Natural gas is a fossil fuel formed when layers of buried pl

  Natural gas is a fossil fuel formed when layers of buried plants, gases, and animals are exposed
to intense heat and pressure over thousands of years. The energy that the plants originally
obtained from the sun is stored in the form of chemical bonds in natural gas. Natural gas is a
nonrenewable resource because it cannot be replenished on a human time frame.Natural gas is
a hydrocarbon gas mixture consisting primarily of methane, but commonly includes varying amounts
of other higher alkanes and even a lesser percentage of carbon dioxide, nitrogen, and hydrogen
sulfide. Natural gas is an energy source often used for heating, cooking, and electricity
generation. It is also used as fuel for vehicles and as a chemical feedstock in the manufacture
of plastics and other commercially important organic chemicals.

  Natural gas is found in deep underground rock formations or associated with other hydrocarbon
reservoirs in coal beds and as methane clathrates. Petroleum is another resource and fossil fuel
found in close proximity to, and with natural gas. Most natural gas was created over time by two
mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms
in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature
and pressure, thermogenic gas is created from buried organic material.

  Before natural gas can be used as a fuel, it must be processed to remove impurities, including
water, to meet the specifications of marketable natural gas. The by-products of this processing
include ethane, propane, butanes, pentanes, and higher molecular weight hydrocarbons, hydrogen
sulfide (which may be converted into pure sulfur), carbon dioxide, water vapor, and sometimes
helium and nitrogen.

  Natural gas is often informally referred to simply as "gas", especially when compared to other
energy sources such as oil or coal. However, it is not to be confused with gasoline, especially
in North America, where the term gasoline is often shortened in colloquial usage to gas.

  Natural gas was used by the Chinese in about 500 BC. They discovered a way to transport gas
seeping from the ground in crude pipelines of bamboo to where it was used to boil sea water to
extract the salt.The world's first industrial extraction of natural gas started at Fredonia, NY, USA
in 1825.By 2009, 66 trillion cubic meters (or 8%) had been used out of the total 850 trillion cubic
meters of estimated remaining recoverable reserves of natural gas.Based on an estimated 2015
world consumption rate of about 3.4 trillion cubic meters of gas per year, the total estimated
remaining economically recoverable reserves of natural gas would last 250 years.