Impact of Electric Cars on Global Greenhouse Gas Emissions
Electric cars are a topic of significant interest because of their role in the low carbon energy transition. In this article, I will discuss the current impact of electric cars on global fuel and electricity use and greenhouse gas emission reductions. I will also discuss the maximum possible impact of electric vehicles on global greenhouse gas emissions.
Note: The term “cars” refers to the light duty vehicles category which include cars of all sizes, sport utility vehicles, crossovers, light trucks, and minivans. Here, electric cars include battery electric cars and plug-in hybrids.
Electric cars sales and global share
The sales of electric cars have markedly increased in recent years, driven by the large subsidies from the global governments. The global subsidies in the year 2022 alone (through direct purchase incentives) were 40 billion dollars¹.
The International Energy Agency (IEA) frequently provides an update on the sales²𝄒³. The sales of electric cars have increased from less than 1 million cars in 2017 to 10 million in 2022. IEA estimates the sales of the electric cars to be 14 million in 2023.
The current share of electric cars in the global car fleet is roughly 3%⁴. More than half of the electric cars on the road are currently in China⁵.
Current impact of electric cars
IEA reported that the fleet of electric cars reduced the use of global oil by 0.5 million barrels per day in 2022⁶. For reference, the current global oil use is 100 million barrels per day⁷.
What about the impact on electricity use? IEA reports that the global electric car fleet consumed 70 TWh of electricity in 2022.
What does this mean in terms of greenhouse gas reduction?
In 2022, the global fleet of electric cars reduced the greenhouse gas emissions by 68 million tons because of the avoided oil use⁸. On the other hand, the global fleet increased the emissions by 35 million tons because of the additional use of electricity⁹. On a net basis, the global fleet of electric vehicles reduced the global greenhouse gas emissions by 33 million tons¹⁰.
The annual global greenhouse gas emissions were roughly 54 billion tons in 2022¹¹. So, the global fleet of electric cars decreased the greenhouse gas emissions by less than 0.1% in 2022. If we include the fleet of electric cars that are estimated to be added in 2023, the percent reduction will increase to 0.1%¹².
How much is 0.1% reduction in greenhouse gas emissions? We can achieve the same reduction by replacing 0.4% of the global coal power with low carbon power¹³.
Maximum (potential) impact of electric cars
The transportation sector contributes to 16% of the greenhouse gas emissions¹⁴𝄒¹⁵. Cars are a part of this sector. The cars subsector contributes to roughly 7% of the emissions¹⁶.
This informs us that electric cars at a maximum can reduce the global greenhouse gas emissions by 7%. This maximum is only possible if the conventional cars are replaced by electric cars that all use low carbon electricity.
That is not the case today. Most countries do not use low carbon electricity¹⁷. Some countries such as Norway and France do. But countries such as China and India use high carbon electricity. Others such as the United States and Germany are in the middle. According to IEA, electric cars emit 50% fewer greenhouse gases compared to conventional cars when considering the global average carbon intensity¹⁸𝄒¹⁹. This means that electric cars can reduce greenhouse gas emissions by 50% from the global cars sector.
We can use the above information to estimate the total emission reduction for an overnight switch to 100% electric cars. The global greenhouse gas emissions would reduce by 3.5% if we could magically manage an overnight switch today²⁰.
Final Remarks
The current fleet of electric cars has a low impact on greenhouse gas emissions. The impact will grow as the share of electric cars increase and the global grids achieve low carbon intensity. Other options are also available to reduce greenhouse gas emissions from the cars sector. Examples are hybrid cars (intermediate term option) and a major expansion of mass transit. I will compare and contrast these options in a later article.
Note: This is a modified excerpt from my book “The Climate Misinformation Crisis: How to move past the mistruths to a smarter energy future.
References & Notes
[1] IEA Global EV Outlook (2023). Investment. https://www.iea.org/reports/electric-vehicles Subsidies for electric cars in the year 2022 alone were roughly $40 billion. These subsidies only include direct purchase incentives. About 10 million cars were sold in 2022. So, average direct purchase subsidy per electric car sold was $4000. The subsidies represented 10% of the total spending. In the prior years from 2017 to 2022, the subsidies were 20% of the total spending.
[2] IEA Electric Vehicles (2023). Overview. https://www.iea.org/reports/electric-vehicles
[3] IEA Global EV outlook 2023. Trends in electric light-duty vehicles. https://www.iea.org/reports/global-ev-outlook-2023/trends-in-electric-light-duty-vehicles
[4] International organization of motor vehicle operators. Vehicles in use. https://www.oica.net/category/vehicles-in-use/ There were about 1.2 billion cars in use in 2020. Using a historical 4% increase in vehicles per year, the total number of global cars in use is estimated to be 1.3 billion in 2022. The number of electric cars in use in 2022 were 26 million. The number of electric cars in use is estimated to be (26 +14) 40 million in 2023.
