History of Natural Gas
The ancient peoples of Greece, Persia, and India discovered natural gas many centuries ago. The people were mystified by the burning springs created when natural gas seeping from cracks in the ground was ignited by lightning. They sometimes built temples around these eternal flames so they could worship the fire.
About 2,500 years ago, the Chinese recognized that natural gas could be put to work. The Chinese piped the gas from shallow wells and burned it under large pans to evaporate sea water for salt.
Natural gas was first used in America to illuminate the streets of Baltimore in 1816. Soon after, in 1821, William Hart dug the first successful American natural gas well in Fredonia, New York. His well was 27 feet deep, quite shallow compared to today's wells. The Fredonia Gas Light Company opened its doors in 1858 as the nation's first natural gas company. By 1900, natural gas had been discovered in 17 states. In the past 40 years, the use of natural gas has grown dramatically. Today, natural gas accounts for about a quarter of the energy we use.
Producing Natural Gas
Natural gas can be hard to find since it can be trapped in porous rocks deep underground. Scientists use many methods to find natural gas deposits. They may look at surface rocks to find clues about underground formations. They may set off small explosions or drop heavy weights on the surface and record the sound waves as they bounce back from the rock layers underground. They also may measure the gravitational pull of rock masses deep within the earth.
If test results are promising, the scientists may recommend drilling to find the natural gas deposits. Natural gas wells average 6,000 feet deep and can cost more than $75 per foot to drill, so it's important to choose sites carefully. On average, 27 out of every 100 exploratory wells produce gas. The others come up "dry." (The odds are better for developmental wells-wells drilled on known gas fields. On average, 80 out of every 100 developmental wells yield gas.) Natural gas can be found in pockets by itself or in petroleum deposits.
After natural gas comes out of the ground, it goes to a processing plant where it is cleaned of impurities and separated into its various components. Approximately 90 percent of natural gas is composed of methane, but it also contains small amounts of other gases such as propane and butane.
Natural gas may also come from several other sources. One source is the gas found in coalbeds. Until recently, coalbed gas was just, considered a safety hazard to miners, but now it is a valuable source of natural gas.
Another source of natural gas is the gas produced in landfills. Landfill gas is considered a renewable source of natural gas since it comes from decaying garbage. The gas from coalbeds and landfills accounts for three percent of the total gas supply today, yet their contribution could double by the year 2010.
Today natural gas is produced in 32 states, though just three states--Texas, Louisiana, and Oklahoma-produce 61 percent of the country's natural gas. Altogether, the United States produces nearly 22 percent of the world's natural gas each year. In 1994 the United States imported 12 percent of its natural gas from other countries-mostly from Mexico and Canada.
Transporting and Storing Natural Gas
How does natural gas get to you, the consumer? Usually by pipeline. More than one million miles of underground pipelines link natural gas fields to major cities across the United States. Natural gas is sometimes transported thousands of miles by pipeline to its final destination. A machine called a compressor increases the pressure of the gas, forcing the gas to move along the pipelines. Compressor stations, which are spaced about 50 to 100 miles apart, move the gas along the pipelines at about 15 miles per hour.
Some gas moved along this subterranean highway is temporarily stored in huge underground reservoirs. The underground reservoirs are typically filled in the summer so there will be enough natural gas during the winter heating season.
Eventually, the gas reaches the "city gate" of a local gas utility. Here, the pressure is reduced and an odorant is added so leaking gas can be detected. Local gas companies use smaller pipes to carry gas the last few miles to homes and businesses. A gas meter measures the volume of gas a consumer uses.
