Natural gas supplies about 23.8 percent of the world's energy and about 24 percent of the United States' energy. Most of the world's natural gas reserves are found in the Middle East (40 percent) and eastern Europe (26 percent). The United States has about 4 percent of the world's gas reserves. Known gas reserves are expected to last about 63 years at current consumption levels. If new technologies are developed that could extract currently known but uneconomic gas deposits, the supply could last roughly 200 years.

At the processing plant, raw natural gas is first sent through a separator. The methane is separated, dried of moisture, cleaned of impurities, and pumped into pipelines for distribution. The valuable heavier hydrocarbons, including propane, are removed, processed, and sent to market for a variety of uses.

As the pipeline-quality gas leaves the processing plant, it enters a compressor station where it is pressurized for transmission in pipelines across the country. As a pipeline nears a city, some of the gas is diverted through a city gate where its pressure is reduced and it is measured and sold to a local natural gas utility. From the city gate, the utility distributes the gas through a network of smaller underground pipelines called mains. Smaller lines called services connect with the mains and go directly to the consumer.