Electric Vehicles (Energy)
Vehicles powered by electric motors or by a combination of gasoline engines and electric motors are becoming more common, with two percent of the USA fleet being electric,. Such vehicles are useful in the slow, stop-and-go traffic of cities, but are less advantageous for high-speed, long-distance travel and hills. Battery technology limits the amount of energy that a vehicle can carry and thus its speed, range, and leads to long recharge time. Lead-acid batteries are inexpensive and reliable but are heavy and have low energy and power per size and weight. Several manufacturers of these vehicles has developed a model equipped with lithium polymer batteries that will extend its range to 100 miles (161 km), but pricing and availability have yet to be determined.
On the high end of the electric vehicle spectrum is a Tesla Roadster. For $101,500, one can purchase this electric-powered sports car that has a top speed of 125 mph, an acceleration from 0 mph to 60 mph in under 4 seconds, and a range of about 220 miles. This vehicle is equipped with 6831 lithium-ion cells, each about the size of an “AA” battery. (Berdichevsky et al, 2007) Together, the battery cells weigh 992 pounds (450 kg), have a service life that should extend 100,000 miles (161,000 km), and cost more than $30,000 retail. Recharge time is as short as 3.5 hours with a special, stationary charging unit and eight hours or longer with a mobile unit.
Electric vehicles, despite their limited range, long recharge (refueling) times, and high costs, have some advantages over other vehicle types. Electric motors often achieve up to 90% conversion efficiency (the ratio of the input of electrical energy to the output of kinetic energy in the moving vehicle), and electric vehicles themselves emit no greenhouse gases; however, fossil fuels are part of the energy mix needed to charge the electric vehicle, so that greenhouse gases are a product of electric vehicle use. The power plants that generate the electricity to charge the vehicles produce greenhouse gases, but large power plants are more efficient than small engines and may enlist carbon capture and storage technologies. Moreover, electric vehicles can recharge at night during the slack hours for electric power grids and thus, may not strain current generating capacities. Some electric vehicles even work to charge themselves through regenerative braking, in which the electric motor driving the wheels also acts as a generator, which helps stop the vehicle by converting the kinetic energy of the moving vehicle into electricity that recharges its batteries.
Energy to manufacture batteries
Battery manufacture and disposal for electric vehicle lithium batteries require large amounts of energy. This factor is to be considered in calculating the effective comparison of total fossil fuel consumed over the life cycle of an electric vehicle. For example the carbon cost of manufacturing a single Tesla Model S lithium battery is 7300 kg,(Dai et al, 2019}, rendering that electric vehicle less carbon efficient than the 2021 Prius Hybrid Electric, or even less carbon efficient than a conventional high efficiency internal combustion auto, when one considers the full carbon life cycle cost. However, as Dai notes, the 7300 kg of carbon dioxide to produce one lithium battery is underestimated due to: (a) not accounting for energy intensive manufacturing conditions of extreme dehumidification and temperature control needed where most production occurs, such as South Korea and China; and (b) not accounting for the very energy intensive transport over dirt roads for cobalt ore in Congo. Thus the carbon cost of the subject lithium ion battery is at least 8000 kg of CO2. Dai et al assert: " we conclude that the upstream production of (lithium ion) battery materials as a whole incurs more energy and environmental burdens than the cell production and pack assembly process."
Noise pollution is greatly reduced for electric vehlcles, compared to conventional gasoline or diesel engine vehicles; however, pedestrian death rates are increasing due to lesser ability of pedestrians to hear oncoming electric vehicle approach. The National Highway Traffic Safety Administration conducted a large scale twelve state study that showed electric vehicles are 35 percent more likely to cause a pedestrian fatality. The pedestrian deaths by electric vehicles are particularly high for children and seniors. Pedestrian deaths had declined steadily since 1980 had declined steadily until 2010, when electric cars were introduced; in the next nine years pedestrian deaths increased by 70.1 percent. Bicyclist deaths due to electric vehicles demonstrates an even higher percentage kill rate compared to pedestrians. Most dramatically as electric vehicle adoption accelerated in 2020, pedestrian deaths per vehicle mile increased an astonishing twenty percent.
Electric vehicles also have a certain appeal from a mechanical and engineering perspective. An electric motor provides high torque (rotational force down a shaft) over the full range of speeds, and therefore electric vehicles do not need gears, belts, or chains between the motor and the wheels. All the components in an electric vehicle operate at temperatures near room temperature. Consequently, electric vehicles require less maintenance than gasoline- or diesel-powered vehicles. Typically, only the tires and brakes need regular service.
Electric Vehicle Battery Disposal
Disposal of electric vehicle batteries is a major problem. There are presently only experimental efforts to study recycling; otherwise, most of these batteries, which have highly toxic contents end up in landfills, subject to toxic elements leaking into soils or groundwater. (Lander et al, 2021) There is an active industry in the USA and several other countries to ship this toxic waste to underdeveloped countries such as Bangladesh, where toxic disposal of electronic wastes is not regulated.
Moreover, the lack of recycling profitability is leading to an increased export of electric vehicle batteries to countries without strong hazardous waste legislation, to dispose illegally (Baars et al., 2020; Green, 2017; Skeete et al., 2020; Steward et al., 2019). It has been estimated that illegal disposal occurs for 30% of vehicles in the United Kingdom (Skeete et al., 2020). According to Winslow: "If recycling remains unprofitable, battery waste mountains could build up, which, if uncontrolled, bear a significant environmental and safety risk, as toxic chemicals could leak into the environment and landfill fires might occur" (Winslow et al., 2018). Therefore, the lack of ability to properly dispose used electric vehicle batteries creates not only an environmental impact, but an implied large carbon footprint impact, that cannot be quantified.
This is partially excerpted from the book Global Climate Change: Convergence of Disciplines by Dr. Arnold J. Bloom and taken from UCVerse of the University of California. ©2010 Sinauer Associates and UC Regents
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- Berdichevsky, G., K. Kelty, J. Straubel, and E. Toomre (2007) The Tesla Roadster Battery System, Tesla Motors, San Carlos, CA, http://www.teslamotors.com/display_data/TeslaRoadsterBatterySyst.em.pdf
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