Project Summary
Problem Statement: The recent commercialization of advanced CNG engines for medium-duty vehicles (MDV) and heavy-duty vehicles (HDV) that can dramatically reduce emissions of NOx relative to baseline technologies has garnered significant interest due to the potential for air quality benefits.
Furthermore, the co‐utilization of renewable natural gas (RNG) from pathways including biomass/biogas and power‐to‐gas can achieve deep reductions in greenhouse gas (GHG) emissions relative to both diesel and clean natural gas (CNG). However, the regional air quality and GHG impacts of large‐scale deployment are currently unclear and require quantification, including both primary and secondary pollutants including ground-level ozone and PM2.5. More information is needed regarding the RNG production pathways that provide the greatest GHG reductions and regional air quality improvements.
Proposal: The goal of the proposed research is to assess the emissions and air quality impacts of transitions to advanced low‐NOx CNG engines in MDV and HDV applications in California with a particular emphasis on renewable natural gas (RNG) as a fueling pathway. Objectives include:
1. Developing a set of future scenarios for deployment of advanced low‐NOx CNG engines in various vehicle classes comprising the MDV and HDV sectors in California
2. Leveraging prior research of biogas and biomass resources in California to develop scenarios of potential infrastructure and resource pathways to support RNG vehicle fueling
3. Leveraging prior research of wind and solar resources in California to develop scenarios of potential infrastructure and resource pathways to support power‐to‐gas RNG vehicle fueling
4. Quantifying changes in lifecycle GHG emissions from baseline for scenarios and compare and contrast to identify strategies that maximize reductions from California’s RNG resources
5. Applying quantified emission changes via an emissions processing model (SMOKE), and producing spatially and temporally resolved emission fields
6. Conducting simulations of atmospheric chemistry and transport via a photochemical AQ model (CMAQ) to quantify and spatially resolve impacts on primary and secondary pollutants including ozone and PM2.5
7.
Expected Impact and Benefits: This research will directly contribute to the goals for CARB’s Mobile Source Strategy including meeting California and Federal Clean Air Act standards, reducing health risk, and meeting GHG reduction goals (AB 32 and SB 375) by providing insight into the development and implementation of strategies to reduce emissions from medium‐ and heavy‐duty vehicles. Additionally, results will support CARB’s efforts to support disadvantaged communities (SB 535 and SB 350). Results from this work will build a scientific foundation supporting the development of effective emission mitigation strategies supporting numerous State efforts, including the Sustainable Freight Action Plan, Scoping Plan measures, and to the Short‐Lived Climate Pollutant Strategy. This research also leverages significant investment by the Department of Energy and the California Energy Commission in modeling tools developed by the Advanced Power and Energy Program that enable these air quality and GHG analyses.
