The coal flow rate for the calcium looping model is misleading in the current interface. "Coal" on the Mass In/Out result screen and on the fuel diagram only includes the primary fuel, and the only auxiliary fuel shown is gas. The auxiliary coal used by the calcium looping model is not currently shown in these places, so with the additional net output, it looks like you're using less coal than you really are. We will correct this in the next release. For now, if you look at the Overall Plant Performance result screen, Auxiliary Fuel Input includes auxiliary coal.
Regarding the magnitude of the increase in net output, the original calcium looping model is fairly old (2012), and we do not have any funding to update it, so it will unfortunately have to stay as it is. (The magnitude was noted at the time the model was written, and the author stated that it was consistent with the data he had, so we presume this is the result of what is now an older configuration rather than a bug.) The technical documentation ("IECM Technical Documentation: Calcium Looping Cycle for Post-Combustion CO2 Capture", available in the Publications section of our website,
iecm-online.com) gives a lot of detail as to the equations used and the assumptions made. Sorry we couldn't be of more help here.