Abstract
Fossil fuels in transportation are a significant source of local emissions in and around cities; thus, decarbonising transportation can reduce both greenhouse gases (GHGs) and air pollutants (APs). However, the degree of these reductions depends on what replaces fossil fuels. Today, GHG and AP mitigation strategies are typically ‘decoupled’ as they have different motivations and responsibilities. This study investigates the ancillary benefits on (a) APs if the transport sector is decarbonised, and (b) GHGs if APs are drastically cut and (c) the possible co-benefits from targeting APs and GHGs in parallel, using an energy-system optimisation model with a detailed and consistent representation of technology and fuel choices. While biofuels are the most cost-efficient option for meeting ambitious climate-change-mitigation targets, they have a very limited effect on reducing APs. Single-handed deep cuts in APs require a shift to zero-emission battery electric and hydrogen fuel cell vehicles (BEVs, HFCVs), which can result in significant upstream GHG emissions from electricity and hydrogen production. BEVs powered by ‘green’ electricity are identified as the most cost-efficient option for substantially cutting both GHGs and APs. A firm understanding of these empirical relationships is needed to support comprehensive mitigation strategies that tackle the range of sustainability challenges facing cities.
Highlights
Radical shifts in the current fossil-based energy system are needed to reduce greenhouse gas (GHG) emissions and improve local air quality
With the modelling approach and assumptions used in this study, shifting from fossil fuels to biofuels in conventional vehicles is the least-cost pathway for achieving an ambitious CO2 mitigation target in the transport sector, but this produces very limited, or even negative, ancillary benefits for local air pollutants (APs) such as particulate matter (PM) and nitrogen oxides (NOX)
While deep cuts in APs require a shift to zero-emission vehicles such as BEVs and HFCVs, which will reduce tailpipe CO2 emissions, it may entail significant upstream CO2 emissions from electricity or H2 production
Summary
Radical shifts in the current fossil-based energy system are needed to reduce greenhouse gas (GHG) emissions and improve local air quality. Cities collectively account for more than three quarters of the total global final-energy use and generate three quarters of total global GHG emissions [1]. Since most transportation fuels have fossil sources, they generate significant emissions of both carbon dioxide (CO2) [4] and air pollutants (APs) [5]. With this close connection between CO2 and APs, there is broad scientific consensus that reducing fossil fuel combustion to mitigate climate change could improve local air quality [6]. Battery electric and hydrogen fuel cell vehicles (BEVs and HFCVs, respectively) can completely eliminate local emissions, their total contribution to mitigating climate change is determined by upstream factors such as the feedstock of and specific production pathways for electricity and hydrogen (H2) [11,12,13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
