What is ECOES?

ECOES is a market information system supporting the electricity customer transfer process in Great Britain.

Rules and procedures relating to ECOES can be found in the MRA Agreed Procedure 15.

Who Can Access ECOES?

  • A Supplier or Distribution Business who has commenced Market Scenario Testing;
  • Price Comparison Websites; and
  • Any other party,  which can demonstrate a benefit to the domestic or non-domestic electricity market from being granted access.

How to Apply for ECOES Access

Suppliers or Distribution Businesses will be provided with access to ECOES during Market Scenario Testing. Appropriate documentation will be sent during this process.

Any other party, except Price Comparison Websites, must complete the ECOES application process shown below.

To apply for ECOES access, please download, complete and return to the following documentation:

Please contact the CAS Helpdesk by email at or call 0207 090 1024.

Price Comparison Websites are also required to complete a Access Agreement, as below:

PCW-TPI ECOES API Access Agreement-1.2

Please contact the CAS helpdesk as above, for further details.


The ECOES Privacy Policy and Terms of Use can be accessed below, to enable users to understand their obligations when using ECOES. Please note going forward the ECOES system will only include security updates, all other changes will only be made on the ECOES system.

User Guides

The specific company group user guides can be accessed below, to enable users to understand the functionality they have available to them. The user guides are in Microsoft Word format which gives users the ability to tweak them accordingly.


The ECOES Application Programming Interface (API) is now available for MRA Parties to sign up to. The latest version of the Technical Specification is below:

ECOES API Technical Specification v1.9



The ECOES User Requirement Specification contains guidance for ECOES Users and the latest version is available below:

ECOES User Requirements Specification v2.2