There are a lot of misconceptions whizzing around the world of vehicular transportation— particularly when it comes to electric vehicles. Many online articles have denounced Tesla cars (and similar electric vehicles) as significant polluters that are just as bad, if not worse, for the environment then regular old combustion engines (gas and diesel vehicles). Whether these articles, which sometimes look more like they belong to a smear campaign than a scientific magazine, realize it or not, this is actually a very complicated question. So what is the footprint of an electric vehicle? How green is a Tesla?
First, it is important to recognize the many components of a car’s “environmental footprint.” Among the many are the car’s manufacturing process— that is what and how materials are gathered and how they are turned into a car. Additionally, the principle energy source must be considered— that is what natural processes actually make the car move (gas in the combustion engine and some type of generated electricity for electric vehicles). Finally, we might also consider the energy efficiency of the vehicle— that is how much of the energy that is stored (in the tank or battery) is actually transferred to work. We can quantify (put a number value on) the energy efficiency, in how many total joules (which is a measure of energy for both gas and electric batteries) is needed to drive a single mile. These three factors are by no means an exhaustive list, but are a good starting point to thinking about your car’s environmental impact. The manufacturing process is complicated and varying and will not be discussed here.
Starting with energy efficiency, it has been demonstrated through many studies that electric vehicles (EV) are more efficient than conventional gas vehicles, particularly through a measure of miles per gallon equivalent. This means that for every unit of energy you put in your EV, it will drive you further than if you put that same unit of energy into a gas car. This has to do with the incredible efficiency of the electric drive components as well as the inefficiency of the combustion engine. Just think, when you feel the warm hood of your car, this is excess heat energy from your engine that is not doing anything to move your car forward. In other words, this is lost energy! From thinking about the energy efficiency of vehicles, we arrive at an important conclusion: electric vehicles are more efficient at converting energy into usable work, and so switching to an electric car would mean less energy used overall!
Aside from energy efficiency, we can also think about what type of energy the car uses. A typical gas car uses a combustion engine to supply its power. That is, fuel is burned inside the car and this process produces power and heat, along with pollution, which the car emits. An electric car is a little different, for its energy is stored in the form of a large battery that provides power directly to the motor. But this isn’t the full story: where did the energy in the battery come from? More specifically, how was the electricity generated what was used to charge the battery? The answer may vary.
If an EV is in the West Chester Area, then is it likely that the electricity that charged the EV battery is from a blend of natural gas, nuclear power, and coal power. So this means that an EV might in fact be powered by fossil fuels, albeit indirectly. In other words, just having a battery powered device does not necessarily make it green— it matters where the energy in the battery came from. This highlights a key conclusion that is important to the future of electric vehicles: transitioning to renewable energy is a key component to completing the cycle of renewable energy. Think about it this way: if the owner of an EV has a solar panel, then they will drive purely on the power of the sun, emissions free. This is quite different from an EV that is charged via a coal power plant that gives off many metric tons of emissions annually. It further underscores the importance of transitioning our grid to renewable energy, so that we can make everything with a battery a little cleaner.
Key Points:
Electric vehicles are more efficient than gas cars in turning the same amount of energy into miles driven. In this way, by adopting EVs, West Chester will reduce the amount of energy that is used in its transportation sector.
The energy that powers electric vehicles (and all batteries) matters. This is why “Electrify,” the second step in West Chester’s renewable energy plan, relies on the third step, “Transition,” to complete the circle of sustainable energy generation. Otherwise our electric powered devices are indirectly powered by fossil fuels.
Article written by Eric West, Undergraduate at Cornell University
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