Greenhouse Gas Emissions, Energy Efficiency, and Cost of Synthetic Fuel Production Using Electrochemical CO2 Conversion and the Fischer-Tropsch Process

This study seeks to explore whether electrochemical reduction of CO2 (using current US average and future low carbon electricity) will become a viable route for the reuse of CO2 for producing synthetic fuel. This paper presents the results of a technical and economic analysis conducted for a pathway that converts CO2 released from fossil fuel-burning power plants to diesel fuel via electrochemical reduction of CO2 to CO and the Fischer-Tropsch process. Currently achievable performance levels for CO2 electrolyzers and the Fischer Tropsch process were used to compute key metrics, including (i) cost of the synthetic fuel, (ii) well-to-gate CO2 emissions, and (iii) overall energy efficiency. An engineering and economic model framework was developed for the investigation. The discounted cash flow analysis method was employed to calculate the cost of diesel fuel using a 500 MW power plant as the CO2 source. The model takes into account capital expenditures as well as operating costs for the reactors and auxiliaries. The final cost varies from 3.80 to 9.20 dollars per gallon in 2010 US dollars depending on the projected level of technology achieved. The WTG CO2 emissions vary from 180% (nearly twice) to a reduction of 75% compared to that of the business as usual scenario without carbon sequestration. The well-to-gate energy efficiency varies from 41 to 65%.