Efficiency of Electric Vehicles

The energy efficiency of electric vehicles is analysed and compared against conventional ICE vehicles.


This report was the culmination of a course on Automotive Systems, wherein I explored the various subsystems of an automobile in detail. However, only a small portion of the modern hybrid and electric drivetrains was discussed, which led me to explore these powertrains further, and I hence chose my report in the domain of electric vehicles.

Around this time, climate change and pollution were, and still, are topics in the focus of the general public. Cars are often made the scapegoat, and conventional fossil fuel based engines are often touted as the most pollutant objects in our daily lives.

After covering the efficiency achieved in conventional combustion engines, I was intrigued about just how much of an impact they have on the environment, especially compared directly to electric vehicles. I was not satisfied with the explanation that electric cars were completely harmless and that they were the clean alternative to conventional and hybrid engines.

My Contribution

I was the only one working on this report, as per the course requirements. Hence, I was responsible for deciding the topic of the small research and then conducting the actual literature review to grasp the salient features about the subject. It took me a significant amount of time to confirm my hypothesis, as most people on the internet believed in the absolute clean nature of electric vehicles. However, I was able to find sufficient backing in the relevant literature, which then led me to write the report.

The hidden costs to the environment behind the operation of an electric vehicle are not apparent at first; when we plug in the car, we do not think about the source of the electricity. There is no visible indicator of pollution as in combustion engines; this creates an incorrect inference that electric vehicles do not affect the atmosphere. What we fail to see is the hidden cost that comes from the source of electricity. As the report states, most of the power in India and other countries still comes from coal and other fossil fuel based sources, which means that the environmental cost shifts from the owner to the electricity producer.

A table comparing the efficiencies of different classes of vehicles.

The Outcome

From the above analysis, we see that the typical efficiency of an electric vehicle is around 60% and is expected to go up to about 70% soon. Corresponding efficiencies of internal combustion engine vehicles are in the range of 20% and are expected to go up to 30% in the future. Hence it may be said by advocates of EVs that electric vehicles are significantly much more efficient as compared to ICEVs, but they would be painting only a part of the whole picture. Some people refer to electric vehicles as Energy Elsewhere Vehicles, referring to the fact that the raw energy input of electric cars is not liquid oil but electricity, which has to be both generated and transmitted to the vehicle before it is used, and this can mask drastic inefficiencies. Typical electricity generation methods include fossil fuel based thermal power plants, wind farms, hydroelectric power plants, nuclear power plants and solar cells. Each of these processes has inefficiencies of their own and cause a drastic drop in the overall efficiency number of the EVs. Taking into account these losses and transmission losses, the efficiency of EVs turns out to be 23-30%, which is not significantly different from that of ICEVs. Thus it can be argued that the electric vehicles are just as efficient, if not less, than their IC counterparts. This assessment, however, would be highly erroneous, as it completely overlooks the fact that we are moving towards a future that is going to be powered by green renewable sources such as solar and wind.

Electric vehicles thus are a compelling concept in that they can use energy obtained from any means, and hence is not limited by the technology at the time of its creation as all internal combustion engines are. It is a compelling idea that the efficiency of ICEVs is limited by the technology at the time of production, whereas that of EVs can improve with time.