MHHS

MHHS and the UK Grid: Why Half-Hourly Settlement Is a Market Architecture Shift

Inkwelldata

12 Feb 2026 • 4 min read

We are now less than eight months from October 2026, when the majority of meters will have migrated to Market-wide Half-Hourly Settlement (MHHS).

MHHS is often described as a billing reform. In practice, it represents a structural shift in how the UK electricity market allocates cost, risk and flexibility value.

        This is not primarily about increasing data volumes. It is about changing how economic accountability is determined.
    

From Statistical Smoothing to Interval Accountability

Under the legacy settlement model, most domestic and small commercial demand was allocated using standard load profiles. These profiles were statistical approximations of "typical" consumption behaviour. Portfolio volatility, communication gaps and timing inconsistencies were absorbed within aggregate assumptions.

Settlement occurred retrospectively and was reconciled over time.

MHHS replaces this model with explicit half-hourly interval allocation. Each migrated meter produces 48 settlement data points per day. Initial settlement occurs on a D+1 basis, with subsequent reconciliation runs refining allocation accuracy.

The material change is the reduction of abstraction.

Under interval-based settlement

Cost is determined by time-specific consumption.

Portfolio imbalance exposure reflects measured interval performance.

Flexibility value can be calculated against defined half-hour baselines.

Accountability becomes time-bound rather than statistically inferred.

Risk Redistribution, Not Digital Modernisation

MHHS should thus be understood as a redistribution of risk.

Under profiling, operational imperfections — communication failures, timestamp drift and firmware inconsistencies — were often diluted within statistical curves.

Under half-hourly allocation

Missing reads surface directly in imbalance positions.

Timestamp misalignment affects settlement intervals.

Communication latency influences settlement completeness.

Cohort-level device anomalies become economically visible.

Granularity narrows tolerance.

Risk that was previously averaged across portfolios becomes explicit at interval level. This sharper alignment of cost and behaviour is deliberate. It strengthens price signals and exposes volatility that was previously masked.

The DCC Backbone and Its Architectural Role

The Data Communications Company (DCC) remains the regulated communications backbone of the smart metering system. Its role is secure transport, identity assurance and authorised message delivery under the Smart Energy Code.

The DCC ensures that data moves reliably between authorised participants.

It does not however determine whether delivered data is temporally aligned, behaviourally coherent or optimally structured for settlement and flexibility coordination. Those responsibilities sit at a different architectural layer.

        Transport and economic allocation are distinct functions within the overall system.
    

The Emerging Coordination Layer — The Digital Spine

Between the device estate, the DCC communications backbone, supplier settlement systems, distribution-level operations, and system balancing processes, a coordination layer becomes structurally significant.

This coordination layer — the Digital Spine — must

Aggregate high-volume half-hourly telemetry across heterogeneous estates.

Validate temporal sequencing and behavioural coherence at interval level.

Detect cohort-level anomalies before they propagate into reconciliation cycles.

Provide deterministic, auditable baselines for flexibility participation.

Maintain consistent data models across retail, distribution and system interfaces.

        The Digital Spine ensures that interval transparency becomes economically and operationally coherent.
    

Altior is designed to operate within this role.

Architecturally, Altior can

Interface securely with the DCC backbone for data ingress.

Perform protocol-native aggregation across multi-vendor device estates.

Apply deterministic validation logic to interval telemetry.

Align timestamps and sequencing across distributed assets.

Cluster anomalies at cohort scale rather than device-by-device.

Route validated data to settlement engines, DSO interfaces and flexibility platforms in a controlled and traceable manner.

This preserves the integrity of national transport and settlement systems while strengthening coordination at participant level.

The objective is coherence across economic and physical layers.

Settlement Reform and Distribution Reform Are Converging

MHHS sharpens retail price signals.

At the same time, the distribution system is becoming more active. Distribution System Operators (DSOs) are increasingly required to manage EV charging clusters at feeder level, electrified heating ramp patterns, embedded generation variability, and local flexibility participation.

Interval settlement makes domestic consumption behaviour economically explicit. Demand that was previously smoothed within profiles is now visible at half-hour resolution, exposing clustering effects from EV charging, electrified heating and distributed generation.

Concurrently, distribution reform — as networks transition from passive Distribution Network Operator (DNO) models to more active DSO coordination — makes local feeder constraints increasingly visible and actively managed. Thermal limits, voltage stability and reverse power flows are no longer addressed solely through reinforcement; they are increasingly managed through forecasting, flexibility procurement and constraint optimisation.

These developments are converging.

        Half-hourly transparency provides the measurement foundation. Measurement alone, however, does not ensure stability. Coordinated validation and aggregation across the domestic–distribution boundary are required to ensure that interval-level economic signals align with physical network constraints, preventing transparency from amplifying volatility at feeder level.
    

Community Assets and Economic Legibility

As electrification accelerates, value and variability increasingly originate at community scale: shared batteries, aggregated EV fleets, rooftop solar clusters, and domestic flexibility portfolios.

Under profile-based settlement, these patterns were largely invisible.

Under MHHS, they become interval-legible.

        Community assets are a structural outcome of electrification combined with time-based markets.
    

The question is not whether they participate. It is whether their participation is coherently coordinated across settlement, distribution and system layers.

October 2026 as a Visibility Threshold

October 2026 is not merely a programme milestone.

It represents a structural transparency event.

Portfolio behaviour becomes interval-explicit. Risk shifts from statistical modelling to measured allocation. Flexibility value becomes provable against half-hour baselines.

MHHS increases precision.

        Architecture determines whether that precision strengthens the grid — or merely exposes its seams.
    

In Part 2, we examine how interval transparency interacts with physical network constraints, and why federated coordination — rather than centralised reconciliation alone — becomes essential as granularity increases.