# Market-wide Half Hourly Settlement (MHHS) explained - Link: https://imserv.com/blog/market-wide-half-hourly-settlement-mhhs-explained/ - Published: 2026-07-24T08:01:39+00:00 - Author: Claire Laveaux Market-wide Half Hourly Settlement (MHHS) is a UK electricity market reform led by Ofgem that requires energy consumption to be settled in 30-minute intervals using actual meter data, replacing the estimated or averaged usage profiles currently applied to many non-half-hourly meters. The programme aims to modernise billing accuracy, support net-zero goals, and enable smarter energy tariffs. Key milestones fall in October 2026 and May 2027, by which point all meter points must be migrated. IMSERV holds accreditation across all MHHS roles and segments. ## Market-wide Half Hourly Settlement (MHHS)⏎ explained. **By IMSERV Europe Ltd** Market-wide Half hourly (MHHS) is the UK’s biggest energy shift in decades. Led by energy regulator [Ofgem](https://www.ofgem.gov.uk/), the programme changes how energy usage is billed by requiring businesses to settle their energy consumption in 30-minute intervals rather than relying on estimates or daily averages. According to the MHHS Programme, it’s a smarter, fairer, and more environmentally friendly way to measure and manage electricity usage across the UK.  --- ## Why has MHHS been introduced? ### The main reasons for the change to half hourly settlement: Key reasons include:  1. Modernise the UK electrical systems and its processes   2. Encourage more flexible energy use  3. Support the transition towards a Net Zero future   4. Lower bills for energy consumers  --- ## What is Market-Wide Half Hourly Settlement? MHHS is a major reform of the electricity market that changes how electricity consumption is settled. Instead of relying on estimated usage profiles for many consumers, settlement will be based on actual half-hourly consumption data wherever possible. Many legacy non-half-hourly meters are settled using estimates of when customers are expected to use electricity. MHHS will move the electricity market away from this and towards using as much actual data as possible.   --- ## When does Market-Wide Half Hourly Settlement take effect? ### The MHHS programme is broken down into key milestones. **28^(th) October 2026: ** * Milestone 14 (M14), when all suppliers must be fully qualified.  **7^(th) May 2027:** 1. The initial MHHS migration programme is due to be completed by milestone 15 (M15) which is anticipated for 7th May 2027. 2. This means the programme intends to have all MPANs migrated into MHHS by this date. --- ## How will MHHS impact customers?  MHHS is primarily about improving the accuracy of electricity billing and enabling more flexibility based on when electricity is used, rather than just how much is used. MHHS is designed to make better use of meter data and support the transition to a smarter, lower-carbon energy system. --- ### Key benefits of moving from HH to MHHS include:   * Accurate bills  * Support for net-zero  * Greater energy usage visibility --- ## What services are IMSERV accredited for in Market-Wide Half Hourly Settlement?  ### IMSERV are accredited across all roles for all MHHS segments, including:  * [Advanced Data Service (ADS)](https://www.mhhsprogramme.co.uk/api/documentlibrary/Design%20Documents/MHHSP-METH002_ADS_Validation_Estimation%20v5.7%20Redlined%20version.pdf) * [Meter Service Advanced (MSA)](https://www.elexon.co.uk/documents/groups/dwg/2018-meetings-dwg/november/dwg13-01d-service-requirements/) * [Smart Data Service (SDS)](https://smartdatagroup.org/sds)   * [Metering Service Smart (MSS)](https://imserv.com/blog/a-guide-to-the-new-agent-roles-in-the-world-of-market-wide-half-hourly-settlement/) * [Meter Data Retriever (MDR)](https://www.assured.energy/news-and-insights/energy-usage/how-the-market-wide-half-hourly-settlement-mhhs-will-work/) * [Unmetered Data Service (UMSDS)](https://imserv.com/unmetered/) --- ## How will MHHS improve the accuracy of my energy bill?  Market-wide half hourly settlement (MHHS) uses more frequent meter readings, helping suppliers bill customers based on actual energy usage rather than estimates. This means bills should be more accurate and easier to understand.  --- ## How can MHHS help me benefit from smarter and potentially cheaper energy tariffs? MHHS supports smart tariffs that can offer lower prices at certain times of the day, giving customers more opportunities to save money by using energy when it is cheapest.  --- ## What new technologies and innovations will MHHS enable? MHHS supports technologies such as smart home devices, electric vehicles, battery storage and heat pumps, helping customers better manage their energy usage and costs. --- ## How will MHHS make the energy market more efficient and cost-effective? By using more accurate consumption data, MHHS helps suppliers and network operators make better decisions, reducing inefficiencies and supporting a more flexible and cost-effective energy system for everyone**.**  --- ## MHHS? Easy Peasy 🍋 ### Get MHHS-ready without the jargon headache with IMSERV. Our energy experts can help you make sense of the changes, understand what they mean for your business and get your next steps moving.   Speak to an IMSERV data expert today and make half-hourly settlement feel easy peasy. Drop us a line. We’re ready for you. [**Get In Touch**](https://imserv.com/contact-us/)