The results presented above consider reference case input values. In order to incorporate uncertainty and evaluate sensitivity to individual model inputs, a 10,000 trial Monte Carlo simulation was conducted. NPVs for each of the five cases were defined as outputs for sensitivity analysis, and Fig. 6 shows the range of results of each given ±20% ranges for selected inputs. Uncertainty ranges were defined where information was available for specific inputs. The frequency distributions below provide a glimpse of how certain the NPV results are. For example, the off-grid scenarios consistently show negative NPV values, whereas the grid-tied PV-only scenario could show negative or positive NPV values, depending on inputs.