Skip to main content

Conversion Pathways

Carbon dioxide (CO2) reduction pathways—either direct or indirect—can be divided up by the conversion technology and the method for electricity utilization.

Direct Pathways

Direct pathways involve electrons directly in the chemical reduction process.

Microbial Electrosynthesis

Micro-organism enabled low-temperature electrocatalytic reduction.

High-Temperature Electrolysis

High-temperature electrocatalytic reduction in a ceramic membrane reactor.

Low-Temperature Electrolysis

Low-temperature electrocatalytic reduction in polymer electrolyte membrane reactors.

Indirect Pathways

Indirect pathways utilize intermediate electron carriers, such as hydrogen.

Thermochemical Conversion

Catalytic hydrogenation of carbon dioxide using heat and pressure.

Biological Conversion

Microbial fermentation of carbon dioxide and hydrogen.

Summary Table

 Projected Costs (2016$)
PathwayProduct2014–2018 Market Price Range (2016$/kg)CurrentFutureTheoretical

Low-Temperature Electrolysis

Carbon Monoxide0.17–0.261.550.230.07
Formic Acid0.66–0.67*1.360.230.05
Oxalic Acid1.40**2.230.330.03
Ethylene0.38–1.296.391.200.42
Ethanol0.42–0.726.070.740.30
Microbial ElectrosynthesisMethane0.13–0.23107.81.900.76
Acetic Acid0.50–0.71 5.320.570.22
Formic Acid0.66–0.67*26.420.290.21
Ethanol0.42–0.72441.011.100.54
High-Temperature ElectrolysisCarbon Monoxide0.17–0.260.380.150.05
Methane0.13–0.2311.150.770.36
Biological ConversionMethane0.13–0.232.221.040.64
Acetic Acid0.50–0.710.950.340.21
Ethanol0.42–0.721.270.640.39
Polyhydroxybutyrate2.40–3.30***1.360.640.37
Thermochemical ConversionCarbon Monoxide0.17–0.260.450.250.16
Methane0.13–0.23 2.281.080.68
Dimethyl Ether0.49–0.721.890.870.58
Methanol0.25–0.481.660.800.52
Fischer-Tropsch Liquids2.14–3.414.521.310.81

*Data only for 2014 and 2016
**Data only for 2017
***Data from 2017, includes all PHAs

Publications 

For more analysis and discussion on these CO2 conversion pathways and their products, see these accompanying publications.

The Economic Outlook for Converting CO2 and Electrons to Molecules, Energy & Environmental Science (2021)

Transforming the Carbon Economy: Challenges and Opportunities in the Convergence of Low-Cost Electricity and CO2 Utilization, Energy & Environmental Science (2019)


Share

Last Updated April 21, 2025