Determining Air Quality and Greenhouse Gas Impacts of Hydrogen Infrastructure and Fuel Cell Vehicles

Abstract

Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 µg/m 3 in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

Air quality impacts of fuel cell electric hydrogen vehicles with high levels of renewable power generation

“…Replacing the current on-road LDV fleet with FCEVs would reduce net GHG emissions in the U.S [25,26] and CA [27] with similar findings reported for pollutant emissions at various scales [28e30]. In particular, FCEVs supplied with hydrogen produced via renewably powered electrolysis can achieve large-scale reductions in total emissions from transportation [31].…”

“…While studies have shown that FCEV driven reductions in direct emissions result in improvements in secondary air pollutants, including ground-level ozone and PM 2.5 [37,38], the body of available literature quantifying impacts on secondary air pollutants is limited. Use of a novel methodology for future hydrogen infrastructure development in the South Coast Air Basin (SoCAB) of CA reported substantial reductions emissions including NO x for the majority of Cases [30] translating to significant AQ improvements (e.g., reductions in peak 8-haveraged ozone and 24-h-averaged PM 2.5 concentrations) [27]. However, existing studies were spatially restricted to select regions of CA (e.g., the SoCAB, Sacramento) or the entire U.S., and assume FCEV penetration is universal throughout the study domain.…”

Projecting full build-out environmental impacts and roll-out strategies associated with viable hydrogen fueling infrastructure strategies

“…To address the need for a comprehensive and fully integrated planning methodology, the Spatially and Temporally Resolved Energy and Environment Tool (STREET) was developed at the University of California, Irvine (UCI) to establish, then quantify and assess the full build-out and roll-out impacts of alternative transportation fuels through a comprehensive and integrated analysis that operates at a high level of spatial and temporal detail [10,11]. In particular, STREET provides the capability to:…”

“…Determine infrastructure needs and roll-out strategies for light-duty vehicle hydrogen fueling in a local community [10], and 2. Analyze the long-term environmental impacts (e.g., GHG emissions, air pollutant emissions, and air quality) of fully built-out hydrogen infrastructure scenarios [11].…”

“…The scenarios are developed with spatial and temporal detail by utilizing GIS data and the Preferred Combination Assessment (PCA) Model (a fuel supply chain impact assessment model) [14], both integral components of STREET. Other attributes of STREET are then employed to provide, for each scenario, an assessment of the future year air pollutant emissions and air quality (ozone and PM 2.5 ) impacts, greenhouse gas reduction, energy requirements, petroleum consumption, and water use [11].…”