Influence of low-temperature electrolyser design on economic and environmental potential of CO and HCOOH production: A techno-economic assessment

The electrochemical conversion of excess CO2 into valuable chemicals, such as carbon monoxide (CO) and formic acid (HCOOH) offers the possibility of combating climate change, while simultaneously providing sustainable raw materials for the chemical industry. The system design choice has large implications for the economic competitiveness of such processes. The impact of low-temperature electrolyser design on the economic potential of CO and HCOOH production was investigated alongside an environmental assessment of the required chemical plants. Six different cell architectures were analysed in a base and an optimistic case scenario with a target production of 75 and 100 tProduct/day, respectively, and a projected plant lifetime of 25 years. While none of the CO architectures managed to operate profitably in the base case, the modelling of both HCOOH architectures yielded a positive economic outcome. The CO producing systems showed an on average 22% greater performance improvement in the optimistic case, compared to HCOOH. The environmental potential to act as a carbon sink was determined through an analysis of the CO2 emissions due to heat and electricity demand as well as the CO2 utilisation of the systems. While HCOOH production requires clean electricity with maximum carbon intensities of 137 gCO2/kWh in the optimistic case, CO production only requires a maximum of 346 gCO2/kWh, which is well above the current EU electricity mix of 235 gCO2/kWh. © 2021 The Authors