Are EVs really zero-emission cars?
While electric cars are considered zero-emission-at-tailpipe-vehicles, their widespread uptake will eventually cause an increase in electrical generation needs. Depending on the source of energy used to generate this electricity, EVs might be significantly or only slightly less polluting than efficient gasoline, hybrid or diesel cars. In fact, if energy is taken from renewable sources, such as solar and wind energy, EVs can truly become zero-emission vehicles. EVs are therefore one of the most promising technologies to spur the use of renewable energies and stabilise fluctuating energy supply by storing this energy in the battery overnight. An example: Based on the assumption that most electricity in the US is from fossil sources, and that half of that is from coal, accepting a 70 to 80% efficiency for the EV gives only 20% overall efficiency when recharged from fossil fuels.
