Insights
Market wide half hourly settlement, known as MHHS, is the biggest change to the electricity retail market in a generation. It moves every customer to settlement based on when they actually use electricity, half hour by half hour, rather than on broad profiles. For suppliers this is not a back office tweak. It touches data, systems, operating models and commercial strategy at once. This guide explains what MHHS is, why it matters, and how to get ready without disrupting billing.
By Christopher Fagan
Today most domestic and small business customers are settled using estimated consumption profiles. MHHS replaces those profiles with actual half hourly data for the whole market. The result is settlement that reflects real usage patterns, which rewards suppliers who can help customers shift demand and exposes those who cannot. It is the settlement foundation that makes time of use tariffs, smart charging and flexibility genuinely viable at scale.
Once settlement is based on real half hourly data, the accuracy of your demand forecasting and your data operations feeds straight through to your imbalance costs. Suppliers with clean data and good forecasting will settle more accurately and protect margin. Suppliers with weak data will feel it in their settlement position. MHHS also opens the door to sharper tariffs, but only for those whose systems can actually handle half hourly data end to end.
MHHS is being delivered as a coordinated industry programme overseen by Ofgem and Elexon, with a defined go live followed by a phased migration of existing meter points across the market. The timeline has been revised more than once, so the important discipline is to track the current published milestones rather than assume the dates from a year ago still hold. What does not change is the direction of travel and the fact that every supplier has to migrate.
Treat MHHS as a data and operating model programme, not a systems upgrade. Start by profiling your half hourly data quality honestly, because that is where the risk and the cost sit. Plan the migration in stages with clear fallback, and use the move as a chance to fix long standing data problems rather than carry them into the new world.
PEF combines settlement expertise with real delivery experience in energy retail, including on market wide change programmes. If you want a clear eyed view of your MHHS readiness, our energy and utilities and delivery excellence teams can help. Contact us to talk it through.
MHHS moves every electricity customer to settlement based on when they actually use power, half hour by half hour, instead of on broad estimated profiles. It is the settlement foundation that makes time of use tariffs and flexibility viable at scale.
It is a coordinated industry programme overseen by Ofgem and Elexon, with a defined go live followed by a phased migration of meter points. The timeline has been revised more than once, so the sensible discipline is to track the current published milestones rather than rely on older dates.
The priorities are data readiness, systems that can handle half hourly volumes, updated agent and service arrangements, an operating model and team that can run the new world, and a rehearsed migration that protects billing accuracy throughout.
If any of this is live for you right now, the senior people who wrote it are the people you would work with.