Lastly, most cooling towers use fans to force air through the tower to maximize heat transfer. Natural convection towers are uncommon as they require very large volumes to allow the air to buoyantly circulate and are thus expensive. We only analyze forced-convection towers in this analysis and quantify the electricity cost (i.e. "parasitic power") they incur to cool the process fluid. The parasitic power is quantified in genGEO using the parasitic power fraction, , shown in Equation S30, which is the ratio of tower parasitic electric power, , to the tower thermal S.21 heat rejection, . This parasitic power fraction concept is adopted from Adams et al. ( ) and we use slightly different regression coefficients in this study. In genGEO, the cost of a cooling or condensing tower is determined by a two-step process: 1) finding the cost of a Baltimore Aircoil Company (BAC) cooling tower with a nominal cooling capacity of 1 MW th , and 2) up-scaling the cost to the cooling capacity required. This allows highfidelity data obtained from BAC to be used to estimate the cost and performance of much larger units. The physics of cooling and condensing towers is the same for any capacity.