What’s the Market-wide Half Hourly Settlement (MHHS) and what does it mean for businesses?

What’s the Market-wide Half Hourly Settlement programme?

Led by Ofgem, MHHS is an industry-wide programme that’s set to modernise how electricity’s accounted for and billed in Great Britain.

At its core, it means that the settlement of electricity usage for domestic and non-domestic meters alike will use half hourly (HH) consumption data. This is a step-change from the current system, where most smaller sites are settled using estimates or profiles.

For many large organisations, HH settlement isn’t new - many already have half hourly meters and settlement arrangements in place. But, MHHS is about standardising this approach across the board to create a more efficient, transparent, and sustainable energy system that helps the UK meet its net zero targets.

Why is MHHS happening?

There are three key drivers behind MHHS:

1. Enable a smarter, more flexible energy system With increasing renewable generation and electrification, a flexible grid is vital. MHHS provides the data accuracy needed to support demand-side response and time-of-use pricing.

2. Promote fairness and cost-reflectivity Settlement for electricity customers will be based on their actual usage rather than estimates. Those who can shift or reduce demand at peak times may benefit financially.

3. Support net zero Accurate, granular data allows businesses to better track, manage, and reduce their carbon impact – particularly as they adopt electric vehicles (EVs), on-site generation, or battery storage.

Ofgem expects MHHS to bring £1.5bn to £4.5bn in net benefits for British consumers by 2045.

What does MHHS mean for organisations?

If you already operate on a half hourly basis, you might think MHHS won’t change much. However, there are several important elements you should consider:

• More accurate cost allocation across your portfolio: If your business has a mix of large and smaller sites, MHHS will bring consistency. From July 2027 – Ofgem’s target for MHHS completion – all sites will be settled on the same HH basis, giving you clearer visibility of costs and consumption patterns across your estate.
• Greater opportunities for flexibility: If you can flex your demand, by shifting non-critical processes or leveraging battery storage for example, you could reduce your costs. Over time, pricing is likely to become even more sophisticated.
• A need to optimise your demand profile: Energy use during peak periods will become more expensive. Understanding and managing your load profile will become even more important to helping you avoid higher charges.
• Increased value from smart technologies: MHHS strengthens the case for investment in smart energy solutions: automated demand control, smart building management, EV smart charging, and behind-the-meter storage all stand to deliver greater returns.

The MHHS timeline

MHHS is taking place in stages between September 2025 and July 2027:

• September 2025 – Industry systems go live
• October 2025 to May 2027 – Industry migration window
• May 2026 to May 2027 – Industry designated migration window for Drax Energy Solutions; we’ll commence our migration in August 2026
• July 2027 - Ofgem’s target for MHHS completion

What should you be doing now?

If you already have a half hourly meter, you don't need to do anything.

If you have non half hourly (NHH) meters, or no meter(s) at all, we’ll contact you in due course to advise you what to do next. This could include choosing to get a smart or advanced meter through our metering team: smart@drax.com.

Market-wide Half Hourly Settlement is more than just a regulatory update - it’s the foundation for a smarter, greener energy system. For organisations, it presents an opportunity to take greater control of energy costs and carbon impact through better data, smarter technology, and strategic flexibility.

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