The UK electricity market is undergoing one of its biggest reforms in decades. Market-wide Half-Hourly Settlement (MHHS) will modernise how electricity consumption is measured, reconciled, and billed. For businesses, the shift represents both a challenge and an opportunity, as smarter data and new market structures pave the way for greater efficiency and flexibility.

What is MHHS?

MHHS means that all electricity usage across Great Britain, whether residential, commercial, or industrial, will be settled using half-hourly (HH) data. Today, only the largest businesses are required to settle this way. Under MHHS, all supply points (MPANs) will transition to HH settlement, providing the market with a far more accurate view of demand.

Why is it Being Introduced?

The current system relies heavily on Non-Half-Hourly (NHH) data, which groups consumers into broad profiles. These no longer reflect modern usage patterns in an era of smart meters, electric vehicles, storage, and flexible consumption. MHHS will use actual HH data from smart and advanced meters to settle accounts, making the process more precise.

Ofgem estimates that MHHS will deliver £1.5 to £4.5 billion in net benefits to consumers by 2045, largely through efficiency gains, better forecasting, and increased market competition.

The Benefits

• Smarter insights: HH data gives a detailed view of when energy is consumed, improving forecasting and enabling better demand planning.

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• Flexibility for Net Zero: With accurate data, suppliers can offer more flexible tariffs that reward customers who shift demand to off-peak times. This reduces reliance on carbon-intensive generation.

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• Cost savings: Businesses engaging with smart tariffs and flexibility schemes may lower bills by adjusting consumption patterns.

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• Innovation: Access to high-quality consumption data opens the door for new products and services, from battery optimisation to advanced demand-side management.

Key Industry Changes

The transition to MHHS involves more than just new data flows. Several structural changes are being introduced across the market:

• All MPANs settled half-hourly. Settlement will move from profile-based assumptions to actual consumption data.
• Shorter settlement timescales. The process will move from around 14 months today to just 4 months by July 2027.
• New market segments. The market will be divided by meter type, including Smart, Advanced, and Unmetered, rather than by old measurement classes.
• Replacement of legacy agents. Existing Non-Half-Hourly agents will be replaced by new Data Services and Metering Services providers aligned to the new structure.

Timeline

The MHHS rollout will take place in stages between September 2025 and July 2027:

• September 2025: Industry-wide migration begins.
• May 2026 to May 2027: Business customers transition to HH settlement.
• July 2027: Programme completion. All MPANs settled half-hourly and new four-month settlement timetable adopted.

What This Means for Businesses

For many organisations, the impact will depend on the type of meters in place. Businesses with smart or advanced (AMR) meters will be better positioned to benefit. Those still using older Non-Half-Hourly meters will need to upgrade to participate fully in the new system.

Expected changes for businesses include:

• More accurate settlement across all supply points.

• Updates to billing, quotes, and contracts as HH settlement replaces NHH.

• New terminology and reclassification of MPANs.

• Greater access to flexible tariffs, demand response schemes, and smart technologies.

Preparing for the Transition

Most of the work is happening behind the scenes within suppliers, data services, and metering providers. However, businesses can prepare by:

• Checking meter capability. Ensure sites are equipped with smart or AMR meters to unlock HH data benefits.

• Reviewing energy strategy. Explore opportunities to use flexibility, smart tariffs, storage, and EV integration.

• Understanding the impact on billing. HH settlement may change how costs appear on invoices.

Looking Ahead

With the technical design now baselined and the build of central systems underway, MHHS is moving from planning into delivery. By moving to accurate, real-time consumption data, the programme will make settlement faster, fairer, and more reflective of actual usage. The industry’s focus is on testing, integration, and preparing market participants for the transition.

As the programme moves forward, one thing is clear: MHHS is a strategic enabler of the UK’s Net Zero journey.