The major assumption that gets thrown around is that an electric car has zero emissions. However, this is only slightly true. By itself, an electric car does not produce any gas emissions, unless the battery or vehicle catches on fire. The main question is how do you charge the batteries? Where does that energy come from? The answer is that an electric car charges from being plugged in to the nation's power grid, which means that the electricity is coming from local power plants (i.e. coal, natural gas, nuclear). Since most of the United States power grid is energized by coal and natural gas plants (~68 percent according the U.S. Energy Information Administration - EIA), your electric car will most likely be getting its power from fossil-fueled, pollution-emitting sources.
What this really means is that you are not necessarily "saving the planet" with your electric car, and, by proxy, electric cars don't eliminate emissions. Electric cars are simply 'passing the buck' to the power stations, where you get your electricity on a daily basis. You could be getting your electricity from renewable sources, but on average, more people will be getting their power from coal or natural gas sources. In the future, the U.S. could move to more environmentally friendly sources like solar, tidal, wind, hydroelectric, and/or nuclear (I am sure some people will argue against this last one). If this occurs, then CO2(carbon dioxide) emissions could be reduced dramatically. However, at this time, coal and natural gas plants will most likely be charging your vehicle. You could charge your car with solar panels, but current solar technologies are not powerful enough to charge a vehicle within a reasonable time frame. Although, there is promising research on solar cars being performed at the University of Michigan and Stanford University. Nuclear sources are currently about 19% of the overall power grid, but they are not exactly a popular topic (I will discuss this at another time). Other renewable energy sources could be used, but they are not currently being utilized in large amounts.
Therefore, it basically comes down to gasoline versus coal. To quantify which is better, I will start by looking at the overall energy density, which is the total amount of energy (in megajoules) produced from a select amount of the material (in kilograms). Gasoline has an approximate energy of 46 MJ/kg, while coal has a smaller energy density of about 24 MJ/kg. This means you have to burn almost twice as much coal to get the same amount of energy from gasoline. Natural gas (47MJ/kg) has an energy density slightly higher than gasoline, but the main point is that you are not really saving on emissions and CO2production. Uranium used for nuclear power on the other hand has an energy density of about 80,000,000 MJ/kg, which means that nuclear power provides the most energy for each gram of uranium. However, many people have questions and concerns about this source of energy.
While a gasoline engine produces more energy per kilogram, the question is about pollution and how much CO2 is produced by each process? According to the EIA, coal generates about 0.230 lbs of CO2 per MJ, while gasoline produces 0.160 lbs of CO2 per MJ. Therefore, gasoline looks to come out on top, again. However, if you consider that most oil is imported, then you have to consider the amount of diesel burned by the tanker that has to ship the oil. However, recent oil production has increased in the U.S. to such a point that the U.S. is exporting more oil than it imports. Also, if you consider that approximately 30 percent of your electricity is renewable energy, then this brings gasoline and electric vehicles back to level ground, if not giving electric a slight advantage. However, it is still not a zero emission car quite yet.
If electric cars are not zero emission vehicles, then "Why would you want an electric car?" Well, coal and natural gas is currently really cheap! According to the U.S. Department of Energy and Environmental Protection Agency's fuel economy guide, the average fuel efficiency of a vehicle is about 25 miles per gallon and that gas costs around $3.50 per gallon, the cost for a gasoline engine is about $0.14 per mile. For electric cars, it takes about 0.4 kWh per mile (1 kWh = 3.6 MJ). At an average price of $0.09 per kWh for coal, the cost for an electric engine is about $0.04 per mile. With electricity costing about 1/3 the price of gasoline for the same trip, this makes electric cars much more cost efficient, even though they may not necessarily be "green."
Another argument that could be made is that the electrical grid is local. Our electricity is not imported from foreign countries. Therefore, our electrical power is generated within the United States, which essentially makes the electricity powering your car "Made in the USA". This means that by plugging into the power grid, you are supporting local power companies and helping to provide jobs for local people. In turn, this will help the overall economy of the country and help the country become less dependent on foreign oil.
The savings in the cost of charging your electric car could be marred by the difference in price for the vehicle itself, but that depends on which electric car you get. The cost of theChevy Volt (a electric/gas hybrid) is approximately $30,000. A comparable car to the Volt is a Chevy Malibu, which costs about $20,000. Therefore, you are spending $10,000 more for 30-40 miles of electric charge. For fully electric cars, you could go with the Tesla Roadster for around $100,000, but that is not very accessible to most Americans. However, the Nissan Leaf can be as low as $20,000 and the new Chevy Spark is looking to be as low as $12,000. These vehicles are smaller, but they're prices are comparable to gasoline cars similar in size. The examples above are just a handful of electric cars that are available. Many manufacturers are working on electric vehicles. It should be noted that my choice to mention three Chevy vehicles was mainly because they have three different types (conventional gasoline, electric/gas hybrid, and fully electric) and can be compared easily without variable company related costs.
A major difference between electric and combustion engine cars is the overall maintenance and design. An electric car has about a handful of moving parts, while a combustion engine has hundreds. Therefore, in an electric car, there are not many parts that can break, and if something does wear out, then it is relatively easy to replace. The electric car essentially has a battery, motor, and some electrical components, which requirelittle to no maintenance. Since most take advantage of regenerative braking (storing energy when as you slow down), brakes don't wear as fast. An electric car doesn't typically have the combustion engine (Chevy Volt being an exception), because of this, there are fewer fluids to worry about and general maintenance is quicker and cleaner.
At this point, the electric car doesn't currently beat out a standard combustion engine in saving the environment, but it does cost less to run and can help keep the local economy running, while decreasing the dependence on foreign oil. This may not be a convincing argument for some people, but the main point of this article is to make people aware of what they are buying. While I am a big fan of electric vehicles, my goal is not to tell people to buy or not buy an electric car, but to show that there is more that we need to do as a society to improve the our overall environmental impact.
Since the electric car's ability to be "green" is directly tied to what we do as a society, we need look towards more renewable energy sources. If we generate most of our electricity with fossil fuels, then the environmental savings of electric vehicles are not going to be much. However, if the U.S. continues to smartly moving towards more renewable energy sources, then the electric car's ability to be "green" will increase over the next couple of decades. If you couple that to progresses in battery technologies and engine efficiencies, then electric cars will be both more cost efficient and environmentally friendly in the future.