Document Type

Working Paper

Date of this Version



Power-to-gas technologies, which produce gaseous fuels using electricity, are emerging as a green energy source and for renewable electricity storage and distribution. This project proposes a power-to-methane process using a biologically sourced Ru-pBN catalyst and carbon dioxide emissions from a co-located ethanol plant. The carbon dioxide is reacted with green hydrogen from electrolysis to generate methane at 500 psig to be sold and delivered through the pipeline. This process converts 9,100 kg/hr of CO2 emissions into 3,400 kg/hr of natural gas via the Sabatier reaction using a tubular flow reactor at 400oC and 3.1 bar. Various separation processes were included in the design to recycle unreacted carbon dioxide in order to minimize emissions as well as produce methane at 97.8 mol% purity, equating to a higher heating value (HHV) of 984 Btu/scf. The production of green hydrogen qualifies this project for the Clean Hydrogen Production Tax Credit §45V at a rate of $3/kg hydrogen produced.

The base-case scenario for this project achieves an internal rate of return (IRR) of 17.3% with a net present value (NPV) of $5,177,000 and a return on investment (ROI) of 15.0% in the third year of production. If the project is able to be powered entirely by surplus electricity that would have otherwise not been generated (or curtailed), an IRR of 42.2% is possible. However, if the proposed plant is not powered by any surplus electricity or if it does not qualify for the hydrogen tax credit, this power-to-methane process is not profitable. In the future, the process will likely become economically viable without the reliance on government subsidies as further improvements are made in the cost of producing hydrogen via electrolysis and carbon dioxide sequestration.



Date Posted:25 May 2023