Market Wide Half Hourly Settlement (MHHS)
Market Wide Half Hourly Settlement (MHHS) is a new electricity industry initiative led by Ofgem, the energy regulator. It will bring several benefits to domestic and business consumers and help to green up the electricity grid.
This is because the more accurate the usage data energy suppliers have, the better we can anticipate our customers’ energy requirements. That means a more flexible grid and potentially lower operating costs from fewer manual meter readings and engineer visits, which would hopefully be passed on to customers by suppliers across the industry.
MHHS will also enable suppliers to offer time-of-use tariffs, where energy is cheaper when demand is low at specific times of the day, as well as giving customers clearer and more useful information about their energy consumption.
What is Market Wide Half Hourly Settlement?
At present, most electricity usage data is not taken very frequently. The National Grid knows how much energy is being used across the country and where – but not when, which is vital for creating a greener, more flexible energy grid.
Having more information about electricity use would help energy companies match up the energy they buy as a supplier to the energy used by their customers. This is a process called ‘settlement’ - the more accurate it is, the more efficient it is.
For this reason, from May 2027, all consumers will have their electricity consumption ‘settled’ every half-hour.
It will also help us plan as a country for future energy needs by identifying trends and patterns in energy consumption – and it will play a key role in getting Britain to Net Zero by identifying where infrastructure improvements are most needed.
Importantly, MHHS doesn’t mean that you have to agree to a meter reading every half an hour (unless you’re on a tariff that requires it), but smart meter customers who take part will be playing a pivotal role in fighting climate change.
MHHS FAQs
No, your current tariff will stay the same – this is just about how energy consumption is recorded.
Overall, Ofgem predicts that MHHS will bring cheaper bills for consumers in the UK in the future, thanks to half-hourly meter readings enabling smarter and more flexible services such as time-of-use tariffs, reduced peak demand and lower system costs.
When you install a smart meter, you’re helping us to get another step closer to a greener Britain. Plus, you’ll never have to read your meter again or send us a reading, you’ll always receive accurate bills (never estimated), and you’ll be able to access smart tariffs and save money.
You can read more about smart meters or register for a free smart meter upgrade now through your online account or by emailing home@ecotricity.co.uk.
You can opt out of providing half-hourly data if your tariff allows. If you do this, we’ll estimate your half-hourly data but this won’t be as accurate – and it won’t help us to green up the grid.
You can’t opt out if you're a domestic customer on a fixed or EV tariff, or if you’re a business customer that isn’t classified as a microbusiness.
If your tariff depends on half-hourly data (for example, time-of-use or dynamic tariffs), you should carefully review the principal terms of your contract before opting out. Opting out could affect how your energy charges are calculated or which tariffs are available to you.
Business customers: Only microbusinesses can opt out of providing half-hourly data. It will be compulsory for all other business customers.
Smart meters can record energy usage on a half-hourly basis and securely pass that on to your supplier, so a smart meter is best for providing accurate data.
However, you don’t have to change your meter (unless your tariff requires it). Instead, we’ll estimate your half-hourly data from your monthly readings. You can’t opt out of this, as it’s a mandatory industry change led by Ofgem.
No, MHHS only affects electricity.
We’re aiming to begin migrating our customers to MHHS from October 2026.