How to Report Carbon Emissions for an Electric Vehicle Fleet
Electric Vehicle Fleet Carbon Reporting: What Changes and What Stays the Same
Many companies switching to electric vehicles assume their transport emissions drop to zero. They do not. The emissions shift from Scope 1 (combustion of diesel or petrol in the vehicle engine) to Scope 2 (electricity used to charge the vehicles). Depending on your grid, this can still represent significant tCO2e that must be reported.
What Changes When You Switch to EVs
Scope 1 goes down: Electric vehicles produce zero tailpipe emissions, so fuel combustion emissions (diesel: 2.68 kgCO2e/litre, petrol: 2.31 kgCO2e/litre) disappear from your Scope 1 once you retire the combustion fleet.
Scope 2 goes up: Electricity used to charge EVs is a Scope 2 emission. You need to account for the kWh consumed by the fleet and apply your country's grid factor.
How to Calculate Scope 2 from EV Charging
The most accurate method uses actual kWh consumed, which you can get from:
- Smart charger data logs (most business-grade chargers provide kWh per session)
- Fleet management software (telematics systems often report energy consumption)
- Vehicle OBD data (miles driven divided by published kWh/mile efficiency)
Approximate EV consumption rates: - Small van (e.g. Renault Kangoo E-Tech): 0.25 kWh/km - Medium van (e.g. Volkswagen ID. Buzz): 0.30 kWh/km - Large van (e.g. Mercedes eSprinter): 0.38 kWh/km
Example: 10 medium vans each driving 30,000 km/year in Germany (0.380 kgCO2e/kWh): - 10 x 30,000 km x 0.30 kWh/km = 90,000 kWh - 90,000 x 0.380 = 34.2 tCO2e Scope 2
Compare to diesel: 10 vans x 30,000 km at 0.12 litres/km = 36,000 litres x 2.68 = 96.5 tCO2e Scope 1. The EVs reduce transport emissions by about 65% in Germany — but they do not eliminate them.
Charging at Home vs. Depot
If drivers charge at home overnight, the electricity is purchased by the employee, not the company. This shifts the emissions to employee-owned consumption, which falls outside your organisational boundary in most GHG Protocol interpretations. However, if you reimburse employees for home charging, many frameworks expect you to report it under Scope 3 Category 7 (employee commuting energy).
Depot charging (company-owned chargers) always falls within your Scope 2 boundary.
Well-to-Wheel vs. Tank-to-Wheel
Some questionnaires ask for well-to-wheel emissions, which includes the upstream extraction and transmission losses for the electricity (not just the generation factor). DEFRA 2023 provides transmission and distribution loss factors that can be added to the generation factor. For most questionnaires, the standard generation factor is sufficient.
Using DeCarbonOPS With an EV Fleet
DeCarbonOPS handles mixed fleets. Enter zero for diesel and petrol consumption for vehicles retired from your fleet, and include EV electricity consumption within your total kWh figure in the electricity section. The calculator applies your country-specific grid factor to produce a correct Scope 2 figure that includes both office and transport electricity. Your Carbon Passport will show the combined Scope 2 correctly.
Frequently Asked Questions
Do electric vehicles have zero Scope 1 emissions?
Yes — Scope 1 covers emissions from fuel combustion in vehicles you own or control. Electric vehicles have no tailpipe combustion, so they contribute zero to Scope 1. However, the electricity used to charge them is a Scope 2 emission. Transitioning from diesel to electric reduces total transport emissions but does not eliminate them unless you also use 100% renewable electricity.
How do I calculate kWh consumed by my EV fleet if I don't have charger data?
Use vehicle mileage and published energy consumption rates. Typical rates: small EV van 0.20–0.25 kWh/km, medium van 0.28–0.32 kWh/km, large van 0.35–0.40 kWh/km, car 0.15–0.22 kWh/km. Multiply annual km per vehicle by the consumption rate to get annual kWh. For example: 3 medium vans x 25,000 km/year x 0.30 kWh/km = 22,500 kWh/year. Apply your country's grid factor to convert to tCO2e.
Should I include home charging by employees in my Scope 2?
If employees charge company EVs at home and you reimburse them for electricity, include it in Scope 2 (or Scope 3 Category 7, depending on your boundary definition). If you do not reimburse and have no data on home charging, it falls outside your organisational boundary. Fleet vehicles charged at company depots should always be included in Scope 2.
How does buying renewable electricity certificates for EV charging affect my Scope 2?
If you purchase REGOs (UK) or GOs (EU) for the electricity used to charge your EVs — or if you have a certified renewable tariff on your depot chargers — you can apply a lower market-based Scope 2 factor (potentially zero) for the charging portion. You must still report the location-based figure alongside. This is one of the most cost-effective ways for a fleet operator to reduce their reported Scope 2.
What about hybrid vehicles — petrol-electric or diesel-electric?
Plug-in hybrid vehicles (PHEVs) have both a Scope 1 element (combustion when running on petrol or diesel) and a Scope 2 element (battery charging). Split the reporting: record fuel consumption (litres) for Scope 1, and electricity consumption (kWh) for Scope 2. Mild hybrids that do not plug in are treated as petrol or diesel vehicles — their small regenerative efficiency improvement is not typically broken out separately.
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