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An electric car starts 4.1 tonnes behind. When does it catch up?
Building an EV emits more than building a petrol car, almost entirely because of the battery. It then emits less to drive. This works out where those two lines cross — for your grid, your mileage, and your assumptions.
0.274 kgCO₂e per kWh, generation through to well-to-tank
Compare against
The starting position
- Petrol car, manufacturing
- 3.70 t
- EV, manufacturing
- 3.30 t
- EV, battery
- 4.50 t
- EV starts behind by
- 4.10 t
Over 8 years · 59,200 miles
The EV saves 12.74 tCO₂e over that period — 50% lower than the petrol car, manufacturing included.
Per mile, in use
- Petrol — tailpipe
- 0.287 kg
- Petrol — well-to-tank
- 0.080 kg
- Electric — grid, all scopes
- 0.082 kg
- Saved per mile
- 0.284 kg
Method & sources
What is counted
Manufacturing for both vehicles, the battery separately, and every mile driven. Fuel includes combustion at the tailpipe plus the emissions of extracting and refining it. Electricity includes generation, transmission and distribution losses, and the well-to-tank emissions of both — not just the grid figure, which would understate it by around a third.
What is not
Servicing, tyres, brake and road particulates, and end-of-life treatment. Battery second life and recycling are excluded, which is conservative: both would move the result in the EV’s favour. Vehicles are the dataset’s “medium car” class throughout.
Factors
UK Government (DEFRA) 2023 conversion factors for fuel and electricity, and IEA lifecycle assessment figures for manufacturing. Grid factors are location-based; a renewable tariff is a market-based claim and does not change the physical electricity a car draws.
The honest caveat
Grid factors are a snapshot. Most electricity systems are decarbonising, so an EV bought today gets cleaner every year it is driven, while a combustion car does not. This model holds the grid constant, which understates the EV case over a long ownership period.