Researchers at West Virginia University are teaming with the Environmental Defense Fund and eight industry organizations on a two-year, $10 million project to study the extent of methane leakage associated with the routine operation of heavy-duty natural gas vehicles, and to identify specific actions needed to bring these emissions down.

With the U.S. trucking industry on the verge of a significant migration to natural gas vehicles, by 2020, 40% of new class 7 and 8 trucks sold could run on natural gas. Climate scientists have suggested that methane leakage during filling and transfer operations, possible with a wide-scale switch from diesel to natural gas as heavy truck fuel, could contribute more to global warming than the benefit of switching from diesel to natural gas would acheive.

Methane is the main ingredient in natural gas and a GHG pollutant many times more potent than carbon dioxide (CO2), the principal contributor to man-made climate change. Even small amounts of methane leakage across the natural gas supply chain can undermine the climate benefit of switching to natural gas from other fossil fuels for some period of time.

In a paper published last year, EDF scientists and other leading researchers examined the impact of potential fugitive emissions on the climate benefits of a switch from diesel to natural gas heavy-duty trucks.

According to the best available data, methane leak rates would need to be below 1% of gas produced in order to ensure that switching from diesel to natural gas produces climate benefits at all points in time. They also found that – using the EPA leakage rate estimates at that time – converting a fleet of heavy duty diesel vehicles to natural gas would result in increased climate warming for more than 250 years before any climate benefits were achieved.

"Currently, there is no empirical data on methane leaks associated with natural gas vehicles, only estimates, says EDF Chief Scientist, Steve Hamburg. "In order to fully understand the scope of the matter, and what the opportunity is to minimize methane emissions during the operation and refueling of natural gas vehicles, hard data is needed. This study brings together multiple, key stakeholders to advance methane science with measurements taken under real-world conditions. This information will help shape the public debate of the role that the increased usage of natural gas vehicles can have on our transportation sector.”

EDF is working with leading researchers and companies in a series of studies designed to better understand and characterize the methane leak rate across the natural gas supply chain. The studies will take direct measurements at various points across the production, gathering and processing, long distance transmission and storage, local distribution, and transportation. The first study, led by researchers at the University of Texas, is measuring emissions from natural gas production. Results will be released in the coming months.