The way electricity is settled across Great Britain is changing, and that change could make the shape of a business’s electricity demand increasingly important.

Market-wide Half-Hourly Settlement (MHHS) is now being rolled out across the electricity market. Migration began in October 2025 and is scheduled to complete in May 2027.

At its simplest, MHHS means electricity suppliers will increasingly be settled using customers’ actual consumption in each half-hour period, rather than relying on the consumption profiles historically used for many smaller customers.

It is important to distinguish settlement from billing. MHHS does not mean every business will automatically move to a half-hourly or dynamic tariff. What it does is give suppliers a much clearer financial signal about the cost of supplying electricity at different times of the day.

That creates an incentive for suppliers and other market participants to develop tariffs and services that encourage customers to use electricity more flexibly.

From how much electricity to when

For businesses, this reinforces an important point: annual electricity consumption only tells part of the story.

Consider two properties that each consume 500,000 kWh of electricity a year.

One has relatively consistent daytime demand. The other has sharp peaks in consumption at particular times.

Their annual consumption may be identical, but their electricity cost exposure and the potential value of onsite generation, battery storage and changing when electricity is imported from the grid can be very different.

As electricity pricing becomes more sensitive to when energy is consumed, understanding that half-hourly load profile becomes increasingly valuable.

This is particularly relevant as businesses electrify more of their operations through EV charging, heat pumps and other technologies. Electrification may increase electricity consumption, but when that additional demand occurs can materially affect the result.

 

Better data should mean better investment decisions

This is where MHHS aligns closely with the approach already taken by OnGen Expert.

OnGen Expert uses property-specific energy demand and tariff data to objectively assess the feasibility of onsite renewable energy and storage technologies.

Rather than starting with the assumption that a business should install solar panels, a battery or another particular technology, the assessment starts with the property itself.

How much electricity is being consumed? When is it being consumed? How well would onsite generation match that demand? What size of system provides the strongest financial return? Are there technical or property constraints that could affect deployment?

The result is a more robust investment case based on the characteristics of the individual site rather than generic assumptions.

The start of a wider change

MHHS is only part of a much wider evolution in how businesses can interact with the electricity system.

Greater access to half-hourly data, more time-sensitive electricity pricing and increasing demand for flexibility create new opportunities, but also make energy investment decisions more complex.

Over the coming weeks, we will look in more detail at flexibility services, how businesses can reduce costs through load shifting, the role of the Capacity Market, and P415 and the opportunities it creates for behind-the-meter assets.

The common thread is simple: electricity is becoming increasingly valuable at different times.

Understanding when you consume, generate and store it will therefore become just as important as understanding how much you use.

Want to understand what your half-hourly electricity data could mean for onsite energy investment? Explore OnGen Expert or request a demonstration.