A natural gas vehicle or NGV is an alternative fuel vehicle that uses compressed natural gas (CNG) or liquefied natural gas (LNG) as a clean alternative to other fossil fuels. Worldwide, there were 14.8 million natural gas vehicles by 2011, led by Iran with 2.86 million, Pakistan (2.85 million), Argentina (2.07 million), and Brazil (1.70 million).
Honda Motor Co. is the only automaker selling cars with compressed natural-gas engines to retail customers in the U.S. with its $26,155 Civic Natural Gas sedan. The model, formerly the Civic GX, has sold mainly in California and a small number of other U.S. states that have fueling facilities.
The “chicken and egg” problem: vehicle users will not buy NGVs until they believe there are enough refueling stations, but there is little motivation to build an NGV refueling infrastructure until a sufficient number of vehicle owners demand the fuel. There are also concerns about cruising range and cabin space of light-duty vehicles.
The biggest hurdle to wider use is refueling. Today there are fewer than 400 public CNG fueling stations in the U.S. The interest in natural-gas vehicles comes as gasoline prices are on the rise again and support for using domestic natural gas to replace oil is gaining support.
Drivers who fill up with natural gas at the pump saved up to $2 per gallon when gasoline prices hit $4 a gallon.
Car makers, manufacturers and fleet owners are quietly scrambling to run their engines on the cleaner-burning fossil fuel which was formerly the preserve of trash trucks and city buses.
Some impurities are contained in all natural gas. These include sulphur and butane and other chemicals. When burned, those impurities can create air pollution. The amount of pollution from natural gas is less than burning a more "complex" fuel like gasoline. Natural gas-powered cars are more than 90 percent cleaner than a gasoline-powered car.
"We have a supply of natural gas that can last America nearly 100 years," Mr. Obama said in his speech. "My administration will take every possible action to safely develop this energy. Experts believe this will support more than 600,000 jobs by the end of the decade."
Natural gas is sometimes touted by industry as a pathway to the hydrogen future because some aspects of hydrogen and natural gas distribution are similar — such as fuel storage, fueling, station siting, and training of technicians and drivers. It is generally believed that the knowledge gained from using natural gas for transportation will make the transition to a hydrogen economy easier.
Natural gas in its energy-dense liquefied form (LNG) is really the only option beyond diesel for heavy-duty applications. Batteries lack the necessary punch, while these trucks are large enough to serve as an economical platform for the equipment needed to deliver LNG to the engine. A last reason—and perhaps the most important, is simply that natural gas vehicles have made much more of an impact elsewhere, so why not here?
Because natural gas is a gaseous fuel at atmospheric pressure and occupies a considerably larger storage volume per unit of energy than refined petroleum liquids, it is stored aboard the vehicle as either a compressed gas or a liquid. The storage requirements are still much greater than those for refined petroleum products, which increases vehicle weight and tends to reduce fuel economy.
The Department of Energy says vehicles powered by natural gas are as safe as conventional gasoline or diesel vehicles, and their pressurized tanks have been designed to withstand severe impact, temperature, and environmental exposure. CNG is lighter than air, so if fuel were to escape in a crash, it would evaporate rather than create a puddle under the car.