Can Eliminating Methane Emissions Make Natural Gas Clean?
by Bob Shively, Enerdynamics President and Lead Facilitator
Once accepted as the “clean” fossil fuel that would provide the bridge between an energy system based on fossil fuels and one based on renewable energy, natural gas is less favorable among many environmentalists. The key issue is natural gas’ contribution to greenhouse gas emissions. Methane, the primary component of natural gas, has significantly lower greenhouse gas emissions when combusted than other commonly used fossil fuels such as coal and fuel oil.
Source: Energy Information Administration
And, because modern combined-cycle power plants are highly efficient, the greenhouse gas emissions associated with power generation are even more favorable to natural gas:
Source: Energy Information Administration for the year 2022
But what these numbers don’t consider is the raw methane that is released into the atmosphere prior to the gas arriving at the power plant. Raw natural gas released into the atmosphere has a dramatic effect. Over the first 20 years of natural gas being released, a pound of methane is 84 times more potent than a pound of carbon dioxide [1]. Given significant methane releases in the gas production and delivery system, some researchers [2] contend that the overall greenhouse gas impacts of natural gas generation are greater than that of coal, although this is open to debate. As energy-consuming nations around the world rush to build new liquified natural gas (LNG) facilities and as coal-fired generation is increasingly replaced with natural gas units, greenhouse gas emissions from raw methane have become a significant concern. In July the White House convened a methane summit. At the recently concluded U.N. Climate Change Conference known as COP28 $1 billion was pledged for new grants to reduce methane emissions, and the number of countries joining the Global Methane Pledge reached 155. The pledge is a voluntary framework for cutting methane emissions by 30% by 2030.
From where do methane emissions come?
Methane emissions occur throughout the gas production and delivery system according to a study by the Gas Index project. Most significant are emissions in the production sector, but emissions in transmission pipelines, distribution systems, meters, and buildings cannot be ignored. When totaled up, emissions for these sectors combined are almost equal to emissions from production for residential and commercial customers. Meanwhile, for gas such as LNG that is transported long distances, additional significant emissions occur in the liquefaction and shipping sectors.
Source: The Gas Index Report 2020
Source: International Gas Union Global Voice of Gas, Issue 3 Volume 03
What can be done about emissions?
While it's clear that the sector with the largest emissions is the production sector, let’s take a look at how each sector can reduce its greenhouse gas footprint:
- Production: Monitoring to identify and fix sources of emissions, properly seal abandoned wells, ensure flares at oil wells are working properly, capture methane during maintenance of wells and gathering lines, install vapor capture equipment on storage tanks, identify improperly sealed non-producing wells and cap to prevent ongoing emissions.
- Transmission and distribution: Monitor for leaks and repair lower-level leaks that in the past would have been considered acceptable, capture methane during maintenance rather than venting, avoid venting methane during operations, replace gas turbine compressor stations with electric drive powered by zero-carbon electricity.
- Metering: Increase leak detection of meters, repair all leaks, and replace all faulty meters.
- Buildings: Implement electrification of end uses, perform regular maintenance of gas appliances, monitor for leaks.
- LNG liquefaction: Implement carbon capture and storage, replace gas generation with zero-carbon electricity.
- LNG shipping: Capture boil-off for use as fuel or for re-liquefaction.
- LNG regasification: Shift electric source to zero-carbon electricity.
It appears that many in the gas industry believe that cutting greenhouse gas emissions will be necessary for natural gas to hold onto its claim of being a useful bridge fuel. The alternative is to see more and more governments and advocacy groups not only calling for deeper regulation of the natural gas industry but also speeding up the transition away from natural gas. Actions by key gas industry players including producers, midstream companies, transmission pipelines, distribution companies, and participants along the LNG value chain will be critical toward determining the future role of natural gas.
