Two years ago my family bought an electric car for the commutes to work as a sustainable and clean alternative to another gas fuelled car. Since last year there are also federal subsidies for purchasing an electric car in Germany which however are largely not used by the citizens. Obviously driving the own car is a big thing in the US and so I was interested how much CO2 emission could be saved if everybody would drive an electric car instead of a gas fuelled car.
So I did some calculations which are explained in the following text.
The United States are home to the second largest passenger vehicle market in the world second now to China. Overall, there were an estimated 260 million registered passenger vehicles in the United States in 2014  which results in about 0.82 vehicles per capita. What is the average number of miles driven per year by US drivers? The short answer is: 13,476, according to the U.S. Department of Transportation Federal Highway Administration (FHWA). Those distances are driven with an average consumption of 21.4 mpg for light duty vehicles.
If we put this numbers together we come up with the following calculation:
260 million cars each drive 13,476 miles per year and hence, total 3,503 billion miles per year.Utilizing this numbers I want to estimate roughly how much gas those cars consume per year. 3,503,760,000,000 miles per year divided by 21.4 mpg shows that about 163,727 million gallons of gas are blown up into the air each year. About 19.64 pounds of carbon dioxide (CO2) are produced from burning a gallon of gasoline that does not contain ethanol. Multiplying the prior numbers the result is about 1,458 million metric tons of CO2.
Comparing this result to the data of the US Energy Information Administration reveals that we are not far away from the truth. The U.S. Energy Information Administration (EIA) estimates the U.S. motor gasoline and diesel (distillate) fuel consumption for transportation in 2015 resulted in a total of 1,545 million metric tons of CO2. According to the US Environmental Protection Agency the combustion of fossil fuels such as gasoline and diesel to transport people and goods is the second largest source of CO2 emissions, accounting for about 31 percent of total U.S. CO2 emissions. This number includes transportation sources such as highway vehicles, air travel, marine transportation, and rail.
Now I asked myself the question: How much carbon dioxide would be emitted if all vehicles would be electric cars? This question cannot be answered easily since it heavily depends on how the electricity is produced. Therefore it differs strongly between countries like India that are coal based and Iceland which gains it energy mostly from renewable energies like thermal power plants. The figure below shows how the CO2 emissions of an electric car are in various countries.
Given the 13,476 miles (21,687.5 km) for 260 million cars and 202 g CO2/km we come up with 1,139,027,500 metric tons of CO2 for the entire United States which is apparently less than the emissions of gas fuelled cars. Calculating with data of the US Department of Energy provides even more optimistic numbers. Electric cars in Washington emit 1,002 pounds of CO2 per year on average whereas the US total average is 4,816 pounds. For the US that is a total CO2 emission of 567,970,000 metric tons per year. That matches an energy saving of 63.24% compared to gas fuelled cars.
Given that numbers I think it’s reasonable to think about a federal or state subsidy for electric cars and the installation of charging stations in public parking spaces. Solar energy really became popular when the German government subsidized its installation on private roofs and guaranteed the owners a certain purchase price per kWh. Now 12 years later, solar energy is popular all over the world. What I want to tell with this example is that sometimes it needs a political nudge to expedite good things.