Natural gas has many qualities that make it an efficient, relatively clean burning, and economical energy source. However, the production and use of natural gas have some environmental and safety issues to consider.
Natural gas is a relatively clean burning fossil fuel. Burning natural gas for energy results in fewer emissions of nearly all types of air pollutants and carbon dioxide than burning coal or petroleum products to produce an equal amount of energy. The clean burning properties of natural gas have contributed to increased natural gas use for electricity generation and as a transportation fuel for fleet vehicles in the US.
Natural gas is mainly methane, a strong greenhouse gas. Some natural gas leaks into the atmosphere from oil and natural gas wells, storage tanks, pipelines and processing plants. These leaks were the source of about 32% of total US methane emissions and about 4% of total US greenhouse gas emissions in 2015. The oil and natural gas industry takes steps to prevent natural gas leaks.
When geologists explore for natural gas deposits on land, they may disturb vegetation and soil with their vehicles. Drilling a natural gas well on land may require clearing and leveling an area around the well site. Well drilling activities produce air pollution and may disturb people, wildlife, and water resources. Laying pipelines that transport natural gas from wells usually requires clearing land to bury the pipe. Natural gas production can also produce large volumes of contaminated water. This water requires proper handling, storage, and treatment so that it does not pollute land and other waters. Natural gas wells and pipelines often have engines to run equipment and compressors, which produce air pollutants and noise.
In areas where natural gas is produced at oil wells but is not economical to transport for sale or contains high concentrations of hydrogen sulfide (a toxic gas), it is burned (flared) at well sites. Natural gas flaring produces CO2, carbon monoxide, sulfur dioxide, nitrogen oxides, and many other compounds, depending on the chemical composition of the natural gas and on how well the natural gas burns in the flare. However, flaring is safer than releasing natural gas into the air and results in lower overall greenhouse gas emissions because CO2 is not as strong a greenhouse gas as methane.
New drilling and natural gas recovery technologies significantly reduce the land area that is disturbed to develop oil and gas resources. Horizontal and directional drilling techniques make it possible to produce more natural gas from a single well than in the past, so fewer wells are necessary to develop a natural gas field.
Hydraulic fracturing of shale, sandstone and carbonate rock formations is opening up large reserves of natural gas that were previously too expensive to develop. Fracking involves pumping liquids under high pressure into a well to fracture the rock, which allows natural gas to escape from the rock. Producing natural gas with this technique has some effects on the environment:
Natural gas could be released to the atmosphere during and after well drilling, and the amount of these releases are under investigation.
Pros and cons of natural gas as an energy source
|Cleanest-burning fossil fuel|
|Used in combination with other fuels to decrease pollution in electricity|
|Made safer by adding artificial odor so leak is easily detectable|
|Easy to transport|
|Transportation costs are high|
|Lack of infrastructure makes gas resources unavailable in some areas|
|Burns cleanly, but still has emissions|
|Pipelines impact ecosystems|