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Delivering outcomes to support a more cost-effective electricity industry

Climate change presents the world with a challenge to urgently protect our planet, our economy and our populations.

The UK has set a world-leading net zero target, the first major economy to do so. Having set the target, the focus turns to delivering against that target. In the Energy White Paper ‘Powering our Net Zero Future‘ the government has set out an ambitious programme to build a fairer greener energy system.

Market-wide Half-Hourly Settlement (MHHS) is a key enabler of the flexibility to support the transition to Net Zero. The MHHS Programme will contribute to a more cost-effective electricity system, encouraging more flexible use of energy and helping consumers lower their bills.

Introduction from the MHHS Programme SRO

The achievement of the following Programme milestones marks a significant step forward in how electricity is used and accounted for:

  • Milestone 10 (M10): Central systems ready to migrate Meter Point Administration Numbers (MPANs)
  • M11: Commencement of the 18-month migration period for Unmetered Supplies (UMS) and Advanced Metered MPANs
  • M12: Commencement of the 18-month migration period for Smart and Non-Smart Metered MPANs
  • M13: Load Shaping System (LSS) switched on 

Market-wide Half-Hourly Settlement (MHHS) reform will see the industry working together to deliver this ambitious and transformative Programme. The MHHS Programme is an industry first, in that Ofgem has placed responsibility on the industry to deliver the Programme and appointed Elexon as the Senior Responsible Owner (SRO).

M10 confirmed that central systems are ready to migrate MPANs, while M13 confirmed that the Load Shaping System was switched on. Building on these foundations, approval of M11 and M12 marked the formal start of the industry-wide migration phase. Participants have started migrating customers to the new MHHS arrangements, with activity coordinated through the Migration Control Centre (MCC) and monitored through Programme governance.

The first successful migration events have taken place, demonstrating that systems, processes and participants are ready to operate in the new environment. This represents a pivotal point in the Programme as we collectively drive towards full migration completion at M15 and transition to new settlements at M16.

These milestones demonstrate the strength of the governance and design approach we have put in place and provide a firm foundation for the next stages of delivery. The focus now turns to continued migration of MPANs , qualification of remaining industry participants and preparing for full implementation of the MHHS arrangements.

The outcome of MHHS will be a faster and more accurate settlement process for all market participants, introducing site-specific reconciliation using half-hourly data. This will be a key enabler of a smarter and more flexible energy system and will play a vital role in supporting the United Kingdom’s transition to Net Zero. Elexon, as an expert in balancing and settlement processes at the centre of the wholesale electricity market, is proud to lead the Programme and to support the industry in laying the foundation for the future.

Recognising industry concerns about potential conflicts of interest, a Separation Plan was established in the early stages of the Programme, to clearly detach Elexon’s role as a Programme participant, delivering the central systems, from its programme management role. The Elexon Board, Ofgem and an Independent Programme Assurance (IPA) function continue to oversee the separation arrangements to ensure transparency and accountability.

The MHHS Programme continues to set the blueprint for how the industry can work collectively to deliver complex change. We look forward to maintaining the collaborative and transparent approach that has brought us to this point, and continuing to work closely with industry to deliver the benefits of MHHS.

Helen Adey, MHHS Programme SRO

Introduction from Ofgem MHHS Programme Sponsor

Reaching Milestones 10 (M10), 11 (M11), 12 (M12) and 13 (M13) represents a significant step forward  for the Market-wide Half-Hourly Settlement (MHHS) Programme and for the wider energy industry. These achievements provide confidence that the governance and delivery model is working, and that industry remains on track to implement this vital reform. MHHS continues to be central to Ofgem’s strategic priority of enabling flexibility across the energy system in support of the United Kingdom’s transition to Net Zero.

Following approval of M11 and M12, the first meters have been successfully migrated, marking the beginning of the 18-month migration phase for Unmetered Supplies (UMS), Advanced, Smart and Non-Smart Metered Meter Point Administration Numbers (MPANs). This reflects a major achievement for the Programme and demonstrates that the market is ready and capable of operating within the new MHHS arrangements.

Since our 2021 decision to implement MHHS, Ofgem has retained overall accountability for programme outcomes, with Elexon appointed as the Senior Responsible Owner (SRO). In our Final Impact Assessment, we estimated that MHHS will deliver net benefits to consumers of between £1.5 billion and £4.5 billion by 2045. With M10–M13 achieved and migration now underway, the industry is now well positioned to realise those benefits.

MHHS is an essential reform of settlement arrangements and a cornerstone of creating a smarter and more flexible energy system. Ofgem remain committed to supporting the Programme so that the benefits of MHHS are delivered to consumers at the earliest practicable opportunity.

Melissa Giordano, Ofgem, Programme Sponsor