Multi-site and large business energy: how it works

When do you count as "large" or multi-site?

There is no single official line where a business becomes "large" for energy buying. What changes is the way you are priced and the protections that apply. Ofgem's rules use size tests. A microbusiness has fewer than 10 employees and turnover or balance sheet of up to €2 million, or uses under 100,000 kWh of electricity or 293,000 kWh of gas a year. A small business has fewer than 50 employees and turnover up to £6.5 million or a balance sheet up to £5 million, or uses up to 200,000 kWh of electricity or 500,000 kWh of gas. Pass those tests and you are into the territory where fewer of the special protections, such as the 12-month back-billing limit (domestic and microbusiness only), apply. See what counts as a microbusiness and the extra protections they get.

In practice, comparison sites tend to treat a business as "large" at higher usage, and the exact numbers differ by site, so treat any one site's cut-off as indicative. If your annual use is heading towards the hundreds of thousands of kWh, or you run many sites, assume you will be priced individually.

Half-hourly meters

A half-hourly meter records your use every 30 minutes. Larger electricity users in profile classes 5 to 8 have had to be settled on actual half-hourly data since April 2017, and under industry settlement rules a site whose maximum demand averages over 100 kW (based on its three highest monthly peaks) must be moved to half-hourly metering; and you can see your profile class in the first two digits of the MPAN top line. See electricity profile classes explained and half-hourly meters explained.

The wider industry change is Market-wide Half-Hourly Settlement (MHHS). Migrations began on 22 October 2025, with full implementation expected by May 2027, according to the industry body Elexon. For a multi-site business the practical effect is that more of your sites will be billed on actual half-hourly use, not estimates, over this period. Read MHHS for business for the detail.

Why it matters to you

• Your usage pattern, not just the total, can influence what you pay.
• Network charges (see non-commodity charges explained) can be driven by when you use power, so spiky sites cost more to serve.
• Data lets you spot waste. See energy monitoring for business.

Gas: peak day demand and daily limits

Larger gas users are often offered a peak day demand arrangement. As comparison-site guidance describes it, a maximum daily quantity (MDQ) caps how much gas a site can draw on any day, with penalties if you exceed it. If you are heavy on cold days, a cap set too low can be costly, and one set too high means paying for capacity you do not use. Ask any supplier or adviser how the cap is set, what the penalty is and whether it can be revised mid-contract.

Check the unit on your gas meter first, as many sites record cubic metres. Our gas units to kWh converter helps you compare like with like.

Contract types for bigger buyers

Type	How it works	Suits
Fixed	Energy unit price locked for the term	Businesses that want certain budgets
Pass-through	Energy cost fixed, but network and policy charges can change during the term	Large users who accept some cost movement
Flexible or purchase-in-stages	You buy volume in several chunks over time, or follow the market	Buyers with time, risk appetite and market advice
Interruptible	Lower price in return for agreeing to be cut off at times	Sites that can genuinely stop during peaks

Our pages on pass-through vs fixed charges and fixed vs flexible contracts explain the trade-offs. Flexible buying can lower or raise your costs. Nobody can promise a saving, so only do it with a clear policy on how much price risk you will tolerate.

One contract for many sites

Putting sites on one agreement can bring practical benefits:

• One bill. Consolidated billing can cut admin, especially if you have a bookkeeper.
• One end date. Aligned renewals mean one deadline instead of several, so you are less likely to slip onto out-of-contract rates.
• Negotiating weight. Some suppliers will price a bigger portfolio differently, though that is not guaranteed.

Worked example

A small chain has three shops with a combined 90,000 kWh of electricity a year and three contracts ending in March, July and November. Suppose each site is on a 60p/day standing charge:

• Standing charges: 3 × 365 × £0.60 = £657 a year.
• If the July contract is missed and rolls to an out-of-contract rate, using the October 2026 comparison-site averages (40.0p against 28.4p, a gap of 11.6p), a site using 30,000 kWh would pay 30,000 × £0.116 = £3,480 more over a year in unit charges alone.

Aligning all three to a single end date turns three deadlines into one. Check whether your supplier allows sites to be added to or removed from the agreement, and what happens if you close a shop. Our guide to switching energy for multiple sites covers the mechanics.

Who should help you buy?

For a handful of sites, a broker or direct supplier quote may do. For a larger portfolio, you may use an energy consultant who is paid a fee rather than commission. Our page on broker versus energy consultant sets out the difference. Whoever you use, ask how they are paid. For microbusiness contracts, broker costs passed through the supplier must appear in the Principal Terms, and since 1 October 2024 that extends to all non-domestic contracts. A broker you pay directly need not be declared in the supplier's terms, so ask for their fee in writing. Brokers are not yet directly regulated by Ofgem, which says it is preparing to regulate them. Our page on whether brokers are regulated has the current position.

Tax and cost points across sites

• Climate Change Levy: 0.801p/kWh from 1 April 2026 and 0.827p/kWh from 1 April 2027. Some energy-intensive sectors can get a discount through a climate change agreement.
• VAT: Standard 20%, reducible only for qualifying use at a given premises, and the certificate is per premises. See VAT and CCL.
• Capacity charges: Larger electricity supplies may carry charges linked to agreed capacity. See supply capacity and kVA charges.

Do not assume that every protection that applies to a single-shop microbusiness applies to your group. The guidance we checked does not spell out how usage is counted across several sites, so ask your supplier in writing which rules it applies to each meter.

Next steps

1. List every meter: site, MPAN or MPRN, annual kWh, supplier and end date.
2. Check which sites are half-hourly and which fuels have a daily cap.
3. Decide your risk appetite for fixed versus flexible buying.
4. Get written quotes with fees disclosed, then align end dates.