The Center for Alternative Fuels, Engines and Emissions (CAFEE) at West Virginia University (WVU) has initiated a new study that aims to determine fugitive emissions of methane associated with routine operation of natural gas fleet vehicles fueled by compressed (CNG) or liquefied (LNG) natural gas.
Natural gas powered vehicles are expected to play an increasing role in meeting future transportation needs. This study will measure methane leaks that occur at various stages in the refueling and operations of heavy duty natural gas vehicles to provide scientific insights given the projections of industry growth.
Natural gas is a cleaner-burning fossil fuel that consists mostly of methane. Natural gas vehicles have the potential to produce fewer greenhouse emissions than diesel fuel if methane leaks are kept low. Uncombusted natural gas, when released into the atmosphere, can accelerate climate change due to the potency of methane.
Environmental Defense Fund is collaborating with academic and industry stakeholders on numerous scientific studies to characterize methane emissions from the production and delivery of natural gas to end users. This comprehensive research series will provide empirical methane data collected at various points across the natural gas supply chain. Results of the first study focused on production will be released in the coming months.
EDF, along with industry and research organizations, is sponsoring this new project led by CAFEE to better understand methane leakage associated with natural gas vehicles and fueling stations. Other sponsors include the American Gas Association, International Council on Clean Transportation, PepsiCo, Shell, Volvo Group, Waste Management, Cummins Westport and Westport Innovations. Sponsors are providing access to vehicles or facilities, and a number of other industry participants are contributing equipment for testing.
The study will directly measure methane emissions at CNG and LNG refueling sites and maintenance facilities that result from the operation of natural gas powered heavy duty vehicles. Final results are expected to be released in a peer-reviewed journal late 2013 or early 2014 and to assist industry in developing improvements to fueling operations and identifying best practices for minimizing leakage.
“CAFEE has a 24-year history of advanced energy research with rapid delivery of data and research products,” said Nigel Clark, George Berry Chair of Engineering at WVU and principal investigator on the project. “This is right in CAFEE’s wheelhouse. Our faculty, students and research staff have conducted numerous prior studies involving natural gas engines and vehicles, heavy-duty emissions inventory and modeling in the environmental and transportation sectors.”
Vehicles to be tested include transit buses, tractor-trailers and vocational vehicle fleets with access to private and public fueling sites. Measurements gathered during evaluations associated with this program will be combined with available vehicle exhaust emissions data to provide a statistically valid view of a modern natural gas fleet.
CAFEE researchers will also gather data on methane emissions from fueling stations and maintenance facilities through a combination of leak detections, leak measurements, operational and maintenance procedure review, and equipment audits, which will all be used to develop a consolidated database and model.
To assist them in their methane quantification efforts, the researchers constructed a mobile dilution sampling system. A scientific advisory panel composed of professors and experts in the fields relevant to the study will also serve as independent advisors, charged with reviewing the appropriateness of the methodologies, results and their statistical methods.