When will Market Wide Half Hourly Programme (MHHS) begin?

This programme is being led by Ofgem and as a supplier we are expected the programme to be fully implemented between May 2026 and May 2027.

Below is an overview of the timelines:

Preparation;  Now to May 2026 – this is when we are working on our systems, processes and making ensure our team will be ready for the change

Migration; August 2026 to May 2027

Migration to the MHHS model between Summer 2026 and May 2027

Conclusion of the MHHS programme – July 2027

Ofgem’s target for moving to the new four-month settlement timetable