Natural Gas | Research & Encyclopedia Articles

Natural Gas

Natural gas is an indispensable energy resource throughout most of the industrialized world. In American homes, natural gas is used in furnaces, stoves, water heaters, clothes dryers, and other appliances. The fuel also supplies energy for numerous industrial processes and provides raw materials for making many products that we use every day. The largest sources of natural gas in the United States are found in Alaska, Texas, Oklahoma, western Pennsylvania, and Ohio.

The Chinese were the first people known to have discovered and used natural gas. As early as 940 B.C., they found gas underground and piped it through hollow bamboo poles to the seashore, where they burned it to boil off ocean water and collect the leftover salt. By 615 B.C., the Japanese were producing gas from similar wells. Other ancient civilizations may have accidentally discovered natural gas seeping up from the ground. When they learned that the gas would burn continuously, they built temples to house mysterious "eternal fires. " People traveled from faraway lands to visit these temples and marvel at this supernatural phenomenon.

In colonial North America, several natural gas seepages were discovered when they were accidentally set on fire. In the 1770s, French missionaries reported "pillars of fire" in the Ohio River valley, and George Washington described in wondering terms a "burning spring" on the banks of a river in West Virginia. Most scientists believe that natural gas was created by the same forces that formed petroleum, another fossil fuel.

In 1821, an American gunsmith named William Aaron Hart drilled the first natural gas well in the United States. It was covered with a large barrel, and the gas was directed through wooden pipes that were replaced a few years later with lead pipe. Although the well was only 27 ft (8.2 m) deep, it produced enough gas to illuminate nearby houses and stores in Fredonia, New York. Through the 1830s and 1840s, a few other gas wells were drilled in New York, Pennsylvania, and West Virginia. The first company to distribute and sell natural gas was established in Fredonia in 1865. But by then, oil had been discovered near Titusville, Pennsylvania, and in the oil rush that followed, natural gas was practically forgotten. Also, about 300 companies were already selling "manufactured" gas made from coal or oil. Gas lighting systems that burned manufactured gas had been established in many cities long before natural gas was discovered.

For many years, natural gas was used only in places that happened to be near gas wells, mainly because early pipes were unable to transport it much farther. In some towns that used natural gas for street lighting, the lights were left on during the day because it cost more to turn them off than it did to burn the gas. When new wells produced gas along with oil, the gas was usually just burned off, or flared.

In the late 1800s, the introduction of electric lighting nearly killed off the gas industry. However, customers of manufactured gas continued to use the fuel for cooking and heating, so gas companies never completely died out. Gradually, the natural gas industry began to recover as pipeline technology was improved and as larger quantities of natural gas were discovered. The first "long-distance" pipeline--only about 25 mi (40.2 km) long and less than a foot (30 m) in diameter--was built in the early 1870s to serve Rochester, New York. It was made of pine logs with holes bored through them.Iron pipe was also tested at that time in a 5.5 mi (8.8 km) pipeline serving 250 customers in Titusville, Pennsylvania, but for decades pipelines remained relatively short in length and small in diameter.

Then in the early 1900s, huge amounts of natural gas were found in Texas and Oklahoma, and in the 1920s modern seamless steel pipe was introduced. The strength of this new pipe, which could be electrically welded into long sections, allowed gas to be carried under higher pressures and thus in greater quantities. For the first time, natural gas transportation became profitable, and the American pipeline network grew by leaps and bounds through the 1930s and 1940s. By 1950, almost 300,000 mi (482,700 km) of gas pipelines had been laid--a length greater than that used to pipe oil. Soon it became routine for natural gas to be transported over distances of several hundred miles to the major centers of population and industry. As natural gas became available at prices lower than manufactured gas, customers switched to the cheaper fuel and consumption of natural gas increased phenomenally. Despite the loss of the lighting market, natural gas emerged as the most important heating and cooking fuel, and it gradually increased its share of the industrial market as well. Between 1940 and 1955, production of natural gas in the United States multiplied more than threefold. Gas now supplies more than one-fourth of all energy consumed in America.

In western Europe, however, the use of natural gas was virtually unknown until after World War II, when gas fields began to be developed in France and the Netherlands in the 1950s and in the North Sea, by England and Norway, in the 1960s. An American company came up with the idea of exporting natural gas to Europe by liquefying it at very cold temperatures and shipping it. In 1959, the first cargo of liquefied natural gas (LNG) crossed the Atlantic and was delivered to a specially built terminal in England.

Despite the huge amounts of natural gas that have been produced and consumed, new discoveries have continued to increase gas "reserves"--the amount of gas that is potentially recoverable. Exploring for natural gas is a complex process that demands the skills of geologists, physicists, chemists, and engineers. Once the right clues have been found above ground, surveyors map the area and samples of surface rocks are closely examined. Then underground structures are explored from the surface by means of instruments that identify rock layers from sound waves (seismographs) or from changes in gravity and magnetism (gravity meters and magnetometers). Still, no aboveground technique can prove the presence of gas, and an expensive well must be drilled for confirmation. On land, wells typically cost about $500,000. Unusually deep wells, and offshore wells drilled in water, cost much more.

Natural gas, like petroleum, is a mixture of many organic substances. It consists mainly of methane, the simplest hydrocarbon, as well as small amounts of heavier, more complex hydrocarbons such as ethane, butane and propane. Some natural gas also contains impurities such as hydrogen sulfide ("sour" gas), carbon dioxide ("acid" gas), and water ("wet" gas). Before entering the transmission pipeline, natural gas is processed to remove impurities and extract valuable hydrocarbons.Sulfur and carbon dioxide are sometimes recovered and sold as byproducts. Propane and butane are usually liquefied under pressure and sold separately as LPG (liquefied petroleum gas). LPG is commonly used as a substitute for natural gas in rural areas that are not served by transmission pipelines.

Natural gas has its origins in decayed living matter, most likely as the result of the action of bacteria upon dead animal and plant material. In order for most bacteria to effectively break down organic matter to hydrocarbons, there must be low levels of oxygen present. This would mean that the decaying matter was buried (most likely under water) before it could be completely degraded to carbon dioxide and water. Conditions such as this are likely to have been met in coastal areas where sedimentary rocks and marine bacteria are common. The actions of heat and pressure along with bacteria produced a mixture of hydrocarbons. The smaller molecules that exist as gases were then either trapped in porous rocks or in underground reservoirs where they formed sources of hydrocarbon fuels.

Recently, in light of environmental concerns, natural gas has begun to be reconsidered as a fuel for generating electricity. Natural gas is the cleanest burning fossil fuel, producing mostly just water vapor and carbon dioxide. Several gas power generation technologies have been advanced over the years, including a process developed by Meredith Gourdine, an American physicist, that uses the principles of electrogasdynamics (EGD). Cars have also been produced which use natural gas as their primary fuel source. In the future, these cars may become more common because of their lower environmental impact.