MHHS Will Not Raise Your Energy Costs. It Will Reveal Them.
Market-Wide Half-Hourly Settlement (MHHS), is often described as a technical reform of the UK electricity market.
In practice, its impact is more fundamental.
MHHS changes how electricity consumption is measured, how it is settled and how costs are allocated across the system. For Commercial Real Estate portfolios, that has direct implications for cost control, billing accuracy and occupier recharging.
Across the portfolios Carbonxgen manages, MHHS is already shaping how we think about data infrastructure, recharge methodology and billing validation. The question for most portfolios is not whether it will affect them. It is whether they will be ready when it does.
What Is MHHS?
MHHS is a regulatory reform that will move all electricity meters in Great Britain to half-hourly settlement.
This means:
- Electricity consumption will be measured and settled in 30‑minute intervals, rather than using coarse or aggregated estimates.
- Profile‑based and estimated usage will be progressively replaced with data derived from half‑hourly readings (primarily from smart and advanced meters).
- Suppliers will be financially settled based on when electricity is actually used, rather than on assumed average consumption patterns
The transition will take place over the coming years, with implementation milestones already underway.
Why MHHS Matters for Cost
Under the current system, many non-half-hourly meters rely on estimated consumption profiles. These profiles assume how energy is used, smooth demand across time periods and do not reflect actual building behaviour.
This creates a disconnect between real consumption, settled (billed) consumption and the true cost drivers within the electricity system.
MHHS is designed to remove that disconnect. Once implemented, electricity settlement costs will align more closely with actual half‑hourly usage patterns, peak demand periods will become more visible and system inefficiencies will be easier to identify and quantify.
This introduces greater accuracy, but also greater exposure. Buildings that consume electricity inefficiently, or predominantly during periods of high system demand, may face higher costs. Conversely, buildings with well‑managed demand profiles — particularly those able to shift or reduce usage at peak times — may benefit from lower or more optimised costs.
The Emerging Cost Risks
MHHS does not automatically reduce cost. It increases transparency. That creates several potential risks.
1. Exposure to Peak Demand Pricing
Electricity costs vary depending on when energy is consumed. Under MHHS, peak-time usage becomes more visible, cost allocation becomes more time-sensitive and inefficient demand patterns become more expensive to maintain.
2. Increased Billing Complexity
With half-hourly data, billing structures become more granular and validation becomes more complex. Errors become harder to identify without structured processes in place. Without proper oversight, this increases the risk of incorrect or misunderstood charges passing through unchallenged.
3. Pressure on Recharge Accuracy
In multi-let buildings, occupier recharges must reflect actual consumption. Data accuracy becomes more visible to tenants and disputes are more likely to arise where methodology is unclear or inconsistent. MHHS raises the expectation of transparency and, with it, the consequences of falling short.
The Opportunity: Better Cost Control Through Data
While MHHS introduces complexity, it also creates a significant opportunity.
With accurate half-hourly data, portfolios can:
- Identify when energy is being used inefficiently
- Shift demand away from peak periods
- Improve building performance
- Align cost more closely with operational reality
This supports a more proactive approach to cost management, one where decisions are driven by what is actually happening in the building, not assumed patterns applied across the system.
Why Data Becomes the Critical Factor
MHHS is not simply a metering change. It is a data transformation.
To respond effectively, portfolios need reliable half-hourly data across all relevant meters, structured validation processes, clear visibility of consumption patterns, and integration between billing and recharge systems.
Without this foundation, the benefits of MHHS are difficult to realise and the risks are harder to manage. With it, portfolios gain a clearer and more actionable view of energy cost drivers.
This is where preparation matters. MHHS is often approached as a compliance exercise, and compliance is necessary. But the portfolios that will be best positioned are those that treat it as part of a wider cost and data strategy, reviewing metering infrastructure and readiness, aligning data collection with portfolio reporting, updating recharge methodologies to reflect increased granularity, and embedding half-hourly insight into operational decision-making.
The Wider Impact Across the Portfolio
When managed effectively, MHHS can connect directly to improved outcomes across several areas:
- Cost optimisation: clearer understanding of demand‑driven and time‑based cost exposure
- Data confidence: improved accuracy, consistency and auditability of consumption data
- Occupier relationships: more transparent, defensible and evidence‑based recharges
- Sustainability performance: enhanced visibility of energy usage patterns, supporting carbon reduction and flexibility initiatives
Taken together, these outcomes reinforce the broader shift towards data‑led portfolio management. They are realised by portfolios that treat MHHS as a strategic tool for insight and optimisation, rather than simply a regulatory requirement to be satisfied
How Carbonxgen Supports MHHS Readiness
Carbonxgen’s approach to MHHS extends beyond individual assets or regulatory compliance. We take responsibility for preparing commercial real estate portfolios for MHHS and integrating its impacts into wider energy and portfolio management strategies.
In practice, that means:
- Assessing metering infrastructure and MHHS readiness
- Ensuring accurate and consistent half-hourly data collection
- Validating billing against actual consumption patterns
- Aligning occupier recharge methodologies with increased data granularity
- Integrating MHHS into wider cost, compliance and sustainability frameworks
This ensures portfolios are not only compliant, but also positioned to use MHHS as a source of insight and control rather than simply a regulatory obligation.
Looking Ahead
MHHS represents a structural change in how electricity costs are calculated and allocated. For commercial real estate portfolios, its impact will be felt through more accurate billing, greater visibility of inefficiency and increased scrutiny around cost allocation and recharges.
The portfolios that respond most effectively will be those that treat MHHS as a data and cost management opportunity, not simply a regulatory milestone to be achieved. The groundwork for that shift starts now.
Talk to Carbonxgen
If you would like to understand how MHHS will affect your portfolio, or assess your readiness from a cost and data perspective, we would be pleased to support a structured review.
Talk to us about preparing for MHHS and strengthening control over your energy costs.