What is MHHS? Market wide Half Hourly Settlement explained
MHHS is the biggest change to electricity settlement in a generation. It moves the whole market from estimated profiles to actual half hourly data for every meter. Here is what it means, why it is happening and what suppliers need to be ready for.
What MHHS actually is
Market wide Half Hourly Settlement, or MHHS, is an industry programme to settle every electricity meter on actual half hourly consumption rather than estimated profiles. Today most domestic and smaller business supplies are settled using profiles, which are educated guesses about when energy is used. MHHS replaces those guesses with real smart meter data, so suppliers are settled on what customers genuinely used in each half hour.
It applies across the market, to domestic and non domestic customers alike, and it depends on smart meter data to work. That is why the smart meter rollout and MHHS are so closely linked: the settlement reform only delivers its full value once meters can report half hourly readings at scale.
Why it is happening
The prize is a market that prices energy closer to what it actually costs to serve at any given moment. When settlement reflects real half hourly usage, suppliers can offer time of use tariffs that reward customers for shifting demand away from peak times, which in turn supports batteries, electric vehicles and vehicle to grid. Ofgem has estimated net benefits to consumers in the region of 1.6 to 4.5 billion pounds through to 2045, alongside a system that is better able to absorb renewable generation on the path to net zero.
Timelines for MHHS have moved before. Migration is underway and running into 2027, with market wide go live scheduled for May 2027. Always check the current programme position from Elexon or Ofgem.
What it means for energy suppliers
Far more data
Every supply moves from a handful of periodic figures to forty eight settlement points a day, a step change in data volume.
New data flows
MHHS introduces new messages and processes. Suppliers must send, receive and reconcile them accurately and on time.
Exceptions to manage
Missing or bad readings create exceptions that must be resolved quickly, or settlement and billing suffer.
Migration effort
Moving existing supplies onto the new arrangements is a large, time boxed programme, not a flick of a switch.
Billing accuracy
Half hourly data done right means fewer estimated bills and disputes, done wrong it means more.
New tariff options
Real half hourly data lets suppliers design time of use products they simply could not offer under profiles.
Common questions
What does MHHS stand for?
Market wide Half Hourly Settlement. It settles every electricity meter on actual half hourly consumption instead of estimated profiles.
When does MHHS go live?
Migration is underway and running into 2027, with market wide go live scheduled for May 2027. Dates have shifted before, so check the current position from Elexon or Ofgem.
Does MHHS affect business customers?
Yes. It applies to non domestic as well as domestic supplies, and it opens the door to time of use tariffs that can reward businesses for shifting usage off peak.
How can OptiFlow help suppliers with MHHS?
We automate the new half hourly data flows and exceptions, so the extra volume and complexity does not overwhelm your operations team.
More on energy supplier automation
Getting ready for MHHS?
Talk to us about automating the new half hourly data flows and exceptions before go live.