The structure of a UK business energy bill
Most commercial energy bills in the UK break down into roughly five categories of charge. The proportions vary by site type, supplier, and consumption pattern, but the categories are consistent.
- Wholesale energy cost – the actual electricity or gas you consumed, at the unit rate agreed in your contract
- Network charges – the cost of moving that energy across the national grid and local distribution network to your meter
- Levies and obligations – government-imposed charges that fund renewable energy programmes, capacity markets, and decarbonisation
- Metering and settlement charges – the cost of measuring your consumption and reconciling it with the wholesale market
- Third-party charges – your supplier’s fees for managing the contract, plus any data or metering operator fees
The wholesale energy cost is the main line item shaped by your contract negotiation. The other charges are largely statutory, regulatory, or set by parties beyond your supplier. Most of these costs vary based on your specific consumption profile and meter type.
Network charges explained
Network charges fund the physical infrastructure that delivers energy to your site. They are split into two main categories.
DUoS (Distribution Use of System)
DUoS charges fund the local distribution network – the regional cables, substations, and transformers operated by the Distribution Network Operator (DNO) for your area. There are 14 DNO regions in Great Britain, each with their own DUoS charging structure, and 19 Independent Distribution Network Operators (IDNOs) that operate nationwide to adopt, own, and maintain new local networks for housing or commercial developments.
DUoS rates vary by region, voltage level, time of day, and capacity. The time-of-day banding matters – red, amber, and green time bands carry different rates, with red bands (peak) costing significantly more. Sites with controllable load that can shift consumption away from red bands can save 10-20% on DUoS charges with minimal operational disruption.
TNUoS (Transmission Network Use of System)
TNUoS charges fund the high-voltage national transmission network operated by National Grid. Following Ofgem’s Targeted Charging Review reforms, most residual TNUoS charges for demand customers are now recovered through fixed-band charges based on site characteristics rather than real-time peak avoidance. For larger half-hourly metered sites, TNUoS remains a material cost, although the opportunity for traditional triad avoidance savings is significantly lower than it was historically.
BSUoS (Balancing Services Use of System)
BSUoS charges fund the real-time balancing of the electricity system by the National Energy System Operator (NESO). These costs arise when the system operator takes actions to maintain grid stability and match supply with demand. BSUoS is typically passed through to larger commercial customers as a variable non-commodity charge.
Levies and obligations
The UK government imposes several levies on commercial energy consumption to fund energy and decarbonisation policy.
Climate Change Levy (CCL)
Introduced in 2001 to encourage business energy efficiency. CCL is charged per kWh on electricity, gas, and other fuels – with separate rates for each. Energy-intensive businesses can apply for relief through Climate Change Agreements (CCAs), which reduce the CCL rate in exchange for energy efficiency commitments. CCL is a substantial line on most commercial bills. The rate is reviewed annually by HMRC.
Renewables Obligation (RO)
Funds large-scale renewable electricity generation. The RO is being phased out for new generation but ongoing payments continue. It appears on electricity bills only.
Feed-in Tariffs (FiT)
Funds smaller-scale renewable installations – typically commercial solar and small wind. Like the RO, the FiT is closed to new entrants but ongoing payments continue.
Capacity Market and Contracts for Difference (CfD)
The Capacity Market funds reliable generation capacity available to meet peak demand. CfD funds new low-carbon generation through contracts that guarantee a strike price. Both are passed through to consumers via supplier bills. Levies and obligations together typically account for 15-25% of a commercial electricity bill – they are non-negotiable, but also a source of frequent billing errors, particularly where exemptions or relief haven’t been correctly applied.
Metering and settlement
Every half-hourly metered electricity site in the UK has three parties beyond the supplier involved in its billing:
- MOP (Meter Operator) – installs and maintains the physical meter
- DC (Data Collector) – retrieves consumption data from the meter
- DA (Data Aggregator) – processes the data for settlement with the wholesale market
MOP/DC/DA charges are passed through to the customer, usually as separate line items on the bill. They vary by provider, contract length, and meter type. Half-hourly settlement charges are the costs associated with reconciling actual consumption with the wholesale market – often the most complex part of a commercial bill, and the part most likely to contain errors. Settlement disputes can run for months and result in significant retrospective adjustments.
Third-party charges
Beyond the regulated and wholesale costs, your bill will include supplier management fees, and potentially broker fees if your contract was sourced through a broker. Most UK energy brokers earn between 0.5p and 2p per kWh on electricity contracts, embedded in the unit rate. On a 5 GWh contract, that’s between £25,000 and £100,000 over the contract term – paid by you, often without disclosure. Independent brokers like eyebright operate on a transparent fee basis where commission is disclosed and contractually fixed. VAT is charged at 20% on most commercial supplies, with a reduced rate of 5% for some smaller sites.
The errors that hide in the detail
With all this complexity, billing errors are common. The most frequent sources we see in our audit work:
- Wrong DUoS band classification – sites mis-categorised as a different DUoS charging tier than they should be
- CCL applied where exemptions exist – particularly common for energy-intensive industries with CCA agreements that aren’t reflected in the bill
- Capacity charges on sites with reduced authorised capacity – capacity that’s been reduced administratively but not reflected in the network operator’s records
- MOP/DC/DA charges duplicated or mis-applied – particularly after supplier switches
- Settlement run errors – retrospective adjustments missed or applied incorrectly
- Estimated readings billed as actual – meters not being read at the agreed frequency, with estimates accumulating into significant over- or under-billing
Finding these errors requires forensic line-by-line analysis – which is exactly what a revenue recovery audit is designed to do.
Think your bills might contain errors?
Request a free audit. We analyse your billing line by line and recover overcharges on a no-win, no-fee basis.
What to do with all this
One. When you receive a commercial energy bill, the unit rate is rarely the most important number. Look at the proportions: if non-commodity charges are above 50% of the total, you have material exposure to network and levy costs that procurement strategy alone cannot address.
Two. Bill complexity is not optional – but understanding what each line means is. Anyone signing off commercial energy bills should be able to identify the major categories, even if they can’t audit every line item.
Three. If you’ve never had your bills independently audited, there’s a reasonable chance there are errors hiding in the detail. The cost of an audit is typically paid for many times over by the recoveries it identifies.
