Natural gas is a hydrocarbon gas mixture, primarily composed of methane (70% to 90%). This fossil fuel forms deep underground over millions of years from organic matter under oxygen-free conditions. Extracted and processed, natural gas is a significant global energy source, meeting worldwide demands.
Operational Advantages
Natural gas offers efficiency and versatility. Combined cycle power plants, which capture waste heat, achieve thermal efficiencies exceeding 60%, compared to coal plants’ average of 33%. This higher efficiency means less fuel is needed to generate electricity, reducing operational costs and environmental impact per unit of energy.
Natural gas combustion results in fewer air pollutants than coal or oil. It produces almost 50% less carbon dioxide (CO2) than coal per unit of energy and emits significantly lower levels of sulfur dioxide, nitrogen oxides, and particulate matter. This cleaner burning makes it a preferred option for electricity generation, residential heating, and industrial processes. Natural gas power plants can quickly adjust output, supporting intermittent renewable energy sources like solar and wind.
Environmental Footprint
While natural gas burns cleaner than other fossil fuels, its environmental footprint extends beyond combustion. It still contributes to atmospheric CO2 levels. Methane leakage, the primary component of natural gas, can escape into the atmosphere during extraction, processing, and transportation. Methane is a greenhouse gas with a global warming potential (GWP) 28 to 30 times higher than CO2 over 100 years, and 80 to 83 times higher over 20 years.
Hydraulic fracturing, or fracking, extracts natural gas from shale formations. This process injects large volumes of water, sand, and chemicals into wells to fracture rock and release gas. Water usage for a single well ranges from 1.5 million to 16 million gallons. While widespread groundwater contamination from fracking is debated, localized water quality impacts from chemical migration into groundwater have been observed. Natural gas infrastructure development, including pipelines, can also lead to land disturbance and deforestation.
Economic and Supply Chain Dynamics
Natural gas plays a role in global energy markets. It can be an affordable energy source in some regions. For countries with substantial reserves, domestic production contributes to energy independence, reducing reliance on foreign imports.
Natural gas infrastructure, including pipeline networks and storage facilities, is well-established globally. However, its price can be volatile, influenced by supply and demand shifts, weather patterns, and geopolitical events. Developing and maintaining this infrastructure also requires capital investment.
Safety and Health Implications
Natural gas use involves safety and public health considerations. It is flammable, and leaks risk explosions or fires if an ignition source is present and gas concentration in the air reaches 5% to 15%. To enhance safety and enable leak detection, mercaptan, an odorant smelling like rotten eggs, is added to the naturally odorless gas.
Within homes, natural gas appliances can impact indoor air quality. If unvented or poorly vented, they release combustion byproducts like carbon monoxide and nitrogen dioxide. Carbon monoxide is a colorless, odorless gas harmful in elevated concentrations. Proper ventilation and regular maintenance of natural gas appliances mitigate these indoor air quality concerns.