Natural gas is gaseous fossil fuel made up of a mixture of hydrocarbons—mainly methane—and is produced either from gas wells or in conjunction with crude oil production. Natural gas is recovered in the course of recovering petroleum and is found in oil fields and natural gas fields, and in coal beds.
Natural gas is often stored in underground caverns like depleted gas reservoirs or salt domes where it is stored during low demand and used during higher demand periods. Natural gas is volatile and is lighter than air, and tends to dissipate into the atmosphere. But when natural gas is confined it can reach explosive levels and, if ignited, result in explosion.
The price of natural gas varies greatly depending on location and type of consumer, but as of 2006 a price of $10 per 1000 cubic feet is typical in the U.S. Natural gas is traded as a futures contract on the New York Mercantile Exchange.
LNG
Liquefied natural gas (LNG) or propane is comparable to petrol and diesel fuels' energy output and produces less pollution. However, its relatively high cost of production and expensive cryogenic storage tanks impede most commercial use. It is used in natural gas vehicles, although these are more commonly designed to use compressed natural gas.
CNG
Compressed natural gas (CNG) is natural gas pressurized and stored in welding bottle-like tanks at high pressures. Typically, it is the same composition as pipeline gas, with some of the water removed. CNG is used as vehicle fuel. LNG can be used to make CNG.
Environmental benefits
Natural gas burns cleaner than other fossil fuels, such as oil and coal, and produces less greenhouse gas per unit energy released.
For an equivalent amount of heat, burning natural gas produces about 30 percent less carbon dioxide than petroleum and about 45 percent less than coal.
Biomethane is a renewable gas that can be processed from the gas released from landfills, sewage, animal waste and even other biomaterials (through cellousic processing).
Where can I find – fuel and vehicles?
There are more than 5 million natural gas vehicles worldwide. And the International Association of Natural Gas Vehicles is working toward raising that number to 50 million globally by 2020.
Dedicated natural gas vehicles
- Chevrolet Silverado/GMC Sierra (requires purchase of vehicle plus GM installed conversion kit)
- Honda Civic GX (30 city/ 34 Hwy) was named “America’s Greenest Car” by the American Council for an Energy-Efficient Economy (ACEEE)
Ohio conversion (from gasoline to CNG) locations certified by the EPA
Controversy
The major difficulty in the use of natural gas is transportation and storage because of its low density. Existing capacity of pipelines in North America are close to reaching capacity, prompting discussion of potential shortages.
The natural gas crisis is typically described by the increasing price of natural gas in North America over the last few years, due to the decline in indigenous supply and the increase in demand for electricity generation. Indigenous supply in the U.S. has fallen due to a drop in production and continuing growth in demand. The price has become so high that many industrial users, mainly in the petrochemical industry, have closed plants.
The natural gas supply is said to peak around the year 2030—20 years after the peak of oil. It is also projected that the world's supply of natural gas should be exhausted around the year 2085.
Concern about compressed natural gas in vehicles are almost non-existent, due to the escaping nature of the gas, and the concentrations needed to trigger explosions.
