Market-Wide Half-Hourly Settlement sounds like the sort of electricity-market reform most businesses should be able to leave to suppliers.

To an extent, they can.

But that does not mean energy buyers should ignore it.

The change alters how electricity suppliers are settled for the energy their customers actually use. Instead of much of the market relying on estimated consumption profiles, smart and advanced meter data allows consumption to be measured much more accurately across each half-hour of the day. Ofgem's intention is that this gives suppliers a clearer picture of the true cost of serving customers and encourages tariffs and services that reward more flexible electricity use.

For business buyers, the important question is therefore not simply:

“Has MHHS happened?”

It is:

“What does our actual consumption profile now mean for the way suppliers price and manage our electricity?”

MHHS is here, but the transition is still happening

There is an important distinction between MHHS having arrived and the entire market having completed migration.

Industry-wide migration began in October 2025. By July 2026, the MHHS Programme reported that more than half of industry MPANs had migrated, and in August it announced that the first suppliers had completed their migration activity.

The next major milestone is 28 October 2026, when all suppliers must be able to accept MPANs under the new Target Operating Model. Full migration of MPANs is scheduled for completion by 7 May 2027, followed by the move to the new settlement timetable in July 2027.

So businesses are operating through a transition period.

For organisations with large or complicated electricity portfolios, that makes now a sensible time to check whether their data, metering and procurement arrangements are ready for the market they are moving into.

First, what MHHS does not mean

Perhaps the most important misconception to avoid is that half-hourly settlement automatically means businesses will be charged a different electricity price every half hour.

It does not.

Settlement is the process used by the electricity market to reconcile the electricity that suppliers purchase with the electricity their customers actually consume.

Your commercial electricity contract still determines how you pay for that electricity.

A fully fixed contract does not automatically become a half-hourly spot contract because of MHHS.

But the change does give suppliers a much clearer view of the cost associated with serving different consumption profiles.

And over time, that is likely to make when you consume electricity increasingly relevant to energy procurement, alongside the traditional question of how many megawatt hours you consume each year.

1. Is your electricity data actually reliable?

This is where I would start.

MHHS depends on more granular consumption information.

That makes poor data harder to dismiss as an administrative inconvenience.

Businesses should know:

• which MPANs form part of their portfolio

• which meters are smart, advanced or traditionally half-hourly metered

• whether half-hourly consumption data is being collected consistently

• whether there are gaps or estimated periods within that data

• whether the site information held by suppliers and other market participants is correct

• who is responsible for resolving metering or data-quality problems

For a multi-site property portfolio, this can be more difficult than it sounds.

Sites change. Tenants move. Meters are replaced. Supplies become vacant. New connections appear. Old MPANs sometimes remain in portfolio records long after somebody assumed they had disappeared.

Better settlement data is useful only if the underlying portfolio information can be trusted.

2. Do you understand your load shape, not just your annual consumption?

Historically, an energy tender might begin with a figure such as:

“This portfolio consumes 15 GWh of electricity each year.”

That remains important.

But two organisations consuming exactly the same annual volume can have very different electricity profiles.

One might consume heavily during weekday peak periods.

Another might operate overnight.

A third may have substantial weekend demand.

A property portfolio could contain offices, retail space, common areas, electric vehicle charging, heat pumps and other loads behaving differently across the day.

MHHS gives suppliers a stronger incentive to understand those differences because settlement more accurately reflects actual half-hourly consumption. Ofgem specifically designed the reform to expose suppliers more closely to the cost of serving customers at different times.

Energy buyers should therefore start treating load shape as part of their energy procurement data, rather than simply something produced by the meter after the tender is complete.

3. Ask suppliers how your consumption profile affects the offer

This is where energy tender preparation may need to evolve.

When comparing electricity contracts, buyers should understand what assumptions suppliers are making about the portfolio's consumption profile.

That does not mean every procurement exercise needs to become enormously technical.

It does mean asking sensible questions.

Has the supplier priced using the actual half-hourly profile?

How does the customer's load shape affect the price?

Are there particular consumption periods creating additional cost or risk?

How would a material change in consumption affect the contract?

Does the supplier offer products that allow the customer to benefit from greater flexibility?

And if different suppliers treat that exposure differently, are you genuinely comparing like with like?

The cheapest headline commodity rate may not tell the entire story.

4. Look again at where flexibility may exist

One of the wider objectives behind MHHS is to encourage customers to move electricity consumption towards periods when supplying it is cheaper or more efficient.

Ofgem expects the reform to support products such as time-of-use tariffs, automated demand flexibility, battery storage and other technologies that allow customers to respond to price signals.

For some businesses, there may be very little flexibility.

A building still needs to operate when people are using it.

But others may have loads that can move without affecting the underlying operation.

Electric vehicle charging is an obvious example.

Battery charging and discharging may be another.

Heating, cooling, refrigeration or certain industrial processes might also offer varying degrees of flexibility.

The sensible question is not whether every business should suddenly start trading electricity.

It is whether the organisation has meaningful flexibility that its current energy procurement strategy ignores.

5. Do not forget the invoice

More sophisticated settlement does not remove the need for energy invoice validation.

If anything, increasing complexity makes effective validation more important.

Businesses should still be checking that invoices reflect the contract they actually signed, that meter and consumption information is correct and that unexpected charges or consumption movements are investigated rather than automatically paid.

For organisations with many meters, this becomes particularly important.

Half-hourly data can create a much richer picture of how electricity is being consumed.

It can also create considerably more data to manage.

The objective should be to turn that information into better control, not simply a larger spreadsheet.

MHHS should prompt a wider procurement conversation

Market-Wide Half-Hourly Settlement is fundamentally an industry reform.

Most business buyers do not need to become experts in the electricity settlement process.

But they should understand what sits behind it.

The electricity market is moving towards a model in which the timing of consumption can be reflected more accurately in the cost suppliers face.

That makes several things more important:

Good metering.

Good consumption data.

A clear understanding of load shape.

Energy contract structures that reflect the organisation's actual requirements.

And an energy procurement strategy that considers not only how much electricity the business uses, but increasingly when it uses it.

For some organisations, MHHS may make relatively little immediate difference to the way electricity is purchased.

For others, particularly large multi-site portfolios, businesses electrifying heat or transport, or organisations with flexible demand, it could create much more interesting procurement choices.

The starting point is not to change the contract simply because the market has changed.

It is to make sure you understand your data well enough to know whether you should.