You may have heard the claim ‘EVs are responsible for higher lifetime emissions due to their large production footprint’. This myth was based off the fact that EV batteries are extremely carbon intensive to produce. Once you crunch the emission numbers for production and driving, a very different story emerges.
To account for full lifecycle emissions of a car, you need to look at:
- Production emissions (all carbon emissions associated with the mining of materials and production of the car)
- Driving emissions (the associated carbon emissions from the fuel type: petrol or electricity)
- End-of-life emissions (all carbon emissions associated with recycling and disposing of the car)
End-of-life emissions for both electric and internal combustion engine (ICE) vehicles are similar in size and very low compared to usage and production emissions . We will only be looking at the differences in EV and ICE production and driving emissions.
Due to the diversity of car types and sizes, there are a range of estimates for the production emissions of cars. Low estimates start at 2 metric tonnes of CO2  per car, with the highest estimate at about 17 metric tonnes . Excluding their batteries for a moment, EVs have a slightly lower production carbon footprint than ICE cars. This is due to their simplified and more efficient design. In this comparison, we will assume an average production footprint of 12 tonnes for ICE cars and 10 tonnes for EVs plus their battery.
EV batteries account for 15-70% more production emissions depending on how large the battery is . In this comparison, we will compare a standard EV battery (30kWh) and a long-range EV battery (100kWh). The standard battery produces an extra 3 tonnes while the long-range battery produces an extra 10 tonnes of production emissions . Adding the car and battery production emissions, EVs do in fact incur a significantly greater carbon footprint compared to ICE cars. How will the driving emissions compare?
Exhaust emissions of ICE cars contribute to the vast majority of a car’s carbon footprint. But how long will it take for an ICE car to offset its lower production emissions? There’s a simple way to calculate this!
By adding the production and annual driving emissions by time (T) for ICE cars, and comparing it to the production and annual driving emissions by T for EVs, you can solve for T to find the number of years it takes for ICE cars to produce greater overall emissions.
To make it harder for EVs, we will give ICE cars the benefit of the doubt and assume that the EVs are charged on a grid powered entirely by natural gas (ignoring the 20% and increasing contribution of carbon free electricity) . For the 30kWh EV, this gives us an equation of:
Solving for T gives us 0.94 years. This means the standard-range EV will compensate for its production emissions within a single year! If the car’s battery ever needs to be replaced, the emissions of the second battery are offset within an extra 3 months. Considering the average car lasts 10-20 years, these upfront emissions are more than paid off over its lifetime. It is a similar story for the long-range EV, which takes 2.5 years to break even with ICE cars (or 5.5 years with a battery replacement).
The full impact that EVs have on reducing emissions can be better shown when comparing a full lifetime’s worth of emissions. We will assume an average lifespan of 20 years for each car. To give ICE cars the benefit of the doubt, we will not factor in maintenance such as engine replacements and the EVs will have a battery replacement. Crunching these numbers results in the standard EV producing less than 50% and the long-range EV producing only 60% of the lifetime emissions of an average ICE car. This result is confirmed by the studies listed below. These numbers become more and more favourable when you consider the increasing contribution of clean energy supplying our energy grid.
Of course, some regions are powered predominantly by coal, resulting in EVs breaking even in lifetime emissions. However, they still have the benefit of removing pollution from urban centres and confining it to the power plants where emissions scrubbing technology can be installed. Rest assured, if you’re in the market for a new car, buying an electric vehicle will likely be cheaper, more convenient, and a whole lot better for the environment.
 Environmental life cycle assessment of cars, 2012, Yale University. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1530-9290.2012.00532.x
 Life cycle analysis of new cars, 2000, MIT. http://energy.mit.edu/publication/on-the-road-in-2020-a-life-cycle-analysis-of-new-automobile-technologies/
 Back-of-the-envelope calculation of a carbon footprints of cars, 2010, The Guardian. https://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car
 Cleaner cars from cradle to grave, 2015, Union for Concerned Scientists. https://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf
 Life cycle energy consumption and emissions from li-ion batteries, 2017, Swedish Environment institute. https://www.ivl.se/download/18.5922281715bdaebede9559/1496046218976/C243+The+life+cycle+energy+consumption+and+CO2+emissions+from+lithium+ion+batteries+.pdf
 Australian emissions by sector, 2018. http://www.environment.gov.au/climate-change/climate-science-data/greenhouse-gas-measurement/publications/national-greenhouse-accounts-factors-july-2018