The ever-growing share of electrical vehicles (EVs) on the automobile market has been stunning over the course of the past few years. Promoted as capable of dramatically cutting both greenhouse gas emissions and energy consumption, the EVs’ boasted ecological aspect has nevertheless raised some doubts in the minds of consumers. The question that is on everyone’s lips is: Are electric cars always greener than gasoline vehicles if we take more than mere gas consumption into account?
The Sources of Input
It would be too easy – and misleading – to claim that EVs are more ecological than internal combustion vehicles (ICVs) simply because they don’t have a gas tank. In fact, EVs are just as likely to be powered by fossil fuels (such as petroleum): the nature of their energy input depends, indeed, on the sources of electricity generation.
For instance, coal accounted for 42% of the United States’ total electricity generation in 2011. Natural gas accounted for 25%, and petroleum made up less than 1%. The rest of the country’s supply of electricity was mostly generated by nuclear and wind power.
In other words, charging the battery of an EV in the United States is not a process devoid of fossil fuels at all! In fact, they represent more than two-thirds of the sources of energy needed to generate the electricity that allows EV drivers to get on the road! One could then be tempted to simplify the equation as follows: EVs, just like ICVs, are powered by dirty stuff. Alas, that logic is highly incomplete.
First, electricity is not generated by coal, natural gas, and petroleum everywhere on earth. In fact, America’s northern neighbor – namely, Canada – has a bunch of provinces whose main sources of power generation are renewable resources. Second, there is a considerable energy efficiency gap between driving on electricity generated by a power plant using fossil fuels (such as in the USA) and driving on a gas tank.
According to an article published on the University of British Columbia’s (UBC) website, an EV spends only about one-third of the energy that an ICV uses. In effect, the calculations displayed in the article show that an EV needs to consume 0.82 MJ of energy per kilometre travelled, compared to the 2.4 MJ that an ICV necessitates.
This substantial discrepancy is mostly due to the greater efficiency of an electrical engine compared to that of an internal combustion one, which usually stands somewhere around 25%. The latter type of engine indeed wastes a lot of energy in heat losses, whereas the former generally benefits from a regenerative braking system allowing the recovery of much of the kinetic energy that is lost when the divers breaks.
The figures shown to this point nevertheless omit to take into account a broader picture of energy consumption. An academic paper recently published by a group of researchers at the Technical University of Lisbon actually does so by comparing the energy spent during an EV’s and an ICV’s entire life cycle, from their very conception to their disposal.
The results the Portuguese team obtained are actually quite in favor of EVs. Despite the fact that their material production (including the battery) and their assembly necessitate more energy, EVs consume as much as 38% less energy than ICVs over their life span. This is mostly due to the better overall efficiency of electrical systems.
Of course, these figures can vary according to some parameters such as the electricity generation mix: Portugal does not use the same energy sources as Canada or the United States to produce its electricity. However, the researchers considered different scenarios and under all of them, EVs always ended up consuming less energy throughout their life cycle than ICVs.
Greenhouse Gas Emissions
According to the Portuguese scientific team, once again, EVs do not only consume less energy than ICVs; they also emit less carbon dioxide. If effect, their results show that EVs can emit 23% less of this kind of greenhouse gas (GHG) than ICVs over the course of their life cycle.
This figure was even better for UBC’s team, as British Columbia’s electricity mostly comes from hydropower, which significantly reduces GHG emissions compared to other sources of energy. In effect, UBC’s calculations show that EVs in the western Canadian province only emit 4.4 grams of carbon dioxide per kilometre travelled, compared to a skyrocketing 176 grams for ICVs!
In the light of all this, many of the doubts consumers may have had about electric cars’ real ecological potential should be dispelled. It indeed appears that EVs beat the performance of ICVs both in terms of energy efficiency and of GHG emissions. Even though figures may vary according to the energy sources used to generate electricity in a given country, it seems that EVs always end up having an interesting comparative advantage over ICVs.
Tazzari Electric Car – Wikimedia Creative Commons
Guest Author Bio
Alexandre Duval is a blogger for Mercier Nissan, an auto dealer in Quebec. He is also currently completing his master’s degree in political science at the University of Quebec in Montreal.