Jurisdictions throughout the world are contemplating greenhouse gas (GHG) mitigation strategies that will enable meeting long-term GHG targets. Many jurisdictions are now focusing on the 2020-2050 timeframe. We conduct an inter-model comparison of nine California statewide energy models with GHG mitigation scenarios to 2050 to better understand common insights across models, ranges of intermediate GHG targets (i.e., for 2030), necessary technology deployment rates, and future modeling needs for the state. The models (not including the Wind-Water-Solar model) ; the transportation sector is decarbonized using a mix of energy efficiency gains and alternative-fueled vehicles; and bioenergy is directed almost exclusively towards the transportation sector, accounting for a maximum of 40 % of transportation energy by 2050. Models suggest that without new policies, emissions from nonenergy sectors and from high-global-warming-potential gases may alone exceed California's 2050 GHG goal. Finally, future modeling efforts should focus on the: economic impacts and logistical feasibility of given scenarios, interactive effects between two or more climate policies, role of uncertainty in the state's long-term energy planning, and identification of pathways that achieve the dual goals of criteria pollutant and GHG emission reduction.
Hydrogen fuel cells are an important part of a portfolio of strategies for reducing petroleum use and emissions from medium and heavy duty (MD and HD) vehicles; however, their deployment is very limited compared to other powertrains. This paper addresses gaseous hydrogen storage tank design and location on representative MD and HD vehicles. Storage design is based on vehicle size and occupation. The available storage space on representative vehicles is assessed and is used to estimate the weight and capacity of composite material-based compressed gaseous storage at 350 and 700 bar. Results demonstrate the technical feasibility of using hydrogen storage for fuel cell electric trucks (FCETs) across a wide range of the MD and HD vehicle market. This analysis is part of a longer-term project to understand which market segments provide the maximum economic impact and greenhouse gas reduction opportunities for FCETs.
Policymakers use incentive-based vehicle scrappage or "Cash-for-Clunker" programs to pursue a range of social and economic goals such as decreasing vehicular emissions, preventing vehicle abandonment, lowering consumer spending on gasoline, and stimulating new vehicle sales. However, there are no programs aimed solely at greenhouse gas (GHG) reduction. This study discusses design considerations for such a program. We evaluate past and present programs to show how regulatory elements in vehicle scrappage programs can be adjusted to maximize GHG savings. We show how fuel-economy based eligibility requirements are preferable to age-based requirements and how financial incentives can be properly aligned to balance program cost and participation rate. Finally, we present a program framework that, at minimum, ensures a Cashfor-Clunkers program offsets GHG emissions attributable to vehicle manufacturing and end-oflife disposal with use-phase emissions reductions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.