Techno-economic assessment of a process to remove CO2 from the atmosphere

According to the latest IPCC reports, Carbon Dioxide Removal (CDR) technologies are required to limit global warming to “well below 2 °C”, as the objective of the Paris Agree ment. The present PhD thesis studies a CRD process developed in the framework of the Desarc-Maresanus research project, a combination of bioenergy and carbon capture and storage and ocean liming. A techno-economic analysis has been developed, assessing costs and CO2 penalty of the process in four different contexts (Brazil, China, Netherlands, and United States). An uncertain analysis based on the Monte Carlo method implemented in the program MATLAB has been done, using 11 varying parameters. The total cost of CO2 removal is assessed between 45 and 180 USD/tonCO2, a range similar to other assess ments of CO2 removal cost available in the literature. The countries where the cost is higher are the Netherlands and USA, because of higher limestone cost, biomass cost, and storage and transportation of CO2 cost. Since the capture and storage of CO2 emissions generated from the calcination of limestone is an essential point for a convenient CO2 balance of the process, an analysis of different types of storage available has been realized with different methodologies. For the traditional Carbon Capture and Storage (CCS), already at a high stage of development, a detailed literature review of the cost has been done considering 762 papers published in the scientific literature from 2018 to 2020. The cost of carbon avoided (the extra cost for the plant to do the capture and storage of a certain amount of CO2) that has a range from 50 to 100 USD/tonCO2, which is competitive with the current EU-ETS Carbon Prices, around 70- 90 €/tonCO2. Since the development of the traditional geological storage faces many diffi culties, the PhD thesis has evaluated an alternative CO2 storage method proposed in the literature, the Buffered Accelerated Weathering of Limestone (BAWL), that allow the storage of carbon in the form of bicarbonate in the deep ocean. The cost of CO2 storage with BAWL is assessed in the range 100-450 €/tonCO2 for an Italian location, including the cost of CO2 capture from a steam methane reforming flue gas. The uncertainty analysis based on Monte Carlo method shows that the most relevant parameters are pipeline cost, electricity cost and limestone cost. Although further research is needed to evaluate all the techno-eco nomic and environmental aspects of the CDR process and CO2 storage option considered, the present work provides information that could be of interest for the analysis of the role of CDR technologies in climate mitigation strategies.