All-electric vehicles (EVs) run on electricity only. They are propelled by one or more electric motors powered by rechargeable battery packs. EVs have several advantages over conventional vehicles:
- Energy efficient. EVs convert about 59%–62% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 17%–21% of the energy stored in gasoline to power at the wheels.*
- Environmentally friendly. EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-, solar-, or wind-powered plants causes no air pollutants.
- Performance benefits. Electric motors provide quiet, smooth operation and stronger acceleration and require less maintenance than internal combustion engines (ICEs).
- Reduced energy dependence. Electricity is a domestic energy source.
EVs have some drawbacks compared to gasoline vehicles:
- Driving range. Range is typically limited to 60 to 120 miles on a full charge although a few models can go 200 to 300 miles.
- Recharge time. Fully recharging the battery pack can take 4 to 8 hours. Even a "fast charge" to 80% capacity can take 30 min.
Batteries for EVs are designed for extended life, and a study by DOE's National Renewable Energy Laboratory suggest these batteries may last 12 to 15 years in moderate climates and 8 to 12 years in severe climates. However, these batteries are expensive, and replacing them may be costly if they fail.
EV energy use estimated by ORNL as follows:
- Electric motor efficiency—including inverter and gear reduction losses—assumed to be 76.4%–80.2%, using estimates from Miller et. al. (SAE 2011-01-0887) and adjusting downward by 4% for parasitic losses.
- Battery and charger efficiency are assumed to total 81% (roughly 90% each) based in part on estimates from published studies (Chae et. al., 2011; Gautam et. al., 2011).