As we celebrate Earth Day on April 22nd, it’s crucial to reflect on our environmental impact, especially in terms of transportation. Vehicles powered by internal combustion engines (ICE) are significant contributors to carbon emissions, but determining the sustainability of electric vehicles (EVs) compared to ICE cars, considering that electricity is mostly produced by burning fossil fuels, becomes crucial. Let’s delve into the details of this topic with the aid of real-world numbers.

According to the U.S. Energy Information Administration (EIA), the average emissions from burning fossil fuels to generate electricity are around 0.45 kg of CO₂ per kWh.

Now, let’s compare the fuel efficiency of an ICE vehicle with an EV. Using data from Spritmonitor, it is possible to determine that petrol cars have an average fuel efficiency of around 7.92 miles per litre, while diesel cars have around 9.42 miles per litre. By selecting a value in between the two, it is possible to determine the average fuel efficiency of an ICE vehicle is approximately 8.67 miles per litre. On the other hand, EVs have an average efficiency of 3.3 miles per kWh, equivalent to 29.04 miles per litre.

Now, let’s put these numbers into perspective for carbon emissions. According to the latest data, the average UK driver travels around 7,000 miles a year.

For ICE vehicles:
7000 miles / 8.7 miles per litre = 804.59 litres of fuel used annually.

For EVs:
7000 miles / 3.3 miles per kWh = 2121.21 kWh consumed annually.

Using the UK Department for Environment, Food & Rural Affairs (DEFRA) emissions data, it can be found that burning one litre of petrol or diesel emits around 2.4 kg of CO₂. The carbon emissions for an ICE vehicle compared to an EV can be derived as follows:

ICE vehicle: 804.59 litres * 2.4 kg CO₂ per litre = 1931.03 kg of CO₂ emitted annually.
EV: 2121.21 kWh * 0.45 kg CO₂/kWh = 954.54 kg of CO₂ emitted annually.

From these numbers, it’s evident that even if all the electricity used by EVs were produced from fossil fuels, the emissions would still be lower than those of ICE vehicles by 976.49 kg of CO₂ per year per vehicle. However, it’s important to note that not all electricity is produced using fossil fuels. Renewable energy sources like solar, wind, and hydroelectric power make up a significant portion of many countries’ electricity grids.

Beyond just carbon emissions, there’s another crucial aspect to consider: air quality. ICE vehicles emit pollutants like nitrogen oxides (NO_x) and particulate matter (PM), contributing to poor air quality, especially in urban areas.
While ICE vehicles emit these pollutants directly into the local environment, power plants are often located away from densely populated areas. This means that even if the electricity for EVs comes from fossil fuels, the emissions are more centralised, leading to better air quality in urban centres.

By transitioning to electric vehicles and simultaneously increasing the share of renewable energy in the grid, we can drastically reduce carbon emissions from transportation while also improving local air quality. This Earth Day, let’s celebrate the potential of EVs to drive us towards a cleaner, greener future.

References:

[1] US EIA (2024), https://www.eia.gov/
[2] Spritmonitor (2024),  https://www.spritmonitor.de/
[3] DEFRA (2007), Guidelines to Defra’s GHG conversion factors for company reporting, www.defra.gov.uk