Abstract:

This assessment analyzes the implications of a growing natural gas vehicle fleet on the emission benefits of the U.S. heavy-duty vehicle Phase 2. The approach includes a synthesis of data from leading sources on upstream emissions, vehicle emissions, and efficiency technology. The assessment involves in part stock turnover model analysis of the U.S. medium- and heavy-duty vehicle fleet. The findings of the report indicate that the treatment of natural gas emissions in the heavy-duty vehicle rulemaking could have substantial implications for c. The analytical results are presented in terms of the total potential carbon dioxide equivalent (CO2e) emissions across scenarios with varying vehicle efficiency, methane emissions, and natural gas penetration among the fleet. This paper presents GHG emissions scenarios under different assumptions about natural gas vehicles’ market penetration, methane leakage, methane global warming potential, and efficiency. Then, the paper discusses critical areas that may be addressed and policy-related approaches to the regulatory framework that will allow the natural gas vehicle industry to get a strong footing in the heavy-duty vehicle market while simultaneously safeguarding against any negative climate impacts resulting from the widespread adoption of natural gas vehicles. This study focuses on the greenhouse gas emission implications of an increasing population of natural gas trucks in the U.S. fleet, but of course there are other considerations related to natural gas–fueled vehicles and policy.