Category: Scientific Theses

Master’s thesis: Social Marginal Abatement Cost of Negative Emissions: Incorporating Externalities into the Private Costs of Carbon Dioxide Removal

Anna Havukainen, University of Helsinki,

The objective of this thesis was to identify the Negative Emission Technologies and Practices (NETPs) that yield the lowest social costs, thereby providing insights into which NETPs should be prioritized for investments in CDR. This evaluation was conducted by developing a Social Marginal Abatement Cost Curve (SMACC) framework, to examine the potentials and social costs of various NETPs. 


PhD-thesis: Concentrating Alkalinity for Direct Air Capture of Carbon Dioxide: Using Osmotic Pressure for Concentration and Separation

Anatoly Rinberg, Harvard University,

First, the author proposes a new approach for removing atmospheric CO2, the alkalinity concentration swing (ACS), driven by concentrating and diluting aqueous alkaline solution, which increases and decreases the partial pressure of CO2 of the solution, respectively. Second, he improves on the ACS process by introducing a selectivity step, which separates bicarbonate ions from carbonate ions. A theoretical investigation reveals that bicarbonate-enrichment allows for reaching higher cycle capacity, higher CO2 partial pressure, and improved absorption rates. Third, nanofiltration is experimentally studied, and confirmed as a mechanism to enrich bicarbonate ions, reaching bicarbonate-carbonate selectivity factors above 30. Fourth, he experimentally demonstrates the ability to use reverse osmosis, a membrane-based separation process driven by applied pressure, as a method for concentrating alkalinity.


PhD-Thesis: Ocean Alcalinity Enhancement: Tool to Mitigate Climate Change

Jakob Bang Rønning, University of Southern Denmark,

This thesis explores the potential of ocean alkalinity enhancement as an ocean-based carbon dioxide removal method, specifically focusing on alkaline minerals for mineral-based OAE as novel avenues for climate change mitigation. As global decarbonization is obliged, integrating diverse CDR technologies is essential to effectively counter and reverse the ongoing trend of global CO2 emissions in the atmosphere. This thesis studied the nuanced aspects of mineral-based OAE, emphasizing the potential of alkaline minerals such as dolomite, limestone, and olivine. The study aims to examine their impact on seawater carbon chemistry and primary producers. 


Master thesis: Potential analysis of the integration of flexibly operated Direct Air Capture (DAC) plants in the heat and power system using the example of Hamburg

Moritz Rickert, Hamburg University of Applied Sciences,

For climate neutrality by 2045, Germany must compensate unavoidable residual greenhouse gas emissions by negative emission technologies such as direct air capture technology. This study explores the technical feasibility and economic viability of implementing flexibly operated DAC plants in Hamburg’s district heating system in 2045.


Licentiate thesis: Modeling the Potential for Carbon Removal in Agriculture: Integrating Farmer Perspectives

Andreas Rehn, Chalmers Universtiy of Technology

The overarching aim of this thesis is to provide insights into the dynamic processes governing SOC stocks and to identify viable paths for agricultural systems to contribute to climate change mitigation. By integrating current scientific knowledge of carbon sequestration in agriculture with feasible agricultural applications, this work proposes local realistic strategies for enhancing soil organic carbon and presents a quantitative assessment of their potential for CO2 removal.


PhD-Thesis: Promises and Pitfalls of Bioenergy with Carbon Capture and Storage: Actors’ Perspectives, Challenges, and Mitigation Deterrence in Sweden

Emily Rodriguez, Linköping University, DOI: 10.3384/9789180754873

The aim of this thesis is to examine challenges for the implementation of BECCS in Sweden to contribute to sustainability transitions, and to analyze the prospect for deploying BECCS through the lens of mitigation deterrence. This lens is a way to study risks of foregone emissions, overshoots, and rebound effects when relying on a future carbon removal method such as BECCS. This thesis studies how BECCS is socially constructed by key actors in Sweden by analyzing perspectives held by companies, civil servants, political parties, and other key actors, through interviews and focus groups. This study also analyzes how plans to include BECCS impact net-zero strategies in Stockholm, the first city to have a pilot and demonstration facility for BECCS in Europe.


PhD-Thesis: Quantification of Pedogenic Carbonate Formed Due to Enhanced Weathering in Agricultural Soil and Subsoil

Reza Khalidy, University of Guelph,

The introduction of powdered Ca and Mg-rich silicate minerals to soil, called enhanced rock weathering, has been found effective in stabilizing atmospheric carbon in the form of solid carbonates. Among different minerals, wollastonite is recognized as the primary candidate for this process due to its high reactivity, simple chemical structure, and known agronomic benefits. The current doctoral thesis aims to investigate the fate of wollastonite over vertical soil profile and assess the migration of weathering products over short-term and long-term time scales. To track migration of weathering products (e.g., pedogenic carbonate and bicarbonates), a laboratory-scaled soil column experiment was conducted over a short term. Furthermore, field-scale experimental trials were carried out to assess the impact of wollastonite ore dosage and soil properties on the formation and downward movement of released metals and carbonates.


Senior-Thesis: Public Perception’s Role in Carbon Removal at Scale: The Importance of Public Opinion on Barriers to Implementation of CDR

Ben Evanson, University of Texas at Austin,

The CDR industry will need to overcome six primary barriers: Biophysical Constraints, Research and Modeling, Governance, Funding Mechanisms, Social Acceptability, and Industry Development. Lacking thus far in literature, this thesis explores what role Social Acceptability plays within each of the other established barriers to scaling. This thesis analyses these barriers through the lens of a social license to operate (SLO), building off related industries’ successes and failures in achieving such an SLO. We identify four unique communities whose acceptance of the carbon removal industry will be important to its ability to scale at speed and to a high capacity, political communities, markets, general publics, and local communities.


Master-thesis: Exploring support alternatives within the European Union policy framework for technological carbon dioxide removal and biogenic carbon sequestration: a present-day assessment

Ulriikka Aarnio, Tampere University of Applied Sciences,

This thesis studies the landscape of carbon dioxide removal and sequestration (CDRS) support methods within the European Union (EU) with a primary focus on their efficacy in achieving net negative emissions.