While most sources describe O&M costs as O&M cost fractions, a few (i.e. Sanyal (2004), GETEM, and GEOPHIRES) provide O&M costs as a function of capacity. We discovered that despite the use of non-linear relations by these sources to estimate O&M cost as a function of capacity, when the O&M cost is normalized, the O&M cost fraction is relatively constant. This is shown by the narrow error bars of Sanyal (2004) and GETEM in Figure . Thus, we find that reporting O&M cost as an O&M cost fraction still provides the same sensitivity to capacity as more complex models. Lastly, the large O&M cost fraction variation of GEOPHIRES is due to an incomplete characterization of the GETEM model upon which it is based and we therefore do not weight it heavily. The variability in O&M cost is similar across all sources and technologies in Figure . For instance, the non-geothermal cost estimates have a similar variability in cost fraction as the geothermal cost estimates. More detailed data from electricity operators would be needed to distinguish geothermal costs from other types of power cycles. However, but based on the data found in our review, we can't make meaningful comparisons between geothermal and nongeothermal power plants and thus assume the O&M cost fraction is constant across all technologies.