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Emerging technologies for climate-neutral urban areas

An Industrial Ecology perspective

Time: Tue 2021-05-11 15.00

Location: Videolänk https://kth-se.zoom.us/j/62314215036, Du som saknar dator /datorvana kontakta Kosta Wallin kosta.wallin@abe.kth.se / Use the e-mail address if you need technical assistance, Stockholm (English)

Subject area: Industrial Ecology

Doctoral student: Asterios Papageorgiou , Resurser, energi och infrastruktur

Opponent: Professor Ola Eriksson, University of Gävle

Supervisor: Docent Cecilia Sundberg, Resurser, energi och infrastruktur; Doctor Rajib Sinha, Hållbar utveckling, miljövetenskap och teknik; Docent Maria Malmström, Anläggning och miljö, Mark- och vattenteknik, Kemiteknik, Hållbar utveckling, miljövetenskap och teknik

Abstract

The ever-increasing concentration of human activity in urban areas induces environmental problems beyond their boundaries on scales ranging from local to regional to global, such as resource depletion, land degradation, air and water pollution and climate change. Human-induced climate change is widely acknowledged as one of the greatest sustainability challenges of the present century and it is inextricably linked to urbanization. As a response to climate change, urban areas around the world have committed to reach climate neutrality within the next decades. In this context, the deployment of new technologies can have a key role in achieving carbon neutrality in urban areas. As new technologies emerge, it is essential to assess their environmental performance considering the broader systems context in order to ensure that they can indeed contribute to achieving climate neutrality without compromising environmental sustainability.

This thesis aims is to provide insight on the environmental performance of emerging technologies that can be deployed in urban areas in order to contribute to achieving climate neutrality. The two technologies in focus are grid-connected solar microgrids and biochar-based systems for treatment of biomass waste and remediation of contaminated soil. The methods applied to conduct the environmental assessments and fulfil the aim of the thesis are: case studies, Life Cycle Assessment (LCA), Material and Energy Flow Analysis and Substance Flow Analysis. Moreover, as part of the research efforts, a spreadsheet model based on LCA data was developed.

The assessment of the solar microgrid highlighted the importance of using explicit spatial and temporal boundaries when analyzing the environmental performance of energy systems, as it can increase the accuracy of the results. It also revealed that the choice of modeling approach can influence the results of the assessment, which motivates the application of different methodological approaches. Within this context, the assessment showed that in a short-term perspective the integration of a grid-connected urban solar microgrid into the Swedish electricity grid would not contribute to climate change mitigation, as solar electricity from the microgrid would displace grid electricity with lower carbon intensity. The assessment also indicated that operational and structural changes in the microgrid could reduce its climate change impact, albeit not to the extent to generate GHG emission abatements.

The assessment of the biochar-based systems showed that these systems have many environmental benefits compared to incineration of waste and landfilling of contaminated soil. They have great potential to contribute to achieving climate neutrality, as they can provide net negative GHG emissions, owing mainly to carbon sequestration in the biochar. Between the two biochar-based systems, a system for on-site remediation can provide additional environmental benefits, as it can lead to more efficient use of resources. However, these systems also entail environmental trade-offs due to increased consumption of auxiliary electricity, while the extent of ecological and human health risks associated with the reuse of biochar-remediated soils is for the moment unknown.

urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-292648