Understanding Business Energy Tariffs in the UK

Business energy tariffs are often pitched as simple: a price per kilowatt hour and a standing charge. Easy, right?

Behind that neat-looking number lies a tangle of wholesale markets, network charges, and risk-based hedging that most suppliers would prefer you didn’t ask about. We’re here to change that.

Whether you’re running a single site or managing a 200-site estate, understanding your tariff type isn’t just admin — it’s the first step to controlling cost, risk, and carbon.

The Main Types of Business Energy Tariffs

1. Fixed Rate Tariff

What it sounds like:
A price per unit of energy fixed for a set contract term — usually 1, 2, or 3 years.

Why businesses choose it:
Stability. You know what you’re paying, regardless of what the wholesale market is doing.

What to watch for:
Fixed doesn’t always mean fully fixed. Pass-through costs (like network charges or levies) can still creep in if they’re not locked too.


2. Pass-Through Tariff

Also known as: Part-fixed or semi-flexible tariffs.

How it works:
You pay a (sometimes impressively low) rate for the wholesale energy, and everything else is passed through at cost — network fees, balancing charges, levies, the works.

Who it suits:
Businesses that want to ride market dips, or who have the tools to track and manage consumption proactively.

What to watch for:
Pass-through tariffs are like flying budget airlines — cheap headline price, but everything else is extra. If charges go up mid-contract (as they often do), so does your bill.


3. Flex (Flexible Purchasing) Tariff

Best suited to Larger energy users with half-hourly metering and internal energy management.

How it works:
You (or your energy partner) buy blocks of energy on the wholesale market over time. Costs can be optimised by buying in dips and spreading risk.

Why it’s powerful:
Flex buying puts you closer to the market. Done right, it can beat fixed deals — especially in volatile markets.

What to watch for:
It’s not for the faint-hearted. You’ll need data, risk appetite, and a partner who’s genuinely working in your interest (not just pushing volume).


4. Deemed or Out-of-Contract Tariff

How it happens:
You move into a new property, forget to renew your contract, or fall off the end of your deal — and suddenly you’re on a sky-high rate.

Why it’s bad:
These are the most expensive tariffs in the market — no negotiation, no control.

What to do:
Get off them ASAP. Even a basic fixed deal will likely be far cheaper.


5. Green or Renewable Tariffs

What they promise:
The energy you use is matched by renewable generation, or your supplier buys renewable certificates (REGO) to “green up” your usage.

Why they matter:
They help meet sustainability targets and look good on ESG reporting — but be careful what you’re actually buying.

What to watch for:
Some tariffs are 100% renewable in name only. It’s worth digging into whether it’s backed by real generation or just certificates.

Which Tariff Is Right for You?

It depends on:

  • Your energy usage patterns
  • The size and spread of your business
  • Appetite for market risk
  • Sustainability targets
  • How closely you want to track and optimise your energy spend

At Vester, we help you weigh all of this — with the transparency and intelligence the industry usually hides behind “commercial sensitivity.”

Your energy tariff isn’t just a line in your overheads — it’s a lever for control. Choosing the right one means fewer surprises, better budgeting, and smarter sustainability choices.

If you’re not sure what tariff you’re on — or whether it’s right for your business — you’re not alone. Most businesses aren’t told.

We analyse energy bills for businesses like yours every day — and we find overspending, hidden fees, and misaligned contracts more often than not.



We’ll review your bill and follow up with a clear, jargon-free breakdown — no upsell, no lock-in, just facts.