Transportation and solar-aided utilization of CO2: Technoeconomic analysis of spanning routes of CO2 conversion to solar fuels

Abstract

The present study provides a viable route to solar syngas production and conversion to fine chemicals using renewable energy sources and rendering CO2 a valuable reactant instead of a waste. It uses existing facilities and on-going breakthrough technological advancements from CO2 transportation to H2O/CO2 solar co-splitting for syngas formation to further conversion to either methanol or Fischer-Tropsch (FT) products. A full scale simulation of the overall chemical process is established, considering its subsections with respect to all relevant cost elements and operating expenses using appropriate cost correlations. Eight spanning routes of the CO2 superstructure are assessed for a real case of transporting compressed pure or mixtures of CO2 with a 130 kg/s capacity over a distance of 120 km from a power plant in Ptolemaida, Greece, operating with either natural gas or coal, and combining with water from an existing wastewater treatment facility in Thessaloniki, Greece. It is estimated that the choice of producing methanol requires an investment of ˜€7B and ˜€430 M/y to operate, while for FT-related plants it would cost >€3B to build and ˜€190 M/y to operate. Applying a standard feed-in tariff (FIT) value in terms of subsidization of the energy consumed by renewable sources boosts the expenditure resulting for the best case to a yearly net profit of ˜€500 M or ˜€100 M, for methanol or FT products, respectively. Other scenarios are also considered, including the best spanning route for the minimum FIT revenues by the break-even method, or the required carbon price without any subsidization of the proposed schemes.