Market-Wide Half-Hourly Settlement: How a smarter energy system benefits businesses

Summary

Market-Wide Half-Hourly Settlement (MHHS) represents a major milestone in the development of a smarter, more responsive UK energy system. From October 2025, energy suppliers will begin migrating customer accounts so that all supply points are settled using half-hourly consumption data from smart and advanced meters, rather than relying on estimates or standard profiles. This reform, enabled by central systems going live in September 2025, will improve billing accuracy, enable time-of-use pricing, and create new opportunities for consumer-focused innovation.

What is MHHS – and why does it matter?

Market-Wide Half-Hourly Settlement (MHHS) will require electricity suppliers to use half-hourly electricity usage data recorded by smart and advanced meters to calculate how much energy each customer has consumed. This will replace the existing method, which relies on estimates or standard usage profiles based on customer type rather than real-time data. By moving to half-hourly settlement, MHHS will provide a more accurate picture of electricity use across the system.

When does MHHS come into effect?

The next phase of MHHS begins in September 2025, when central systems go live. Electricity suppliers will then begin migrating customer accounts to half-hourly settlement processes. This transition will take place over an 18-month period, with full market adoption expected by mid-2027.

How will MHHS benefit businesses?

MHHS supports the development of a more flexible, low-carbon energy system. For consumers, the benefits include:

• More accurate billing
• Greater transparency and control over energy use
• Access to time-of-use tariffs with the potential for financial savings
• New services designed around individual consumption patterns

These outcomes will help businesses engage more actively with their energy use and contribute to the UK’s wider decarbonisation efforts.

Will businesses need to take action?

For most businesses, the introduction of MHHS will happen automatically. No action will be required unless your energy supplier contacts you directly. If you already have a smart or advanced meter, your usage data will start being used differently for billing and settlement purposes as soon as MHHS is introduced.

Some consumers (particularly those on time-of-use or non-standard tariffs) may choose to engage more actively with how and when they use electricity. This could include reviewing energy habits or using tools that help track consumption.

How is SMS supporting MHHS?

SMS views MHHS as a key enabler of progress across the UK energy system. By working in close collaboration with suppliers, partners, and industry bodies, we are committed to supporting a successful rollout that delivers both technical advancement and lasting benefit for consumers.

Our role is grounded in our broader purpose: enabling smarter, more sustainable infrastructure that drives value, enhances reliability, and supports the UK’s long-term energy goals.