In the last post, I looked at why an electric vehicle might be expected to have lower GHG emissions than a gasoline vehicle. In this post, I will look at what some studies have actually found. My original post on this subject was in 2015, and it can be found here.

Figure 1. Source: European Environment Agency, 2018.

A report published by the European Environment Agency looked at electric vehicles in Europe. This report concluded that the answer depended on the energy mix in the grid. As shown in Figure 1, an electric vehicle (BEV = Battery Electric Vehicle, specifically a Nissan Leaf) drawing electricity generated by burning coal caused the most GHG emissions of all. But Europe has a significant amount of clean energy in its grid. If that same Nissan Leaf consumed electricity that matched the average European mix, then it would have emissions about 40% less. Compared to a standard internal combustion vehicle burning gasoline, the electric vehicle would have 26-30% fewer lifetime emissions.

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Figure 2. Source: Nealer, Reichmuth, and Anair, 2015.

The Union of Concerned Scientists published an analysis in 2015, almost as long ago as my original post on the subject. They focused on a “well-to-wheels” analysis. This looks at the GHGs emitted by the fuel consumed to operate the vehicle, including the GHGs emitted to obtain and produce the fuel. But it does not look at GHGs emitted to manufacture or dispose of the vehicle itself.

The study used an unusual metric for its comparison: the number of miles per gallon (MPG) that a gasoline vehicle would have to achieve in order to have emissions as low as those of an electric vehicle. Using this rather unintuitive metric, the higher the MPG a gasoline vehicle would have to achieve, the more of an advantage the electric vehicle had. Like the previous report, this study also found that the answer depended on the energy mix in the grid (see Figure 2). Where there is a lot of clean electricity in the grid, a gasoline vehicle would have to achieve up to 135 MPG to reduce its emissions to those of an electric vehicle. However, where there is mostly coal-generated electricity on the grid, a gasoline vehicle would only have to achieve 35 MPG. In 2016, the average fuel efficiency of a passenger car (SUVs and pickup trucks not included) was 37.7 MPG. (Source: Bureau of Transportation Statistics.)

Figure 3. Sourse: Nealer, Reichmuth, and Anair, 2015.

As Figure 3 shows, the study found that, assuming the average energy mix on the U.S. grid in 2015, battery electric vehicles would emit 51-53% less GHG to build and operate.

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Figure 4: Lifetime GHG Emissions of Two Types of Car. Source: Kukrega, 2018.

A study published by the City of Vancouver compared the lifetime emissions per kilometer driven of a Ford Focus (gasoline vehicle) and a Mitsubishi i-MiEV (battery electric vehicle). The findings were presented as grams of GHG emitted per kilometer driven. As Figure 4 shows, The study found that the Ford emitted almost 400 grams of CO2e per kilometer, while the i-MiEV emitted slightly more than 200 – a 48% reduction. Now, the study was for British Columbia, and BC has a lot of clean energy in its grid.

These sources all agree: whether an electric vehicle reduces GHG emissions depends on the mix of energy that is in the electrical grid. This is the same conclusion I found when I looked at this question 4 years ago – the situation has not changed.

Figure 5. Source: Energy Information Administration.

Unfortunately, neither has the situation here in Missouri. As Figure 5 shows, we still have a grid that generates the vast majority of its electricity by burning coal. If GHG emissions are what you care about, then driving an electric vehicle here makes no sense. In other parts of the country, however, it might make a great deal of sense.

Sources

Bureau of Transportation Statistics. 2016. Average Fuel Efficiency of U.S. Light Duty Vehicles. Downloaded 9/3/2019 from https://www.bts.gov/content/average-fuel-efficiency-us-light-duty-vehicles.

Department of Energy. 2019a. Emissions from Hybrid and Plug-In Electric Vehicles. Downloaded 9/2/2019 from https://afdc.energy.gov/vehicles/electric_emissions.html.

Department of Energy. 2019b. “Find and Compare Cars.” www.fueleconomy.gov. Viewed online 9/2/2019 at https://www.fueleconomy.gov/feg/findacar.shtm.

U.S. Energy Information Administration. 2019. Missouri State Energy Profile. Downloaded 90302019 from https://www.eia.gov/state/?sid=MO#tabs-4.

European Environment Agency. 2018. Electric Vehicles from Life Cycle and Circular Economy Perspectives. Downloaded 9/2/2019 from https://www.eea.europa.eu/publications/electric-vehicles-from-life-cycle/electric-vehicles-from-life-cycle/viewfile#pdfjs.action=download.

Kukreja, Balpreet. 2018. Life Cycle Analysis of Electric Vehicles. City of Vancouver. Downloaded 9/3/2019 from https://sustain.ubc.ca/sites/sustain.ubc.ca/files/GCS/2018_GCS/Reports/2018-63%20Lifecycle%20Analysis%20of%20Electric%20Vehicles_Kukreja.pdf.

Nealer, Rachael, David Reichmuth, and Don Anair. 2015 Cleaner Cars from Cradle to Grave. Union of Concerned Scientists. Downloaded 9/2/2012 from https://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf.