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The development of carbon dioxide utilization (CDU) technologies is heavily influenced by policy priorities such as access to renewable energy resources and the country's economic structure. At the same time, most conversion-based CDU technologies are early-stage technologies characterized by significant uncertainties due to a nascent knowledgebase and limited available data. Consequently, identifying major sustainability hurdles and hotspots is crucial in ensuring effective allocations of R&D resources in technology upgrading and upscaling. In this study, we formulate the task of identifying sustainability hurdles as assessing and ranking key sources of risk that influence whether a given CDU technology is sustainable or not. To this end, we propose a novel methodology for risk-based uncertainty assessment through classification based on stakeholder-set sustainability decision rules. Risk is subsequently quantified by comparing the class likelihoods. For multiple sustainability criteria scenarios, additional stakeholder input in the form of joint conditional probabilities is implemented in the decision rules. We demonstrate the methodology by applying it to the CO2 hydrogenation to formic acid process employing heterogeneous Ru/bpyTN-30-CTF catalysts, being developed as part of the ongoing Carbon-to-X R&D initiative in South Korea. The proposed methodology is most applicable to CDU technologies with TRLs between 3 and 5 in which the core utilization concepts have already been experimentally validated and the conceptual design process has started. [ABSTRACT FROM AUTHOR]

Hydrogen has become widely recognized as a game changer in the era of climate change and stringent carbon reduction targets. For countries with inadequate distributions of renewable energy, a comprehensive evaluation of potential national and international routes for green hydrogen supply networks is imperative. This study examines the economic and environmental aspects of green hydrogen supply routes for hydrogen refueling stations (HRS) in the Republic of Korea. Three supply routes are evaluated in this work: Case (1) hydrogen production via catalytic cracking of imported green ammonia, Case (2) domestic green hydrogen production at a centralized location in Korea, and Case (3) on-site hydrogen production via water electrolysis at HRS powered by solar electricity from the city grid. The levelized costs of hydrogen (LCOH) were calculated as $9.74, $17.32, and $13.97 per kg for Cases 1, 2, and 3, respectively. The results of sensitivity analysis indicate that the capital cost related to the provision of green ammonia (Case 1), solar electricity, and the electrolyzer were the main contributors to LCOH. Based on projected cost reductions, LCOHs would decrease to $8, $11.76, and $10 per kg for Cases 1, 2, and 3, respectively. Life cycle assessment (LCA) shows that Case 3 is the favored environmental alternative owing to reductions in greenhouse gas (GHG) emissions of 44% and 12% compared with Cases 1 and 2, respectively. The results of LCA sensitivity analysis depict that by 2030, with the increase in the distance of transportation, Case 2 can show the highest increase of 58% for GHG emissions, while an increase of about 8% can be expected for Case 1. However, in Case 3, further work on policy design and infrastructure development is required to make solar electricity provisions in the city grid profitable. [ABSTRACT FROM AUTHOR]

Carbon capture and utilization (CCU) technology provides a promising approach for minimizing greenhouse gas (GHG) emissions and fossil resource depletion. Formic acid (FA) is a valuable chemical that can be produced using various CCU technologies; so it is necessary to explore the environmental impacts of potential FA production technologies. This study quantified the two major environmental impacts (climate change and fossil depletion) for two CCU strategies (catalytic and electrocatalytic CO2-based FA production) and compared them with the conventional strategy. Life cycle assessments were conducted for the integrated conversion and separation processes carried out in the Yeosu Industrial Complex in the Republic of Korea based on the literature data and simulation study. The results showed that the CCU strategies could reduce GHG emissions by 97%–132% (1.43–1.95 kg of CO2 eq. per kg of pure FA) and save 69%–94% (0.56–0.78 kg oil eq. per kg of pure FA) of fossil resources compared with the conventional strategy. The major environmental drivers were identified for all strategies, and it was clear that the utility input was a major contributor to the environmental burden in all strategies. Scenarios in which the utility source and raw material supply were varied were analyzed to determine how to effectively reduce the environmental impact of CO2-based FA production. Finally, several implications were proposed for the development of an environmentally feasible electrocatalytic CO2-based FA production strategy: (1) improving the energy efficiency in reaction and separation and (2) introducing renewable electricity sources. [ABSTRACT FROM AUTHOR]

Formic acid (FA, HCOOH) using carbon dioxide (CO2) as a feedstock is sufficient to be synthesized on an industrial scale because it can be used as a carrier of hydrogen (H2) and as a precursor chemical in many chemical processes. Utilizing CO2 as an alternative carbon feedstock for FA production comes from reduction methods for greenhouse gas emission and fossil resource depletion. This study compares life cycle assessments (LCAs) to produce FA using CO obtained from fossil fuels (the conventional method), and using CO2 obtained using the carbon capture and utilization (CCU) method. The simulation compares supply energy (heat, electricity), and feedstock usage (CO, CO2, H2), and environmental impacts of FA production by the two processes in the Jeollanam-do industrial sector of Korea. The largest contributors to climate change (CC) were CO (71%) and heat (24%) in the fossil-based conventional process and H2 (76%) and electricity (9%) in the CCU process. The largest contributors to fossil resource depletion (FD) were CO (79%) and heat (18%) in the fossil-based conventional process and H2 (70%) and electricity (18%) in the CCU process. A case study showed that the lowest environmental impact was obtained using a combination of heat generation by burning wood chip, and electricity generation using hydropower. These results suggest that the use of captured CO2 for FA production can mitigate greenhouse gas emissions and fossil resource depletion. [ABSTRACT FROM AUTHOR]