Tariffs
Commercial energy tariffs
Commercial time-of-use and half-hourly tariffs, explained. Why the structure of your tariff matters as much as the rate, and how to match both to how your sites actually use energy.
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Most tariff advice reduces to one number: the unit rate. That is the wrong lens for any commercial site, and it fails completely for half-hourly settled sites, where the shape of your consumption is priced, not just the volume.
Structure, then rate
A tariff is a risk contract. A fixed flat rate transfers all timing risk to the supplier, and the supplier charges for it. Time-of-use structures hand some of that risk back to you, priced accordingly. Which side of that trade you should be on is a property of your data: how predictable your usage is, when it happens, and what you can shift. Start with half-hourly data, then time-of-use and day-ahead pricing.
Here is the mismatch most sites are living with. The tariff was never chosen against the consumption. It arrived through a renewal, a broker’s default, or the last occupier, and it has never been tested against how the site actually uses power. The result is a structure built for an average business, applied to a specific one.
That gap is where avoidable cost sits, and switching supplier does not close it. A business can move supplier three times and stay on the wrong structure throughout, because the structure, flat rate against time-of-use against day-ahead, is a separate decision from who sends the bill. Suppliers and brokers rarely raise it. There is no commission in telling a customer their tariff shape is wrong.
The only way to know is to price your own half-hourly data against each candidate structure and total the result. Across one customer portfolio of supply points, moving to a day-ahead passthrough tariff cut commodity cost by £86,779 a year, a 12.0% reduction, with no capital spent and no change to how the sites ran. The saving was not a keener rate. It was a better fit.
The parts of the bill that are not energy
A commercial bill stacks wholesale energy, network charges, policy costs and margin. Network charges alone reward or punish consumption timing, independently of your supply rate. See network charges. If you generate on site, the export side has its own market: see export tariffs.
Matching is the work
Vester’s role is matching: your profile, against the structures actually available, priced from your own meter data. Whole-market access runs through a market-access partner, not through us. We take no commission, earn nothing from any supplier, and you pay us a disclosed fee directly.
Book a fixed-fee review or request a benchmark of what you should be paying.
In this section
Half-hourly data: the foundation of tariff decisions
What half-hourly consumption data is, how to get yours, and why no tariff decision should be made without it.
Time-of-use tariffs for commercial sites
How time-of-use tariffs work for UK commercial sites, which load profiles they suit, and how to test the fit before committing.
Day-ahead pricing
How day-ahead pass-through pricing works for UK businesses, who it suits, and how to judge the risk honestly.
Network charges explained
What DUoS, TNUoS and balancing charges are, how they reach your business energy bill, and which of them you can still influence.
Export tariffs
How UK businesses get paid for exported solar or battery power, and why the export arrangement deserves as much scrutiny as the import one.
A fixed tariff is an insurance premium. If you can operate flexibility, you may not need to pay it.
Frequently asked questions
How do I compare commercial energy tariffs for a half-hourly metered site?
Not on headline rate. A half-hourly site is priced against its consumption profile, so the same tariff can be cheap for one business and expensive for another. Comparison means applying each candidate tariff structure to your own half-hourly data and totalling the result. Anything less is guesswork.
What is a time-of-use tariff?
A tariff where the unit rate varies by time of day, broadly following wholesale prices and network charges. If your consumption is flexible, or already concentrated in cheaper periods, a time-of-use structure can cost less than a flat rate. If it is concentrated in peaks, it will not. Your data decides.
Why does my tariff structure matter as much as the rate?
Because a flat rate is a form of insurance: the supplier prices in the risk of when you might consume. If your usage pattern is predictable or controllable, you are paying a premium for cover you do not need. Structure is where that premium is won or lost.