From the journal article, re: energy extraction from coal: "The thermodynamic enthalpy available per CO2 emitted from carbon combustion (−394 kJ/mole) is less

From the journal article, re: energy extraction from coal: "The thermodynamic enthalpy available per CO2 emitted from carbon combustion (−394 kJ/mole) is less than that from methane (−890 kJ/mole) combustion. Coal, compared to natural gas, combustion will generate less excess heat per transformable CO2 to drive CNF [carbon nanofiber] and CNT [copper nanotube] production product is retained within the system at (the electrolysis chamber temperature of) 750 °C, and hence under normal circumstances while a CC [combined-cycle natural gas] CNF plant can co-produce electricity and CNFs, a coal CNF plant will produce only value-added carbon nanotubes, and not surplus electricity." Annotations in brackets are mine.