Market-wide Half-Hourly Settlement
(MHHS) Programme

 

Market-wide Half-Hourly Settlement (MHHS) Programme - October 2025 - May 2027

 

In 2017, the energy regulator Ofgem announced a review to evaluate whether the entire electricity market, encompassing both commercial and residential properties, should transition to half-hourly settlement. Market-Wide Half-Hourly Settlement (MHHS) represents a significant reform in the UK energy market. It utilises smart meters to record electricity usage in half-hourly intervals, enabling more accurate billing, improved demand forecasting, and the development of innovative products.

 

This initiative is vital for achieving the UK’s Net Zero targets, delivering both environmental benefits and potential cost savings for consumers and businesses. From October 2025, approved suppliers will begin transitioning their clients to the half-hourly settlement process, aiming to complete the transition by May 2027. These deadlines reflect the revised timeline announced by Ofgem following an extension.

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Market-wide Half-Hourly Settlement (MHHS) Programme:

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• Aims to facilitate the transition to Net Zero.

• Involves implementing half-hourly meter-specific settlement across the energy market.

• Will enable price-responsive, dynamic, and innovative tariff structures for both Domestic and Non-Domestic sectors.

• Energy suppliers will transition their customers’ meters to the new half-hourly settlement process in waves.

• The regulatory deadline for MHHS compliance is October 2026.

• By October 2026, all suppliers, including your organisation, must complete the transition to the new MHHS arrangement.

• Oversight for the programme is provided by Ofgem.

 

General Benefits and Updates:

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• MHHS will create opportunities for a smarter, more cost-effective, and flexible energy system.

• Customers will be better informed and empowered in managing their energy consumption

• It supports the integration of renewable energy sources.

• It promotes more flexible and efficient energy consumption.

• MHHS will provide customers with more accurate billing.

• It offers the potential for dynamic pricing models.

 

Meter Timeswitch Code (MTC):

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• The MTC (Meter Timeswitch Code) will be removed.

• Customers with smart/advanced communicating meters will be offered a simplified pricing structure.

• Standardised timing structures, such as 7 am to midnight for day rates and midnight to 7 am for night rates, will replace the current day/night timing combinations.

• The aim is to make energy pricing more straightforward and easier to manage for both businesses and customers.

 

Meter Migration to MHHS:

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• Migration to the new half-hourly settlement arrangements will occur in phases over approximately nine months.

• The migration plan will prioritise minimising disruption by avoiding migrations during customers’ contract renewal periods.

• The organisation is working closely with Metering Agents to ensure a smooth transition by the regulatory deadline.

 

Meter Compatibility:

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• All meters, including traditional ones, will be migrated to comply with the new half-hourly settlement arrangements.

• SMETS, SMETS2, RCAMR, and traditional meters will all eventually need to be compatible with MHHS regulatory requirements.

 

Pricing and TCR Bandings:

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• The TCR (Targeted Charging Review) level, which is part of the DuOS tariff ID, will continue to determine the standing charges customers pay.

• As profile classes are phased out and data from smart meters is used, pricing will be based on more accurate consumption data.

• Customers will gain more flexibility to select pricing plans that align with their specific energy consumption patterns.