Previously, we wrote a blog explaining what Market-wide Half-Hourly Settlement (MHHS) is and why it matters for your business. Now, it’s time to move from the “what” to the “when.” This article breaks down the official MHHS implementation timeline into clear, actionable stages so your business can plan ahead and meet the key deadlines.
Market-wide Half-Hourly Settlement (MHHS) is no longer a distant concept – it’s a major reform reshaping how UK businesses’ energy usage is measured and billed. In December 2024, Ofgem approved a six-and-a-half-month delay to key MHHS milestones to allow thorough testing. As a result:
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Migration starts in late October 2025
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Migration completes in May 2027
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The new (faster) settlement timetable goes live in July 2027
The countdown is on. Below we break down the critical dates – and what your business needs to do at each step.
What This Means for Your Business
1. The Metering Imperative: Every site must have a SMETS2 smart meter or an advanced AMR meter. Without one, your site cannot be migrated to MHHS, making this the most critical action for businesses.
2. Track Your Milestones:
- Oct 2025: Migration starts – ensure your sites are eligible.
- Oct 2026: Supplier Qualification deadline – ensure your supplier is MHHS-compliant.
- May 2027: Final migration deadline – all sites must be fully migrated.
3. Changes to Industry Roles: Familiar terms like “Meter Operator” (MOP) and “Data Collector” (DC) are being replaced with “Metering Service” and “Data Service”. These new terms will appear in contracts and communications moving forward.
4. A Live, Evolving Programme: The MHHS Programme Plan is regularly updated, most recently in August 2025. Staying informed of the latest updates is essential to avoid disruption and ensure smooth compliance.
Immediate Actions for Businesses
The first step is to audit your metering setup and upgrade any non-smart or non-AMR meters immediately, as these are essential for MHHS compliance.
But here’s the catch: chasing individual suppliers for MHHS qualification updates or migration schedules can be time-consuming and unclear. That’s where we come in.
At Black Sheep Utilities, we take that burden off your desk. Our team works directly with suppliers on your behalf, confirming their MHHS readiness and mapping out your transition plan — so you don’t have to.
We’ll keep you informed with the latest MHHS and Elexon updates, plus our own practical guidance, ensuring you never miss critical milestones. Most importantly, we provide expert oversight — simplifying compliance, minimising risk, and saving valuable time.
MHHS is a fundamental shift in the UK energy landscape. Businesses that prepare early – by checking meters, ensuring supplier compliance, and staying ahead of the timetable – will avoid last-minute disruptions and maintain smooth operations.
Black Sheep Utilities is already helping businesses do exactly that. We’ll make sure your sites are ready, your supplier is compliant, and your energy settlement stays seamless.
The time to act is now — and we’re here to guide you every step of the way.
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What is MHHS and why does it matter for my business?
MHHS (Market-wide Half-Hourly Settlement) is a UK-wide energy reform moving most sites to half-hourly settlement using smart or advanced meter data. For businesses, this means more accurate billing, faster reconciliations, and better energy insight. But it also requires compliant meters and an MHHS-ready supplier — without these, billing and site onboarding could be disrupted.
Do all my meters need to be upgraded for MHHS?
Yes. Any site with a non-smart or non-AMR meter must upgrade before migration. SMETS2 smart meters and advanced meters are MHHS-compatible.
The migration window opens in late October 2025. If meters aren’t upgraded by then, sites can’t be transitioned, putting compliance and billing at risk.
Which MHHS milestones should my business pay most attention to?
Key dates for businesses are:
Late Sept 2025 – Central MHHS systems go live
Late Oct 2025 – Migration window opens
May 2027 – Final migration deadline
July 2027 – Faster settlement timetable begins
Other programme milestones mainly affect suppliers, but their progress impacts your sites.
How do I know if my supplier is MHHS-ready?
Instead of chasing suppliers yourself, Black Sheep Utilities does this for you. We confirm their MHHS status and create a transition plan, so you know exactly where you stand.
What should I do now to prepare for MHHS?
Audit your meters – ensure all sites have smart or advanced meters.
Get supplier assurance – through us, not by navigating it alone.
Stay informed – follow MHHS updates from Black Sheep Utilities.
Get expert guidance – we’ll assess your position, manage suppliers, and build your readiness plan. The deadlines are fixed. Acting early avoids last-minute issues and keeps operations running smoothly.
Black Sheep Utilities is here to guide your business through MHHS, step by step.
