The Environmental Defense Fund (EDF) and industry partners have poured millions of dollars into investigating methane emissions from the U.S. natural gas industry over the past few years and the results could have the potential of significantly influencing the EPA into changing its emissions regulations.
Mechanical engineering professor and director of the CSU Engines and Energy Conversion Laboratory, Anthony Marchese, led a $1.9 million EDF study that assessed emissions from gathering and processing facilities, which are potentially major sources of methane emissions.
EDF’s overall goal is to quantify the amount of methane leaking into the atmosphere from the natural gas supply chain. Identification of the sources of methane emissions will suggest the measures that can be taken to reduce future emissions. Currently, the net leakage rate in this sector is not well known, which poses a problem when understanding its effects, if any, to global warming, human health and society.
On an intense timeline, from October 2013 to April 2014, Marchese and his team collected and assessed data from 114 gathering facilities and 16 processing plants across 13 states to determine if methane leakage occurred at higher rates than anticipated. Other sectors, also supported by the EDF, evaluated other phases of the supply chain process. “This is an exciting study because it is, by far, the largest and most comprehensive data set ever collected on direct methane emissions from the gathering sector,” Marchese said.
The results determined that 30 percent of the gathering facilities accounted for 80 percent of the methane emissions measured, and methane loss rates at processing plants were much lower than that at gathering facilities. Marchese noted that, “Processing plants are generally much larger and permanently staffed, and are required to report methane emissions to the EPA. They are also required by federal law to repair any leaks within five days of detection. Most gathering facilities aren’t subject to those federal regulations.”
With this knowledge, Marchese believes that the EPA will reevaluate the need to regulate methane emissions in gathering facilities, just as they do in processing facilities, to eliminate higher loss rates.
Once the results are captured from all 16 of EDF’s emissions studies, a more accurate estimation of how much methane is actually being released into the atmosphere via the natural gas supply chain will be published. Marchese and his team are currently completing a publication on a Monte Carlo simulation that uses the methane measurement results to estimate the total methane emissions from all U.S. gathering and processing facilities. However, a large chunk of data is still missing – leakage from the hundreds of thousands of miles of gathering pipelines that lie between the wells and the gathering facilities.
Stay tuned for up-to-date information on this developing research.