Natural gas is a hydrocarbon gas mixture primarily composed of methane (CH4), about 90% of its content. It also contains smaller amounts of other hydrocarbons like ethane, propane, and butane, along with traces of non-hydrocarbon gases such as carbon dioxide and nitrogen. Formed over millions of years from decomposed organic matter under heat and pressure, it is extracted through drilling. It serves as a global energy source for heating, cooking, electricity generation, and industrial processes.
Environmental Considerations
Burning natural gas produces fewer air pollutants and carbon dioxide (CO2) emissions than coal and oil. For instance, its combustion emits approximately 50% less CO2 than coal and about 30% less than oil. It is a cleaner-burning fossil fuel, reducing sulfur dioxide (SOx), nitrogen oxides (NOx), and particulate matter. Its cleaner combustion has led to increased use in electricity generation and as a vehicle fuel.
Despite these benefits, natural gas combustion still releases CO2, a greenhouse gas, contributing to climate change. Methane (CH4) leakage throughout the supply chain, including extraction, processing, and transport, is a significant environmental concern. Methane is a potent greenhouse gas, trapping over 80 times more heat than CO2 over a 20-year period, although it has a shorter atmospheric lifespan. Methane emissions from natural gas systems contribute a notable portion of total methane and overall greenhouse gas emissions. The climate impact of natural gas can become comparable to that of coal if methane leakage rates are substantial, with some research suggesting parity at leakage rates as low as 0.2% to 2%.
Supply Reliability and Economic Aspects
Found globally, natural gas contributes to energy security due to its widespread availability. It provides reliable baseload power for electricity generation, supplying a consistent minimum amount of electricity. Unlike intermittent renewable sources such as wind and solar, natural gas power plants can be quickly dispatched to meet fluctuating demand, offering flexibility and stability to the grid. Extensive existing infrastructure, including pipelines and storage facilities, supports its efficient distribution.
However, natural gas is a non-renewable fossil fuel, formed over geological timescales, meaning its finite reserves cannot be replenished on a human timescale. While new discoveries and extraction technologies continue to expand the usable supply, the resource is ultimately limited. Concentrated supply in certain regions leads to geopolitical complexities and dependencies, disrupting supply chains and creating market uncertainty. Price volatility is influenced by supply and demand, weather, and geopolitical events.
Extraction and Distribution Safety
Natural gas extraction, particularly hydraulic fracturing (fracking), a common method for accessing shale gas, raises safety concerns. This process involves injecting water, sand, and chemicals into rock formations, potentially leading to water contamination from fracking fluids or wastewater disposal. Induced seismicity, or small earthquakes, has also been linked to fracking activities. Beyond extraction, the extensive network of pipelines and storage facilities presents safety risks.
Leaks from pipelines and storage facilities can result in hazardous explosions or fires due to natural gas flammability. These incidents can cause loss of life, injuries, and significant property damage, with hundreds occurring annually. Infrastructure failures, including corrosion or equipment malfunctions, are common causes of such incidents. Underground storage facilities, while enabling efficient management of supply and demand, also pose risks such as gas migration and potential contamination of groundwater.