Pump-to-Wheels Methane Emissions from the Heavy-Duty Transportation Sector

Abstract

Pump-to-wheels (PTW) methane emissions from the heavy-duty (HD) transportation sector, which have climate change implications, are poorly documented. In this study, methane emissions from HD natural gas fueled vehicles and the compressed natural gas (CNG) and liquefied natural gas (LNG) fueling stations that serve them were characterized. A novel measurement system was developed to quantify methane leaks and losses. Engine related emissions were characterized from twenty-two natural gas fueled transit buses, refuse trucks, and over-the-road (OTR) tractors. Losses from six LNG and eight CNG stations were characterized during compression, fuel delivery, storage, and from leaks. Cryogenic boil-off pressure rise and pressure control venting from LNG storage tanks were characterized using theoretical and empirical modeling. Field and laboratory observations of LNG storage tanks were used for model development and evaluation. PTW emissions were combined with a specific scenario to view emissions as a percent of throughput. Vehicle tailpipe and crankcase emissions were the highest sources of methane. Data from this research are being applied by the authors to develop models to forecast methane emissions from the future HD transportation sector.

Highly Active and Stable Pd−GaOx/Al2O3 Catalysts Derived from Intermetallic Pd5Ga3 Nanocrystals for Methane Combustion

“…This result indicates that the catalyst deactivation induced by CO 2 introduction was reversible, and it can be proved by the result of FT-IR spectra (Figure S14 in supporting information). According to the literature, [45,46] the absorption bands of the CO 3 2À , HCO 3 À , and CÀ O species were at 1480, 1370, and 1120 cm À 1 , respectively. Compared to the FT-IR spectrum of the CO 2accumulated catalyst, there were no carbonate species on the surface of the catalyst after oxidative activation.…”

“…Methane can induce a strong greenhouse effect with a global warming potential 20 times higher than that of CO 2 . At present, methane emissions due to human activities mainly come from industrial processes, vehicles, and waste managements ,. To meet the strict emission regulations, efforts are required to be made in developing efficient and durable catalysts for reducing methane emissions.…”

“…[1] At present, methane emissions due to human activities mainly come from industrial processes, vehicles, and waste managements. [2,3] To meet the strict emission regulations, efforts are required to be made in developing efficient and durable catalysts for reducing methane emissions. Taking the natural gas-heavy-duty vehicles as an example, exhaust gases contain low-concentration unburned methane at low temperatures (< 550°C).…”

Fuel Switch to LNG in Heavy Truck Traffic

“…Even though reductions of said greenhouse gasses are significant, climate benefits may be Energies 2019, 12, 515 6 of 19 reduced or even delayed for decades due to loss of methane from gas supply chain. Methane impact on climate change is more than 25 times greater than same mass of CO 2 over a 100-year period [42,43]. Thus, switch to LNG trucks may have negative impact on climate for next 200 years, even though usage of natural gas in other sectors may be beneficial at all time frames [44].…”

“…losses would be around 1. 43 After calculating fuel costs per truck for several different fuel prices, five different price scenarios were created. In these scenarios, it is assumed that all 300,000 trucks in EU are LNG trucks.…”