than 400 gigawatt hours of electricity or more than 2,000 gigawatt hours of gas.

When do suppliers become obligated?

In December each year, we ask suppliers to tell us how many customers they have and how much energy they supply. If they reach the two eligibility thresholds above, the supplier becomes obligated under the following year of the scheme, which usually begins in April.

We offer advice and assistance to all newly obligated suppliers to make sure they’re prepared to take part in the scheme.

What are suppliers’ responsibilities?

Suppliers are responsible for meeting their obligations and ensuring that they, and any members of the supply chain acting on their behalf, comply with the scheme requirements.

How are suppliers’ targets worked out?

As scheme administrator, we’re responsible for setting suppliers’ obligations. We do this using a calculation based on their share of the gas and electricity supply market. This is determined by ECO legislation.

The ECO register

Each month, obligated energy suppliers notify us of the measures they’ve delivered by uploading them to the ECO register.

Where do I find out more?

You can find more detailed information in the Contacts, guidance and resources section of our website. This includes our official ECO2 guidance, as well as information on ECO2 Monitoring, the AWG Guidance note, ECO2 Appropriate Guarantees and key templates and checklists.

The ECO reporting working group section of our website also contains key standardised ECO templates such as the Declaration of Conformity and Completed Installation and AWG and Private Domestic Premises Checklist.

Publications and updates

  • Published: 14th Feb 2017
  • Open letters & correspondence
  • 1 Associated documents
This letter provides detail on Ofgem's approach to the closedown of the Carbon Saving Community Obligation (CSCO) aspect of the Energy Company Obligation (ECO) scheme.

  • Published: 15th Dec 2015
  • Guidance
  • 1 Associated documents
This document outlines our approach to dealing with poor performance for both technical and score monitoring of measures installed under ECO.

  • Published: 19th Nov 2015
  • Guidance
  • 5 Associated documents
Guidance for suppliers on technical and score monitoring for measures installed under ECO2.

  • Published: 19th Oct 2015
  • Guidance
  • 1 Associated documents
Ofgem's ECO Toolkit for installers and other third parties involved in delivering ECO measures. This suite of resources aims to improve understanding of how an ECO measure is processed.

  • Published: 1st Oct 2015
  • Guidance
  • 1 Associated documents
This page contains information about eligible measures under ECO2, as well as details about non-standard lifetimes.

  • Published: 19th Aug 2015
  • Factsheets
  • 1 Associated documents
This document explains how Ofgem will collect, use, and protect personal information that it obtains under the Energy Company Obligation (ECO) scheme.

  • Published: 23rd Jul 2015
  • Guidance
  • 1 Associated documents
This guidance note explains our approach to awarding a standard lifetime condition for wall insulation measures without an appropriate guarantee under ECO1.

  • Published: 22nd Jun 2015
  • Open letters & correspondence
  • 1 Associated documents
An update on key approaches and timelines for the closedown of ECO1. This includes some changes to previous guidance.

  • Published: 22nd Apr 2015
  • Open letters & correspondence
  • 4 Associated documents
These documents relate to the hard-to-treat cavity (HTTC) wall insulation measures installed before 1 January 2014.

  • Published: 1st Apr 2015
  • Open letters & correspondence
  • 1 Associated documents
This explains how we let energy suppliers know that we have received an application to extend the notification deadline for a completed measure under the Energy Company Obligation (ECO).

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