Analyzing the Prospects of Electroreduction of Carbon Dioxide to Value-Added Chemicals

Abstract

Increasing evidence suggests that the unwanted effects of climate change, including global warming, rising sea levels, and erratic weather patterns are the result of the increasing concentration of carbon dioxide (CO2) and other greenhouse gasses in the atmosphere. Further development and integration of renewable but intermittent energy sources such as solar and wind, as well as enhancing energy efficiency in buildings and transportation applications will be critical to significantly reduce global CO2 emissions. An alternative strategy to reduce CO2 emissions is the capture and subsequent electrochemical reduction of CO2 into useful chemicals such as formic acid, carbon monoxide (CO), hydrocarbons, or alcohols. This approach has the additional advantage that it can enhance the utilization of renewable energy that is produced in excess of grid demand (too much solar or wind energy production) and currently wasted. Multiple research efforts over the last decade have developed increasingly better cathode catalyst for the efficient electrochemical reduction of CO2 to formic acid, CO, and other products. At the same time progress has been made on anode catalysts (typically for the oxygen evolution reaction), gas diffusion electrodes suitable for CO2 electrolysis cells, and on the optimization of electrolysis operating conditions. Despite this progress, it is still unclear whether this emerging electrochemical technology has the potential to achieve a net reduction in CO2 emissions and is economically feasible. We developed a gross-margin model for a first order estimate of the economic viability of CO2 electrolysis. Second, in a collaborative effort, we performed a techno-economic analysis of a process that starts with the flue gas from a 0.5 MW power plant, captures the CO2, converts that CO2 into CO, which then in combination with hydrogen from a water electrolyzer is converted into liquid fuels via the Fischer Tropsch process. The results of these models with respect to economic viability and their ability to reduce greenhouse gas emissions will be presented.