Coverage
Every charge. Its source. Firm or held.
Commodity is the easy half. The rest of a UK business energy invoice is network, balancing, policy and tax, each priced from its own published source on its own calendar. This page lists every charge the engine models, where the expected figure comes from, and the lines it holds rather than guesses.
- Rebuilt from the source that set the charge, not compared with last month’s bill
- Held for confirmation where no public source exists, with the reason stated
- No silent rounding: the only rounding anywhere is the final whole-pence line
33
charge types modelled, counted from the engine’s own catalogue
11
priced bottom-up from the published source, no contract rate involved
3
held rather than guessed, each named below with its reason
Simplest Energy validates 33 charge types across UK business electricity, gas and water bills. 11 are priced from published reference data with no contract rate involved: the Schedules of Charges of all 14 GB distribution networks, NESO’s TNUoS, BSUoS and AAHEDC tariffs, the LCCC’s CfD and Nuclear RAB levy rates, the Capacity Market supplier charge and Elexon’s settlement prices. The Climate Change Levy and VAT come from the statutory rate in force. Everything else is rebuilt from the customer’s own contract, with the quantities always taken from the meter, never from the bill. Where a figure has no public source, RCRC for example, the line is held for confirmation rather than guessed and the page below says so.
Supply
What the supplier charges for the energy itself and for the supply point.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| Unit rate | Your contract, per meter, per time band | Your contract | Firm |
| Standing charge | Your contract’s daily charge, multiplied by the billed days of the period | Your contract | Firm |
| Metering | Your contract’s agreed MOP, DC or DA charge, priced per day across the billed days | Your contract | Firm |
Network
Use of the distribution and transmission systems, from published schedules.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| DUoS | The DNO’s published Schedule of Charges, resolved per meter per day: unit rates by band, fixed, capacity, exceeded capacity | Published source | Firm |
| Available capacity | The same schedule’s availability rate against the meter’s own agreed kVA, per day | Published source | Firm |
| Reactive power | The same schedule, with the DCUSA 0.95 power-factor allowance against the meter’s own kVArh | Published source | Firm |
| TNUoS | NESO’s published tariffs; the TCR band derived from the meter and shown | Published source | Firm |
London Power Networks, weekday00:00–07:0007:00–11:0011:00–14:0014:00–16:0016:00–19:0019:00–23:0023:00–24:00
Published LPN time bands. The demand shown is an illustrative weekday shape.
Balancing and market
Keeping the system in balance, and the cost of settling the half-hours.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| BSUoS | NESO half-hourly rates to March 2023, fixed windows since; drafts marked provisional | Published source | Firm |
| Imbalance | Elexon’s published imbalance prices per settlement period | Published source | Held until the contract’s allocation method is confirmed |
| RCRC | Priced from Elexon settlement data | Published source | Always held: no public feed publishes RCRC per settlement period |
| Capacity Market | Customer’s own winter-peak half-hours at the derived rate | Published source | Delivery years from 2024/25 are held until the final rate is determinable |
| CM settlement costs levy | Your contract’s agreed p/kWh on the period’s consumption; an administration levy the EII exemption does not touch | Your contract | Firm |
| Elexon and BSC charges | Your contract’s agreed p/kWh on the period’s consumption | Your contract | Firm |
Policy and levies
Government policy costs passed through to the meter.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| CfD supplier obligation | LCCC interim levy rate, then the reconciled daily rates | Published source | Firm |
| CfD operational costs levy | Your contract’s agreed p/kWh on the period’s consumption; an administration levy the EII exemption does not touch | Your contract | Firm |
| Renewables Obligation | Your contract’s agreed p/kWh, with any certified EII exempt proportion removed first | Your contract | Firm |
| Feed-in Tariff | Your contract’s agreed p/kWh, with any certified EII exempt proportion removed first | Your contract | Firm |
| Nuclear RAB | The LCCC’s published quarterly levy rate in pounds per MWh, on metered consumption with no loss adjustment | Published source | Firm |
| AAHEDC | NESO’s published national tariff, applied to the loss-adjusted volume where the contract passes it through | Published source | Firm |
| EII support levy | Your contract’s agreed p/kWh for the levy that recovers the exemption scheme’s cost | Your contract | Firm |
| Combined policy levies | Your contract’s combined rate where the supplier bills the policy levies as one line; only the total is checkable until they are itemised | Your contract | Firm |
Gas
Commodity, capacity and the standing customer charge.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| Gas commodity | Your contract’s agreed p/kWh on the period’s throughput; the GDN’s own schedule is not reference-priced | Your contract | Firm |
| Gas capacity | Your contract’s agreed rate against the meter’s registered SOQ, per day; the GDN’s own schedule is not reference-priced | Your contract | Firm |
| Gas customer charge | Your contract’s fixed daily charge across the billed days; the GDN’s own schedule is not reference-priced | Your contract | Firm |
Water and sewerage
Volumetric and standing charges for water, sewerage and drainage.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| Water volumetric | Your contract’s rate per cubic metre against the period’s metered volume | Your contract | Firm |
| Water standing charge | Your contract’s daily charge across the billed days | Your contract | Firm |
| Sewerage volumetric | Your contract’s rate per cubic metre against the agreed return-to-sewer share of the metered volume; the share is always explicit, never assumed | Your contract | Firm |
| Sewerage standing charge | Your contract’s daily charge across the billed days | Your contract | Firm |
| Surface water drainage | Your contract’s daily charge across the billed days | Your contract | Firm |
| Trade effluent | Your contract’s rate per cubic metre against the agreed trade effluent share of the metered volume | Your contract | Firm |
Also handled
Contract-specific lines that belong to no published category.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| Bespoke formula | The contract’s own arithmetic, evaluated safely against the bill’s rate, consumption, days, capacity and totals | Your contract | Firm |
Tax
Charged on the lines above, so it moves whenever they do.
| Charge | How it is validated | Basis | Firm or held |
|---|---|---|---|
| Climate Change Levy | HMRC statutory rate table; EII, VAT and CCA reliefs kept distinct | Statutory rate | Firm |
| VAT | The percentage in force, applied once to the net total with CCL included | Statutory rate | Firm |
And around the lines themselves: Line-loss factors gross the metered volume up before any of this is priced, and EII exemption and CCA relief then reduce the levies and the Climate Change Levy in turn.
Now put an invoice against it.
A short call, then we validate a real bill of yours against every source on this page and walk through what the engine found, line by line.