Initially, a large amount of gas produced in oil and gas fields was burned in flare systems. However, natural gas has become the most important fossil fuel resource in recent decades and the most essential source of energy in general. There are various ways to use natural gas that are more economical than flaring it, such as using it to generate electricity in natural gas power plants, injecting it into wells for advanced oil recovery, providing it to petrochemical plants as a raw material to produce rubber, glass, steel, and paint, and liquefying it for domestic and industrial activities. The development of the gas energy industry in recent decades was caused by many factors. One factor is related to the usage and application of natural gas. In the early days of the natural gas industry, the gas was mainly used to light streetlamps and houses. Now, however, natural gas is the most widely used source of energy in chemical and power plants. Additionally, natural gas is used for cooling and heating homes and businesses. Table 1.6 shows natural gas consumption as a percentage of overall energy consumption in Europe in different sectors. The United States has similar rates and patterns of consumption. Statistics showed that natural gas provided close to 24% of energy used over the three-year period from 2000 to 2003. As natural gas is known as a clean source of energy and because of increasing concerns about air pollution and the environment, usage of natural gas is predicted to increase in the future.