Introducing the Electricity Enquiry Service (EES) API Sandbox: Preparing for Market-wide Half Hourly Settlement (MHHS)

The Electricity Enquiry Service (EES) is undergoing important changes as part of the implementation of Market-wide Half Hourly Settlement (MHHS), and these changes will affect all EES users. To help organisations prepare for these updates, a dedicated MHHS EES API Sandbox has been created. This sandbox environment is now available to all users, with access keys being distributed to those who are currently signed up for the environment.

What is the MHHS EES API Sandbox?

The purpose of the MHHS EES API Sandbox is to provide a safe and controlled space for EES users to test and prepare their integrating systems in advance of the full implementation of MHHS. In this environment, users can simulate and explore the EES API responses they can expect under the new MHHS arrangements. The Sandbox will allow users to see how their systems interact with the EES API, helping to identify any potential issues before the changes go live.

Key features of the MHHS EES API Sandbox

  • Testing Environment: The sandbox provides a platform for users to prepare their systems for integration with the EES API under the new MHHS rules.
  • MHHS Migrated MPANs: A limited number of “dummy” MHHS Migrated  Meter Point Administration Numbers (MPANs) are available for all parties to use in testing scenarios.
  • Availability: The MHHS EES API Sandbox will remain accessible until MHHS Milestone M10 (currently scheduled for 24 September 2025), after which it will be replaced by an updated User Integration Testing (UIT) environment.

Accessing the MHHS EES API Sandbox

To gain access to the MHHS EES API Sandbox, existing EES users must contact the EES Service Provider C&C group via email at: helpdesk@groups.candc-uk.com. When requesting access, please provide the following information:

  • Organisation name
  • Role
  • MPID (if applicable)
  • Contact email address

 

For Third Parties who are currently accessing the EES API through an approved EES user, access to the sandbox would need to be requested through the approved EES User.

For MHHS SIT Parties

If you are part of the MHHS System Integration Testing (SIT) and need access to the integrated SIT version of the API, please contact the MHHS Test Team directly at: testing@mhhsprogramme.co.uk.

Final notes

This sandbox environment is a crucial step in preparing for the full implementation of MHHS and ensuring a smooth transition for all EES users. By testing in advance, organisations can identify potential issues early, improve system integration, and ensure compliance with the new MHHS rules.

We encourage all relevant parties to take advantage of the MHHS EES API Sandbox to ensure a seamless transition as we move toward a market-wide half hourly settlement.

For further information or assistance, please reach out to the appropriate contact emails provided above.

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