About market-wide half hourly settlement.
How it works.
Half hourly data settlement allows us to access your electricity usage data every 30 minutes via your smart meter and use this data for settlement.
Until now, smart electricity data for settlement has been based on monthly readings - meaning we can settle on how much energy has been used but not when it’s used.
MHHS will help suppliers forecast and buy the energy customers need more accurately - better forecasting will help us to make more electricity purchases from renewable sources rather than expensive, carbon-heavy generators.
This will help stabilise the grid, reduce carbon impact, and may ultimately lower the cost of energy for customers.
Ofgem analysis predicts that MHHS will bring net benefits for consumers in GB of between £1.6bn and £4.5bn over the period 2021-2045.
Benefits of half hourly settlement.
More accurate billing.
Improved grid efficiency.
Support for renewable energy.
Reduced energy costs.
Half hourly settlement opens the door for new energy products and better tracking services - giving customers more insight on how they use energy which can help save money and carbon.
How does MHHS affect me?
We will start migrating customers to half hourly settlement in Autumn 2025.
If you have a smart (or advanced) meter changes to how your data is used will depend on your current tariff.
Time of use tariffs.
If you’re on a time of use tariff, your smart meter already automatically sends half hourly readings and we already use these for settlement.
You won’t be able to opt out because this is needed for the tariff to function correctly.
Other tariffs.
You'll default to half hourly data settlement if you’ve agreed a new tariff with us or have had a smart meter installed after November 2022. You could choose to opt out to daily readings.
If your smart meter was installed before November 2022 and you haven't agreed a new tariff with us since, your smart meter will default to daily. You can always choose to opt into half hourly or opt out to monthly readings if you prefer.
Export tariffs such as our Smart Export Guarantee (SEG) tariff.
If you get paid for your export, for example if you have a SEG tariff and generate electricity from solar panels, your export meter will automatically opt in to send half hourly readings.
How we protect your data.
We’ll always keep your data safe and won’t use it for other purposes without your permission. Visit our privacy policy to learn more.
Opting in (or out).
You can update your preferences online or get in touch to change your preferences.
If you’re waiting for a smart meter, you can change how often we collect this data after installation.
How smart meters help.
Smart meters can send electricity usage data every 30 minutes and we can use this data during the settlement process. Smart meters are also a great way to see how your home uses energy - they give you more control of your energy use and help you spot ways to save.
Don’t have a smart meter yet? Book an appointment and we’ll install one for you for free.
Changing energy costs.
The cost of buying wholesale electricity changes every 30 minutes. When demand is low we can use cheaper renewable sources like wind, wave and sun to power the grid.
But renewable energy only goes so far. When electricity demand is high (like in the evening) the grid has to rely on more expensive carbon-heavy fossil fuels.
Settlement and balancing.
The Balancing and Settlement Code (BSC) compares the amount of electricity we’ve bought as a business with the amount used by our customers.
Using estimated data means suppliers often under or over purchase electricity. To cover any imbalance, the BSC charges or pays us their default rates, which are usually to our (and therefore our customers’) financial detriment - this is called the settlement process.
Settlement has always happened daily - MHHS means it can now take place every 30 minutes, known as a half hourly settlement. We’ll only collect half hourly data from smart meters if the customer allows it or if it’s required. Traditional meters (non smart) aren’t affected.
What is balancing?
Balancing means the physical grid management - half-hourly data can allow for more precise demand forecasting, which can optimise grid operations and can better accommodate the intermittent nature of renewable energy sources. This makes, making it easier to integrate them into the grid, and reduce reliance on fossil fuel generation.