A report in the June 21, 2018 issue of Science has the potential to change the economics of natural gas. For decades natural gas has been perceived by governments, and by many — though not all — climate change experts as an environmentally appropriate transition fuel between high carbon coal and oil and a low carbon future.
The report in Science suggests that the benefits of natural gas may have been overestimated because of leaks in the production, distribution, and utilization systems. Fixing those leaks will be a very expensive undertaking and the costs will be passed on to the consumers of natural gas. It is not unforeseeable that the cost of fixing leaks on a global scale will be so great as to remove natural gas as an environmentally acceptable transition fuel.
The report, by a team of researchers from 15 respected U.S. universities and the Earth System Research Laboratory of the National Oceanic and Atmospheric Administration, found that the level of leakage from the U.S. oil and natural gas supply chain is equivalent to 2.3% of gross U.S. gas production. This number is approximately 60% higher than the U.S. Environmental Protection Agency estimate.
Given that methane, the principle component of natural gas, is a much more potent greenhouse gas than carbon dioxide, this reassessment of the amount of methane being released into the atmosphere from natural gas leaks means that the total climate impact of the natural gas system is approximately double the impact of the carbon dioxide produced by natural gas as a fuel in combustion devices. In short, and in the short-term, natural gas may be worse for the climate system than coal!
The good news is that methane is a relatively short-lived compound in the atmosphere. Significant emission reductions are possible and substantially reducing the leaks will, over time, improve the environmental performance of natural gas as a fuel, but until those leak-stop initiatives are undertaken, it is going to be difficult to view natural gas as an environmentally beneficial fuel.
The report’s findings likely also apply to biogas systems, especially where the biogas is distributed through third-party utility systems.
The report is also interesting for its methodology. Natural gas emissions can be measured either at the facility level using a range of metering devices, or on a regional basis using aircraft, satellites, or tower networks. The former approach is classified as “Bottom Up” while the latter is viewed as “Top Down”.
Top Down data has been published for nine oil- and natural gas-producing areas in the U.S., including about 33% of natural gas, about 24% of oil production, and about 14% of all wells. Bottom Up studies have been conducted on equipment or facilities that are expected to represent the vast majority of emissions from the oil and natural gas supply chain. The report in Science finds an acceptable degree of congruence between the two approaches to measurement of natural gas releases and is based on a combination of data from both types of measurement.
The researchers’ methodology indicates that roughly 85% of natural gas emissions occur in the production and gathering of natural gas, and that technology can control leaks when it operates as designed, but that a significant percentage of the current methane releases to the atmosphere are from abnormal operating conditions and equipment malfunctions.
Also worth noting is that the methodology employed by the research team was not able to update emissions from local distribution and end use of natural gas. The team indicates, however, that local distribution emissions are significant, exceeding the current inventory estimate, and that end-user emissions might also be important. Hence a review of the impacts of natural gas on climate will also likely focus attention on end users as well as on the carbon footprint of the delivered gas.
This is only one report and no doubt both the natural gas industry and governments will study the results in a critical manner and commission other studies that may produce different results. However, the team that produced this research report is, at least superficially, as blue chip as they come and the results are reasonably compelling.
Large energy consumers using natural gas and claiming environmental benefits may want to review the systems which they have to control leaks. They might also consider the economic consequences of a downgrade to the carbon benefits that natural gas has been purported to provide or from an increase in the cost of natural gas resulting from deployment of less failure-prone systems.
Colin Isaacs is a scientist and analyst with CIAL Group who focuses on sustainable development for business. He has been involved in undertaking and reviewing a number of LCA studies. He can be reached at (416) 410-0432 (phone); (416) 362-5231 (fax); and email@example.com (e-mail).