Payoff from Idling Coal Plants Overestimated, Researchers Say

Four researchers from Carnegie Mellon University’s Green Design Institute discuss their more conservative estimates of greenhouse gas emission reductions in two papers this month.

A quartet of researchers at Carnegie Mellon University's Green Design Institute conclude in two new papers that ignoring uncertainty in any coal-to-natural-gas transition for generating electricity can make a substantial difference in estimating the net environmental effect of the change. Researchers Aranya Venkatesh, W. Michael Griffin, H. Scott Matthews, and Paulina Jaramillo concluded life cycle assessment (LCA, the study of impacts that occur from cradle to grave) can be useful in these analyses.

Their papers appear in the October issue of Environmental Research Letters and in Environmental Science and Technology, according to a news release posted by the university.

While many studies simply examine different emissions from coal and natural gas plants, suggesting roughly a 50 percent reduction in greenhouse gas emissions, these researchers conclude the reduction is likely to be 7-15 percent instead because of changes in grid operation in response to price changes in natural gas.

"As natural gas prices go down, it becomes cheaper to operate natural gas plants, and some of these plants start being operated more often. This results in some coal plants being operated less often. However, given certain technical constraints related to the operation of existing power plants, the displacement of coal-based generation is limited," said Jaramillo, an assistant research professor in CMU's Department of Engineering and Public Policy. To cut emissions by 50 percent using natural gas would require a significant retirement of coal plants and building new natural gas plants.

The second paper examined the uncertainty in emissions that could be expected from retiring coal-fired power plants. While it suggests reductions in greenhouse gas emissions from limited retirement of coal plants will be minimal, emissions of sulfur and nitrogen oxides would be substantial, up to 25 percent, in some areas. (The paper focuses on up to 7 gigawatts of coal capacity being retired without building new power plants to replace them.) "We found that if expected coal plants retire, that alone will not bring us dramatic reductions in climate change inducing greenhouse gas emissions," said Matthews, a professor in CMU's Civil and Environmental Engineering and EPP departments.

"In addition, the benefits achieved from reducing emissions of sulfur and nitrogen oxides, while substantial in aggregate measures, will not be evenly distributed; and while some counties will see reductions in the emissions of these criteria air pollutants, some counties will see increases," Jaramillo said.

Download Center

  • Waste Management in 2021: Accelerate Your Success with Technology

    Join waste management experts on February 23rd for a live best practice session webinar. You’ll learn how to take your waste program to the next level with visual location, barcoding, and mobility. Register now.

  • Green Quadrant EHS Software 2021

    Reserve your copy of the new report by independent analyst firm, Verdantix, to get a detailed, fact-based comparison of the 22 most prominent EHS software vendors in the industry.

  • Your Guide to Environmental Metrics that Drive Performance

    Translating sustainability into action starts with implementing the right metrics to assess your environmental risk and performance. Learn how to design metrics that improve your decision-making process and drive enterprise performance.

  • 5 Keys to Best-in-Class Chemical Management

    Running a safe chemical program is challenging and complex: from knowing what's on-site to proper handling and disposal - all while navigating regulatory changes. Learn the best ways to mitigate chemical risk, get the most value out of your data, and gain buy-in for a chemical management solution.

  • Unpacking ESG: 6 Questions You Were Too Afraid to Ask

    Environmental and Sustainability experts from Arcadis and Cority answer 6 of the most pressing questions EHS professionals have about getting started with Environmental, Social, and Governance (ESG) reporting.

  • Industry Safe