Assumptions and method
- Vehicles. Litres of diesel = miles ÷ mpg × 4.546 (litres per UK gallon). EV electricity = miles ÷ miles per kWh. Charging price should be your blend of depot, home and public charging; public rapid charging is typically far more expensive than depot charging. Charging losses are assumed to be included in your miles/kWh figure.
- Heating. Useful heat = gas used × boiler efficiency. Heat pump electricity = useful heat ÷ SCOP. Assumes the heat pump meets the full load and building heat demand is unchanged.
- Efficiency. kWh saved = electricity use × saving %. Savings from electrified vehicles and heat are not netted against the efficiency saving.
- Carbon factors. Defaults are rounded approximations of recent UK government conversion factors for grid electricity, natural gas and diesel. Grid electricity carbon intensity varies by year and hour and has been falling; update these from the latest government conversion factors for reporting.
- Prices. Example prices are placeholders, not market data. Use the unit rates on your own bills (excluding standing charges) for meaningful results.
- "% of modelled footprint" compares the reduction with the emissions from only the diesel, gas and electricity entered here, not your organisation's total footprint.