Natural gas is a fossil fuel formed when layers of buried plants 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 carbon 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 in general
Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is also another resource found in 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 undergo processing to remove impurities, including water, to meet the specifications of the utilized natural gas engine. The by-products of 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. The world's first industrial extraction of natural gas started at Fredonia, NY in 1825. By 2009, 66 trillion cubic meters of natural gas had been used out of the total 850 trillion cubic meters of estimated remaining recoverable reserves, representing the usage of 8% of economically recoverable global reserves of natural gas. At 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.
Natural gas is a major source of electricity generation through the use of cogeneration, gas turbines and steam turbines. Most grid peaking power plants and some off-grid engine-generators use natural gas. Natural gas burns more cleanly than other hydrocarbon fuels, such as oil and coal, and produces less carbon dioxide per unit of energy released. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal.
Locally produced electric power and heat using natural gas powered cogeneration plants (CHP) is today an efficient and rapid way to cut carbon emissions.
Environmental performance improvement
Natural gas has the lowest levels of carbon dioxide production and is the cleanest of all the fossil fuels. GE Jenbacher gas engines generate electricity at high efficiency making the greatest use of the fuel source. The utilization of cogeneration technology for electricity and heat production locally helps minimize losses of electricity associated with its transmission from centralized power plants while significantly increasing the overall use of fuel. With the addition of carbon dioxide recovery systems carbon dioxide can be sequestered in plants or utilized in manufacturing processes improving the environmental performance.