Overall, the deviations between genGEO, GETEM, and GEOPHIRES, and the variability across GETEM results, cannot be further explained. In contrast, genGEO results can be dissected to a first-principles of thermodynamics level of understanding. For example, Figure suggests that different secondary working fluids can change the specific capital cost of the surface plant by up to ~5%, so it is possible that some of the differences between GETEM and GEOPHIRES could be due to using different secondary working fluids.