|Southface Journal of Sustainable Building Volume 4, December 1997 |
Alternative Fueled Vehicles Bring a Breath of Fresh Air by Julie Simon and Kent Iglehart
Compressed natural gas MARTA bus
Atlantans drive more miles each day on average than in any other US city: 33 miles (53 km) per day per capita. The daily total reached 100 million miles (160 million km) in 1995 and continues to grow. All that driving fouls the air we breathe and contributes to the need to import growing quantities of petroleum. Although measures to increase walking, bicycling, rail, and other transportation options are urgently needed in Atlanta, people will continue to need personal motor vehicles for decades to come. Alternative fueled vehicles (AFVs), powered by electricity, natural gas, and propane can provide a more environmentally benign alternative to vehicles powered by gasoline. Alternatives to gasoline have been around for a long time. In fact, in 1900, Americans owned more electric vehicles (EVs) than gasoline-powered cars. The electric RAV4 EV1
The push for AFVs resurfaced as the 1990 Clean Air Act Amendments drastically reduced allowable emissions and mandated sales of zero-emission and other clean vehicles. Currently, more than 2,000 AFVs are being driven in the Atlanta area, including the highly visible MARTA natural gas buses, UPS natural gas delivery trucks, EVs at Perimeter Mall and Emory, and propane trucks in DeKalb County to name a few. Natural gas vehicles (NGVs) operate on the same natural gas many people have in their homes. To enable sufficient storage, natural gas is compressed to between 2,400 and 3,600 pounds per square inch (psi) in cylinders that have proven to be much safer than gasoline tanks. Due to limitations in storage capacity, NGVs have a range of 100 to 250 miles per fill. NGVs can refuel under low pressure at about a gallon an hour or, under high pressure, in time comparable to filling a gasoline tank.