Reference tools
Calculate your energy costs, carbon footprint, and understand what you pay for
Four working tools built on Ofgem price-cap references, published carbon factors, and transparent teaching assumptions. Start here for consumer questions, then open the engineering tools only when you need heavier calculations.
Energy Bill Calculator
Calculate your annual electricity bill based on Ofgem price cap rates. Enter your consumption and tariff to see the breakdown: energy charges, standing charge, VAT, and total cost.
Carbon Footprint Estimator
Estimate the carbon emissions embedded in your electricity use based on GB grid composition. Emissions vary by hour: windy days are near-zero, gas-heavy periods reach 400+ gCO2/kWh.
GB Generation Mix Visualiser
Explore what powers the GB electricity grid. These are actual generation technologies and their approximate share of production. Real-time data available from Elexon BMRS and ESO data portal.
| Technology | Share | Carbon intensity | Notes |
|---|---|---|---|
| Nuclear | 18-22% | 12 gCO2/kWh | Existing fleet (Magnox, AGR) being retired. Hinkley Point C under construction. |
| Onshore wind | 15-20% | 11 gCO2/kWh | Highly variable. 40%+ capacity factor in Scotland; lower in Southern England. |
| Offshore wind | 10-15% | 12 gCO2/kWh | Higher capacity factor (45-50%). Growing fast; planning pipeline 100+ GW. |
| Gas (CCGT) | 20-35% | 394 gCO2/kWh | Flexible, dispatchable. Dominates when wind is low. Phase-out planned by 2035. |
| Solar PV | 5-8% | 41 gCO2/kWh | Growing. Peaks midday; zero at night. Capacity factor 10-12% in UK. |
| Imports (interconnectors) | 4-8% | 150 gCO2/kWh (avg EU) | From France (nuclear-heavy), Netherlands, Belgium. Helps balance demand. |
| Biomass and other | 3-5% | 120 gCO2/kWh lifecycle | Drax (largest), smaller stations. CCC views sustainably-sourced only. |
Key trends
- 2024 reality: Grid is roughly 50% zero-carbon (nuclear + renewables) on average. Varies hour-to-hour.
- 2030 trajectory: Aiming for 80-85% zero-carbon. Requires 50+ GW offshore wind, 40+ GW solar, plus battery storage.
- 2035 legally binding: No new gas power. Existing CCGT units must close or operate only during peak demand shortfalls.
- Challenge: Wind and solar are intermittent. Need either long-term storage (green hydrogen, liquid air) or flexible demand.
Authoritative tools and data sources
We built this workspace using public data from Ofgem, the ESO, Elexon, and the Committee on Climate Change. Here are the best places to find real-time or detailed information.
Advanced tools in this workspace
Price cap and billing
Live electricity data
Policy and strategy
Consumer tools
Methodology and sources
- Energy bill calculator: Offers Ofgem average direct debit electricity cap references for 1 January to 31 March 2026 (27.69 p/kWh, 54.75 p/day) and 1 April to 30 June 2026 (24.67 p/kWh, 57.21 p/day). VAT is applied at 5% to the full domestic subtotal. Regional and supplier variation still apply in practice.
- Carbon factors: Wind and nuclear 12 gCO2/kWh (lifecycle). Solar 41 gCO2/kWh. Gas (CCGT) 394 gCO2/kWh. Biomass 120 gCO2/kWh (lifecycle, sustainable only). Imports estimated at 150 gCO2/kWh (European grid average). Source: BEIS electricity generation costs, CCC analysis.
- Generation mix: Based on ESO annual and monthly data. 2024 figures represent calendar year average. Real-time data varies hourly; check ESO data portal for current snapshot.
- No personalisation: These tools use standard assumptions. Your actual bill depends on regional network charges, supplier margin, payment method, and consumption profile. Your actual carbon emissions depend on the time of day you use electricity and your region's DNO carbon factors.