Natural Gas

Natural gas is made up of just two elements: carbon and hydrogen. It is a fossil fuel that is believed to have been formed from the organic remains of tiny sea animals and plants that date back 300 to 400 million years. These organic remains decayed and converted into gas and oil under pressure, combined with the heat of the Earth. Raw natural gas is primarily composed of methane, a natural compound that is formed when plant and animal matter decays. Natural gas is environmentally more benign compared to other fossil fuels like coal and petroleum, as combustion of natural gas generates less sulfur, carbon, and nitrogen than burning other fossil fuels. Furthermore, natural gas also emanates less ash particulate into the air when burned. Burning natural gas for power generation produces roughly half as much carbon dioxide (CO2) as coal in power production.

Natural gas is usually trapped in porous rocks deep underground but may also be found in seams of coal, known as coalbed methane. Natural gas comes out of the ground as a gas; oil, gasoline, and other hydrocarbons are recovered in a mixed liquid called crude oil. Natural gas may also be produced in landfills comprised of decaying garbage (known as landfill gas). Oil and natural gas wells have traditionally been drilled vertically, at depths ranging from a few thousand ft. to as deep as 5 mi. Today, advances in drilling technology allow oil and natural gas companies to reach more reserves while reducing environmental impact by reducing the surface “footprint” of drilling operations, drilling smaller holes, generating less waste, creating less noise, avoiding sensitive ecosystems, and completing operations more quickly.

Considered from a technology perspective, natural gas and renewable sources such as wind and solar can complement each other. For instance, natural gas–fired turbines can be used to generate electricity when the wind isn’t blowing or the sun isn’t shining. Furthermore, it is not technologically difficult to substitute natural gas for gasoline or diesel fuel in cars and trucks, although this approach would not reduce greenhouse gas (GHG) emissions nearly as much as replacing coal in power production. A natural gas–powered car emits about 25 percent less CO2 than a gasolinepowered vehicle. Although replacing other fossil fuels with natural gas can lower emissions of GHGs and local pollutants, a trajectory toward 3.6 degrees F (2 degrees C) would still require a greater shift to renewables, increased energy efficiency, and deployment of new technologies such as carbon capture and storage (CCS), which could reduce emissions from gas-fired plants.

Furthermore, despite its low carbon intensity, natural gas is still a fossil fuel. Thus, increased utilization of gas in the energy mix may increase dependence on fossil fuels and lead to delay and disincentives in investment of renewable and lowcarbon technological innovation. At best, natural gas could be considered a transitory fuel, rather than a panacea for combating climate change. Globally, natural gas resources appear adequate and widely dispersed geographically, which can help improve energy security. Considered from the supply side, most major geographic regions have recoverable natural gas resources that amount to at least 75 years’ worth of current consumption. However, there is a clear distinction between resources of natural gas that largely remain underground and the amount of natural gas that is economically recoverable.

Furthermore, timely and successful development of these resources is challenging and contingent upon a plethora of factors, including sound government policy to incentivize and guide the transition to natural gas; technological capability; electric power regulation at the local, state, and federal levels; effective federal and state oversight of natural gas exploration and the extraction process; putting a price on GHG emissions; and market conditions. Considered from the demand perspective, natural gas as a fuel could be crucial in the medium term for countries and regions that are urbanizing along with a concomitant growth in energy demand, such as China, India, and the Middle East. Hence, the growth and emergence of these countries and regions are expected to largely determine the extent to which natural gas use expands over the next 25 years.