Energy Suppliers

MHHS is Coming: What Energy Suppliers Need to Know About How It’s Reshaping the Industry

5 min read

12 May, 2025

7:44

The UK’s energy landscape is on the brink of its most significant operational shift in decades. The Market-wide Half Hourly Settlement (MHHS) programme, mandated by Ofgem, is much more than a technology upgrade, but the foundation for a smarter, more flexible, and more sustainable energy system.

And it’s coming fast.

As timelines tighten and regulatory requirements roll out, energy suppliers, brokers, and technology partners alike need to prepare for one of the most complex migrations the industry has faced: moving nearly 30 million electricity meters (including 2.6 million business meters) to a new half-hourly settlement model.

But MHHS isn’t just about compliance. It’s about opportunity. It puts data in the hands of consumers, unlocks smarter pricing models, and positions the industry to meet net-zero targets with greater accuracy and stability.

Let’s break down what MHHS really means, why it matters, and how your business can stay ahead of the curve.

What Is MHHS?

Market-wide Half Hourly Settlement (MHHS) is a new electricity market arrangement that will use half-hourly consumption data to settle energy usage. This more frequent and accurate data enables real-time pricing, supports grid flexibility, and helps both suppliers and customers use energy more efficiently.

The goal is simple: a cost-effective, decarbonized electricity system that puts control back in the hands of consumers.

The MHHS programme was born out of the Electricity Settlement Reform Significant Code Review (SCR), and its implementation is being managed by the industry in alignment with Ofgem’s regulatory framework. The migration process will happen in phases, and suppliers must complete a qualification process that determines when their customers' MPANs will be migrated.

Power Back in the Hands of Energy Consumers

At the heart of MHHS is a shift in who holds the power—literally and figuratively.

This new framework gives consumers more visibility into, and control over, their energy usage. Enabled by next-gen smart meters and supported by dynamic pricing and time-of-use tariffs, customers can now make decisions based on real-time insights. Want to run the dishwasher when rates are lowest? Now you can.

For suppliers and brokers, this introduces a golden opportunity: to offer more personalized, behavior-driven plans and support tools that reflect individual consumption patterns.

At a macro level, this shift can support grid stability by spreading energy demand more evenly throughout the day. At the individual level, it means lower bills and a greater sense of agency for consumers.

But getting there won’t be easy.

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A Nationwide Migration Challenge

Here’s the scale of the task ahead: Over 30 million meters must move to the MHHS model, with nearly half of all meters still lacking compatibility. Smart meters have made progress across the UK, but they’ve hit resistance. As of the latest data, only 57% of all meters are smart or advanced. That leaves 43% that still need to be replaced or upgraded.

Why the resistance? For many consumers, the transition hasn’t been communicated clearly or convincingly. For suppliers, installation costs and coordination across legacy systems have created friction.

But with the MHHS deadlines now approaching rapidly, there’s no room for delay. The industry must redouble its efforts to educate, engage, and guide customers through this necessary shift.

Key Dates to Watch in MHHS Milestones

To manage this transition, Ofgem has laid out a detailed timeline of critical milestones. Here’s what to keep in mind:

October 2024: Suppliers must offer a solution that provides Electricity Half Hourly and Gas Hourly data access to all customers in Profile Class 1–4 or using less than 732MwH per year.
February 2025: An industry tool must be implemented to automatically change measurement classes for non-half-hour (NHH) meters, making them HH-ready.
March 2025: Major changes to top-line meter data begin. This includes:
- Replacing Meter Time Switch Code (MTC) with a Settlement Configuration (SSC) ID
- Splitting Line Loss Factor (LLF) into a Distribution Use of System (DUoS) Tariff ID and a new LLF
- Impacting customer bills, internal systems, and every data point that touches these identifiers
September 2025: Suppliers must be ready to update top-line supply numbers and begin migrating meters to HH settlement. No physical meter changes are required yet, but bills will look different.
March 2026: For any meters that still can’t be switched to HH, suppliers must begin physical upgrades or replacements.
May 2027: All eligible meters must be fully switched.
July 2027: The transition is complete. Profile Classes 01–04 will no longer exist, and all meters will be settled on a half-hourly basis.

Why MHHS Matters

The benefits of MHHS go far beyond compliance.

1. Better Pricing Through Better Data

With half-hourly data, suppliers can price energy more accurately, reflecting real-time market conditions instead of estimated usage. This allows for fairer, more transparent billing and supports more innovative pricing models like demand-based or time-of-use tariffs.

2. Energy Grid Stability

Granular usage data makes it easier to forecast demand, reduce peaks, and stabilize the grid. This becomes especially important as the UK integrates more renewable sources, which are inherently variable.

3. Reduced Margin Risk for Energy Suppliers

By reducing reliance on estimates and improving usage accuracy, suppliers can protect their margins, especially on contracts that previously suffered from inflated or incorrect usage assumptions.

4. New Frontiers for AI and Automation

With more accurate data, AI models can forecast demand, predict churn, personalize offers, and optimize contract terms. This opens new doors for brokers and suppliers to stand out in an increasingly competitive market.

Shaping the Future of the Energy Industry

As we move into 2025 and beyond, the shift to MHHS will continue accelerating. This is more than an operational adjustment—it’s a cultural shift for the entire energy industry.

From new billing structures to updated customer education materials, suppliers must be ready to support consumers through this change. At the same time, TPIs and brokers need systems that can accommodate evolving meter classifications and streamline onboarding, pricing, and contract management in real time.

Yes, there will be growing pains. The terminology will change. So will customer expectations. But the long-term outcome is clear: a smarter, cleaner, more responsive energy system that benefits everyone involved.