Electric transportation represents an exciting technological option for reducing energy consumption and improving the environment. But, is there such a thing as a zero emissions vehicle?

Conventional vehicles are responsible for a number of principal pollutants, including:

• Ozone – Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs), which, when mixed with sunlight, form ozone.
• Particulate Matter – a mixture of solid particles and liquid droplets often seen in the air as soot and smoke. Particulate matter includes inorganic salts, acids, metals, water, organic compounds, and soot-like material.
• Carbon Monoxide – a colorless, odorless gas, which is emitted during the combustion of gasoline, wood, natural gas, and other fuels. Motor vehicles are responsible for 60% of such emissions in the United States.
• Lead – Emitted into the air by lead battery manufacturing plants, lead battery recovery plants, smelter operations, and combustion of lead-containing coal.
• Sulfur Dioxide – a colorless, odorless gas at low concentrations, but has a pungent odor at higher concentrations. Sulfur dioxide is emitted primarily from power plants that burn sulfur-containing coal, petroleum refineries, and sulfuric acid plants.

The newest addition to UTHSC’s maintenance fleet is certainly a gem. The medical school has purchased a Global Electric Motorcar (GEM) from Daimler Chrysler. The two-person all-electric vehicle with an aluminum frame and lightweight plastic body has a range of 30 to 35 miles. No special chargers are required – the GEM plugs into a standard 110-volt household outlet and can be fully recharged in about 8 hours. Its six 12-volt deep-cycle lead-acid batteries seem to be its only environmental drawback.

With electric cars, drive systems can be powered by domestically produced energy from a diverse array of feedstocks. They have little-to-no emissions in operation, and are highly energy efficient. Once the energy is received, the electric vehicle uses it much more efficiently than a gasoline fueled vehicle, with 88% of the energy actually used to drive the car. A conventional engine wastes 85% of the energy in the gasoline as heat and noise, leaving only 15% to drive the car. Electric transportation produces no tailpipe emissions and generates insignificant, ancillary emissions during operations.

However, while electric cars themselves are clean, generating the electricity to charge vehicle batteries produces air pollution and solid waste. Electricity is produced from power plants located throughout the country, transmitted to substations through high voltage transmission systems, stepped down to lower voltage, and carried to homes and businesses through distribution systems. If electric power plants produce electricity using clean energy sources (solar, wind, geothermal, hydroelectric, tidal power), emissions are negligible.

Electric vehicles are much cleaner overall than a conventional gasoline fuel car, even when including power plant emissions. However, coal-fired power plants produce emissions such as carbon dioxide, which contributes to global warming.

Coal is the number one source of electricity produced in the U.S. (54%). Out of the entire U.S. electric industry, coal-fired power plants contribute 96% of sulfur dioxide emissions, 93% of nitrogen oxide emissions, 88% of carbon dioxide emissions, and 99% of mercury emissions. Coal-fired power plants are the single largest source of mercury pollution in the United States. According to the National Wildlife Federation, just one drop of mercury – 1/70th of a teaspoon – can contaminate a 25-acre lake to the point where fish are unsafe to eat. Not only are methylated mercury compounds toxic, but they are highly bio-accumulative as well. The increase in mercury as it rises in the aquatic food chain results in relatively high levels of mercury in fish consumed by humans.

The next biohazards to consider are toxic lead and caustic sulfuric acid used in electric car battery packs. Batteries contain gallons of acid, and have the potential to produce a tremendous amount of pollution. Many vehicle batteries contain toxic elements or produce toxic emissions, which could make battery production, transport, use, and disposal a significant solid waste issue. The United States must consider how to safely dispose of or recycle these batteries.

In some models, batteries for a single electric car require about 1,000 pounds of lead, so the proliferation of electric cars using lead-acid batteries will greatly increase demand for the noxious heavy metal. The greater the demand for lead, the greater the pollution threat from mining, smelting, transporting, using and disposing of it. However according to several studies, lead recycling in the U.S. now accounts for 93-98% of all lead batteries now manufactured.

So, the question remains “Is there such a thing as a zero emissions vehicle?” No, the fact is there really is no such thing as an absolutely “clean car” if you consider everything associated with the manufacturing and recycling of the vehicles components and power source.