What percentage of an electricity bill is the wholesale cost in the UK?

The wholesale electricity cost typically represents 30–45% of the total unit rate under Ofgem's price cap, though this varies significantly by quarter depending on market conditions. During the energy price crisis of 2021–2023, wholesale costs made up a higher share as market prices surged. Ofgem publishes the exact wholesale allowance in pence per kWh each quarter in its cap determination documents.

How do I find Ofgem's published wholesale allowance?

Ofgem publishes quarterly price cap determination documents at ofgem.gov.uk under the 'Price Cap' section. Each document includes an Annex or detailed breakdown showing each cost component in pence per kWh, including the wholesale gas and electricity allowances. These figures are also summarized by energy comparison sites and consumer groups.

Why does the wholesale price affect my electricity bill even on a fixed tariff?

If you're on a fixed tariff, your unit rate is locked for the duration of the fix — you are directly insulated from wholesale movements. However, your supplier hedged the energy at certain forward prices when setting that fixed rate. If you're on a variable or standard tariff (SVT), you're subject to the price cap, which updates quarterly to reflect observed wholesale prices. Fixed tariffs pass the wholesale risk to the supplier; variable tariffs pass it to the consumer.

Will the wholesale share of my electricity bill fall as renewables expand?

Potentially, but not directly or quickly. UK electricity prices are currently set at the margin by the most expensive generator running at any given moment — which is often a gas-fired power station. As more zero-marginal-cost renewables enter the grid, gas plants run less often, reducing their influence on the price. Full transition to a renewables-dominated grid with reformed electricity markets could significantly reduce the wholesale component, but this depends on market reform policy as well as capacity growth.

How to Calculate the Wholesale Share of Your Electricity Bill

Learn how to identify and calculate the wholesale electricity cost component of your UK energy bill — using Ofgem's published allowances, unit rates, and consumption data.

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What Is the Wholesale Share of an Electricity Bill?

The wholesale share is the portion of your electricity unit rate (pence per kWh) that reflects what your energy supplier paid to purchase electricity from the wholesale market. It is one of several components stacked to build your final unit rate.

The Components of an Electricity Unit Rate

Ofgem's price cap decomposes into these components (approximate):

Component	Approx. Share
Wholesale electricity cost	30–45%
Network charges (TNUoS + DUoS)	20–25%
Environmental / policy levies	15–20%
Supplier operating costs	8–12%
VAT (5%)	~4–5%
Profit allowance	1–2%
Bad debt allowance	1–2%

The exact shares change each quarter as Ofgem revises the cap components.

Step-by-Step: Calculating the Wholesale Share

Step 1 — Find the Current Unit Rate

Your energy bill shows a unit rate in pence per kWh (p/kWh). Example: 24.5p/kWh electricity.

Step 2 — Find Ofgem's Published Wholesale Allowance

Ofgem publishes detailed cap structure documents each quarter at ofgem.gov.uk. These include a line-by-line breakdown of the unit rate, including the wholesale electricity cost component.

Example from a recent quarter: Wholesale electricity allowance = 7.4p/kWh

Step 3 — Calculate the Share

Wholesale Share % = Wholesale Allowance / Unit Rate × 100

Example: - Wholesale allowance: 7.4p - Total unit rate: 24.5p - Wholesale Share = 7.4 / 24.5 × 100 = 30.2%

Step 4 — Calculate the Monetary Amount in Your Bill

If you used 3,500 kWh/year: - Total bill (excl. standing charge) = 3,500 × 24.5p = £857.50 - Wholesale portion = 30.2% × £857.50 = £258.97/year

Why Does the Wholesale Share Change?

Factor	Effect
Gas price movements	UK electricity prices track gas (gas peakers set marginal price)
Renewables deployment	More cheap renewables reduce wholesale costs over time
Interconnector capacity	UK imports from Europe; European prices affect UK markets
Seasonal demand	Winter demand peaks drive prices up in winter reference periods

Interpreting Year-on-Year Changes

If your bill increased from £1,200 to £1,600 over two years: - Check what changed in the wholesale share component from Ofgem's quarterly publications - Separate wholesale-driven increases from network or levy increases - This distinction matters for forecasting: wholesale costs are market-driven and volatile; network and levy costs are policy-driven and more stable

Frequently Asked Questions

What percentage of an electricity bill is the wholesale cost in the UK?: The wholesale electricity cost typically represents 30–45% of the total unit rate under Ofgem's price cap, though this varies significantly by quarter depending on market conditions. During the energy price crisis of 2021–2023, wholesale costs made up a higher share as market prices surged. Ofgem publishes the exact wholesale allowance in pence per kWh each quarter in its cap determination documents.
How do I find Ofgem's published wholesale allowance?: Ofgem publishes quarterly price cap determination documents at ofgem.gov.uk under the 'Price Cap' section. Each document includes an Annex or detailed breakdown showing each cost component in pence per kWh, including the wholesale gas and electricity allowances. These figures are also summarized by energy comparison sites and consumer groups.
Why does the wholesale price affect my electricity bill even on a fixed tariff?: If you're on a fixed tariff, your unit rate is locked for the duration of the fix — you are directly insulated from wholesale movements. However, your supplier hedged the energy at certain forward prices when setting that fixed rate. If you're on a variable or standard tariff (SVT), you're subject to the price cap, which updates quarterly to reflect observed wholesale prices. Fixed tariffs pass the wholesale risk to the supplier; variable tariffs pass it to the consumer.
Will the wholesale share of my electricity bill fall as renewables expand?: Potentially, but not directly or quickly. UK electricity prices are currently set at the margin by the most expensive generator running at any given moment — which is often a gas-fired power station. As more zero-marginal-cost renewables enter the grid, gas plants run less often, reducing their influence on the price. Full transition to a renewables-dominated grid with reformed electricity markets could significantly reduce the wholesale component, but this depends on market reform policy as well as capacity growth.

Last updated 7/28/2026