Ex-ante techno-economic analysis: An ocean iron fertilization case study

The study provides an updated comprehensive framework for conducting techno-economic assessment (TEA) of novel carbon dioxide removal (CDR) approaches as there are limited comprehensive comparative studies in this space. The framework is applied to 2 scenarios of a nature-based CDR solution, known as ocean iron fertilization, in the Southern and Atlantic Oceans. The study investigates whether cost elements such as administrative and support labor are accurately included in standard methodologies and proposes solutions on how to characterize prospective (future) cost elements and uncertainty in such models of novel CDR approaches. A local sensitivity analysis on the major model inputs indicates that oceanographic parameters, such as the export efficiency of carbon biomass to the deep ocean, have a greater impact on the levelized cost of carbon removal (LCOC) compared to engineering parameters, such as the cost of equipment or materials. Yet, large capital engineering expenditures (~$40-200M) are also found to have a high impact on the levelized cost. The outcomes of the model provide suggestions on how aspects of other fields such as monitoring, reporting, and verification and oceanographic science need to be developed before cost estimate ranges can be further constrained. The effect of these high impact parameters on the LCOC is shown by an estimated range of between $30 /tCO₂ to $ 393,571 /tCO₂ for best- and worst-case scenarios when the values for monitoring, reporting and verification (MRV) processes, export efficiency, net increase in primary production, and ventilation losses of CO₂ to the atmosphere, are varied. The study provides a framework that can be used to create consistent and comprehensive economic comparisons for carbon dioxide removal technologies, which work within natural processes to combat climate change. These comparisons aim to allow companies and decision makers to make informed decisions and drive funding in in the CDR space towards solutions with maximum CO2 removal impact, at minimum cost and environmental impact. Without comprehensive economic estimations, research into the wider impacts, including environmental and social, will be limited.