[5] IEA Global EV outlook 2023. Trends in electric light-duty vehicles. https://www.iea.org/reports/global-ev-outlook-2023/trends-in-electric-light-duty-vehicles
[6] IEA Electric Vehicles (2023). Tracking Report. Energy subsection. Electric vehicles avoid oil consumption. https://www.iea.org/reports/electric-vehicles
[7] U.S. EIA (2023). Global Oil markets. https://www.eia.gov/outlooks/steo/report/global_oil.php
[8] 1 gallon gasoline releases 8887 grams of greenhouse gases (GHG). https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle.
[9] The average carbon intensity of electrical grid was 494 grams of GHG (CO2 equivalent) per kWh in 2022. https://ember-climate.org/data/data-tools/data-explorer/ This was used to estimate the GHG produced from the 70 TWh electricity consumed by the electric cars.
[10] This does not include the electricity consumed during vehicle manufacturing. Electric cars emit more GHGs in their manufacturing process compared to conventional cars. So, the total net GHG reduction by electric cars will be lower than that discussed in the text.
[11] EDGAR: GHG emissions of all world countries. https://edgar.jrc.ec.europa.eu/report_2023
[12] According to IEA (https://www.iea.org/reports/electric-vehicles) the electric car sales in 2023 are estimated to be 14 million. This would increase the global fleet of electric cars from 26 million to 40 million. This number can be used to estimate the net GHG reduction for the year 2023 based on data from the previous year.
[13] Relative to coal power, low carbon power emits 95% lower GHG emissions per kWh of electricity generated. The global coal power plants emit 10.5 billion tons of GHG per year. https://www.iea.org/reports/global-energy-review-CO2-emissions-in-2021-2. This means that replacing 0.4% coal power with low carbon power will reduce GHG emisions by 40 (10500*0.004*0.95) million tons per year. From the text, the impact of electric vehicles is a net yearly reduction of 37 million tons.
[14] Climate Watch: Historical GHG emissions. https://www.climatewatchdata.org/ghg-emissions?breakBy=regions&end_year=2018&gases=ch4®ions=WORLD%2CWORLD§ors=electricity-heat&start_year=1990
[15] World Resources Institute: Sector by sector. Where do global greenhouse gas emissions come from? https://ourworldindata.org/ghg-emissions-by-sector
[16] IEA. Global CO2 emission from Transport by sub-sector: 2000 to 2030. https://www.iea.org/data-and-statistics/charts/global-CO2-emissions-from-transport-by-subsector-2000-2030
[17] EMBER-climate Electricity data. World average is 494 gCO2/kWh. https://ember-climate.org/data/data-tools/data-explorer/ For reference, the carbon intensity of a low carbon power grid is less than 100 gCO2 per kWh.
[18] IEA: Comparative life cycle GHG emissions from a midsize BEV and ICE vehicle. https://www.iea.org/data-and-statistics/charts/comparative-life-cycle-greenhouse-gas-emissions-of-a-mid-size-bev-and-ice-vehicle Electric cars emit 50% fewer greenhouse gases compared to conventional cars when considering global average carbon intensity. More than half of the cars on the road are in China. The average carbon intensity of the grid in China is 438 gCO2/kWh
[19] The 50% reduction is too optimistic based on recent studies. Prior studies used the average carbon intensity of the grid. Of more relevance is the carbon intensity of the marginal electricity being used by electric cars. The marginal electricity is typically provided by coal power or natural gas. So, the carbon intensity of the marginal electricity is higher. This translates to a much lower benefit from electric cars. https://www.pnas.org/doi/abs/10.1073/pnas.2116632119
[20] The global fleet of conventional cars contributes to 7% of the total greenhouse gases. Replacing all conventional cars with electric cars that do not emit any greenhouse gases will reduce the global greenhouse gases by 7%. Replacing conventional cars with electric cars that emit 50% less greenhouse gases will reduce greenhouse gases by 3.5% very year. Countries will continue to lower the emissions from electricity. What if we consider the emissions over the life of the vehicle? It will not make a notable difference. This is because the decrease in the carbon intensity of electricity will be gradual. Also, the 50% reduction is too optimistic based on recent findings. Prior studies including the IEA study used the average carbon intensity of the grid for the estimations. The carbon intensity of the marginal electricity being used by electric cars is more relevant. The marginal electricity is typically provided by coal or natural gas. So, the carbon intensity of the marginal electricity is significantly higher. This translates to a lower benefit from electric cars. https://www.pnas.org/doi/abs/10.1073/pnas.2116632119
