Natural gas critical for energy security, carbon emission reduction
Ahead of the release of its World Environmental Outlook scheduled for next month, the International Energy Association (IEA) has said the role that natural gas can play in the future of global energy is inextricably linked to its ability to help address environmental problems.
With concerns about air quality and climate change looming large, natural gas offers many potential benefits if it displaces more polluting fuels. This is especially true given limits to how quickly renewable energy options can be scaled up and that cost-effective zero-carbon option can be harder to find in some parts of the energy system.
While there is very little dispute about the emissions associated with natural gas combustion but there is much less consensus over the level of direct methane emissions that can occur – whether by accident or by design – on the path from oil or gas production to final consumer.
This is a critical issue for the long-term natural gas outlook: methane is a potent greenhouse gas and the uncertainty over the level of methane emitted to the atmosphere raises questions about the extent of the climate benefits that gas can bring.
But gas has advantages over other fossil fuels. CO2 emissions (per unit of energy produced) from gas are around 40% lower than coal and around 20% lower than oil. The edge of natural gas over other combustible fuels is reinforced when considering emissions of the main air pollutants, including fine particulate matter (PM2.5), sulfur oxides, mainly sulfur dioxide (SO2), and nitrogen oxides (NOX). These three pollutants are responsible for the most widespread impacts of air pollution, according to the IEA.
Gas combustion produces significant levels of nitrogen oxides (NOX), with around 10% of global NOX emissions coming from the use of gas. However, it produces virtually no SO2 emissions and negligible levels of PM2.5 (See figure below). Coal use dominates global emissions of SO2, oil products used for transport are the dominant source of NOX, while the combustion of wood and other traditional solid fuels are responsible for more than half of current PM2.5 emissions according to the organisation.