The electrification of cars is happening in phases, with gradually increasing electric/combustion power capacity ratios. This benefits the adoption of the electric car, as consumers can get used to the technology and adapt in small steps.
Figure: Evolution of the Electric Car. An excellent representation published by Gary Kendall, Ph.D. in his (also excellent) report: "Plugged In; The End of The Oil Age" in 2008 by WWF.
In the first phase, hybrid electric vehicles (HEV) came into the picture, allowing people to get experience of small bits of electric driving. The Toyota Prius (1997) was the first widely available HEV, with a revolutionary mileage of ~50 mpg. The ICE is turned off when waiting for a traffic light and initial acceleration is done using the electric motor. The batteries are primarily charged by ‘regenerative braking’, which uses the electric motor as a generator (or: ‘dynamo’) while braking. Naturally, these applications boost mileage more for city driving than highway driving. Then, engine size decreased while battery size and electric motor power increased, again enhancing mileage. Some models even allow short distances of Full-Electric drive under low-load conditions like for driving in residential areas (EV-mode for Toyota Prius, 2010).
The second phase is currently in its take off phase: Plug-in Hybrid Electric Vehicles (PHEV), which for the first time allows the driver to use another energy source besides gas, namely electricity from the grid. The all-electric range is sufficient for most trips, and for extended trips the engine automatically turns on to power the electric motor when the battery is depleted. The one major drawback of a full EV’s (range) is therefore taken out of the equation, while retaining emissions- and cost benefits of full-electric driving.
Some car manufacturers have decided to leapfrog this step (Nissan and likely BMW) and started building Battery Electric Vehicles (BEV) right away. The Nissan LEAF is the first commercially available BEV after General Motors’ EV1 was terminated in 2002. The BEV can be considered the final stage of the electrification of the automotive industry. From that point on, the further environmental improvements that can be made are cleaning the electricity source (less coal, more renewables) and improving the range of the vehicles.
The use and benefits of the second and third stage configurations is subject to the user’s driving behavior and it is therefore important to investigate what users’ range requirements are for an electric vehicle of some sort. This is exactly what is done in this study. Please read more about it in the next pages:
Kendall, G., & WWF. (2008). Plugged in. Nature (Vol. 447). Brussels.