The End of Estimates and Preparing Businesses for MHHS in 2026
Leveraging the mandatory settlement transition for strategic energy efficiency
As we navigate the crucial 2026 delivery window for the Market-wide Half-Hourly Settlement (MHHS) Programme, UK energy markets are undergoing a structural shift since privatisation. Overseen by Ofgem and managed centrally by Elexon, this transition moves the entire electricity system away from estimated usage profiles toward actual half-hourly consumption data. For UK companies, the 2026 supplier migration waves represent a simple back-office billing update and mark an distinct change in how corporate energy data is captured, analysed, and monetised. With Milestone 14 (M14) quickly approaching this October 28, 2026, organisations need to act soon to ensure their metering infrastructure and data strategies are prepared to capitalise on this increased visibility.
Milestone 14 (M14):
The milestone when all suppliers must be fully qualified to accept MPANs under the new MHHS target operating model.
Key Takeaways
- Mandatory Transition: All non-half-hourly (NHH) meters are actively being migrated to half-hourly (HH) settlement, with market-wide completion targeted for May 2027.
- Financial Accuracy: Settlement windows are shrinking from 14 months to just 4 months, drastically reducing estimated billing and aligning costs with actual operational behaviour.
- Data-Driven Governance: Granular data provides an audit-grade foundation for mandatory environmental reporting, supporting strict corporate governance and verifiable net-zero claims.
- Strategic Optimisation: Enhanced visibility allows advanced time-of-use tariff optimisation, direct load shifting, and the identification of previously hidden energy waste.
The End of Estimated Profiling
Historically, the UK electricity grid relied heavily on generic Profile Classes for sites lacking half-hourly metering. This meant businesses were billed based on an estimated “shape” of consumption derived from a small sample of similar users, rather than their actual real-time demand. This outdated system obscured operational inefficiencies and socialised the costs of grid balancing across all consumers.
The MHHS rollout actively dismantles this legacy framework. Using new centralised systems implemented by Elexon, the market is migrating toward a highly granular, event-driven data architecture. For corporate energy consumers, this means every 30-minute block of electricity usage will be recorded, validated, and financially settled based on empirical reality. While this places new demands on data collection and meter readiness, the upside for proactive organisations exists. It eliminates the financial ambiguity of estimated billing reconciliations and exposes the true cost of energy consumed during peak demand periods.
MHHS will effectively accelerate the shift toward half-hourly data as the baseline standard across the UK. For our customers, upgrading to HH data means improved completeness and detailed consumption metrics, leading to more consistent and accurate billing. Beyond just administration, it gives us a much greater ability to identify optimisation opportunities through detailed load profiling, directly supporting both cost savings and long-term carbon reduction.
Transforming Corporate Governance and Reporting
The implications of MHHS extend beyond the procurement team to affect corporate governance, financial forecasting, and operational cost control. Regulatory frameworks are demanding increasingly exact and verifiable data to substantiate corporate ESG targets. While estimated Scope 2 data is technically allowed under SECR’s comply or explain provisions, the gap between what regulators will accept and what investors, auditors and procurement partners will find credible is narrowing.
The transition to half-hourly settlement shifts the focus from theoretical carbon tracking to tangible financial savings. By gaining access to a stream of accurate, timestamped consumption data, organisations unlock the ability to engage meaningfully in Demand Side Response (DSR). Businesses can use this granular data to save costs as energy managers identify specific non-essential loads that can shift away from peak time pricing periods, directly lowering opex without disrupting core business output.
Additionally, as the settlement timetable shortens from a bloated 14-month window down to four months by mid-2027, the swiftness and accuracy of financial forecasting will further improve. Boards will have faster, more reliable insights into operational expenditures, eliminating the risk of reconciliation shocks and demonstrating the direct ROI of their DSR and energy efficiency initiatives.
Redefining Energy Management Capabilities
To harness the benefits of MHHS, the corporate approach to energy management needs to move with the transition. The sheer volume of data generated by a fully half-hourly metered portfolio necessitates a shift away from manual, retrospective invoice validation toward automated, predictive analytics. Managing this transition means you need to have the right data architecture and capable metering agents to handle the increased data flow.
For organisations with mixed portfolios of previously NHH and HH sites, this transition unifies their data landscape, providing a cohesive view of their whole operational footprint. The ability to monitor performance across all sites with precision is a step change for portfolio optimisation strategies.
This regulatory shift directly impacts our service delivery. For any client receiving Monitoring & Targeting (M&T), we can now apply it broadly across portfolios that historically contained a mix of HH and NHH sites. As discussed in our recent M&T session, the future Energise service is actively moving toward an HH data-led model rather than traditional invoice-led analysis. MHHS reinforces this direction, making robust, automated data collection an absolute for ongoing energy management and compliance.
Actionable Steps for 2026 Readiness
The implementation of MHHS is centrally coordinated through supplier migration waves that will run continuously through 2026. While the heavy lifting of the transition is managed by energy suppliers and data agents, it’s not advisable for the corporate consumer to be passive.
Directors should mandate a comprehensive audit of their current metering infrastructure, like making sure their existing metering estate is capable of half-hourly remote data collection. Discussing with suppliers to understand specific migration timelines will prevent operational blockages and the financial implications tied to it. More importantly, businesses need to ensure they have the internal processes or external partnerships in place to absorb and act upon the incoming wave of granular data.
Readiness and Optimisation
The transition to MHHS is a definitive moment for UK corporate energy strategy. It marks the end of estimated consumption and introduces exceptional data clarity. By preparing infrastructure and adapting analytical approaches now, businesses can turn a mandatory regulatory shift into a great driver for operational efficiency and verifiable decarbonisation.
The key for us is helping customers understand the immense value at stake, as access to HH data provides visibility into hidden inefficiencies. We strongly encourage businesses to sooner clarify their MHHS migration wave and timeline and assess their current metering capability and data readiness. Use this mandatory transition to support wider objectives, like cost reduction, carbon targets, and operational performance. Ultimately, this is a natural entry point into a broader M&T conversation, as the sheer value of improved data visibility quickly becomes unquestionable.
About the author
Joe is Managing Consultant and leads the Energy pod, advising customers on how they can become more energy efficient and reach their sustainability goals.
