As distributed generation continues its rapid expansion, these new resources will have an increasingly larger role. This analysis focuses on two prototypical investor-owned utilities, one in the southwest and one in the northeast. For each utility, this study models the potential impacts of PV over a 20-year period, estimating changes to utility costs, revenues, average rates, and utility shareholder earnings and return-on-equity (ROE). The base case analyses were performed with total penetration of customer-sited PV rising over time to stipulated levels ranging from 2.5% to 10% of total retail sales (compared to current penetration levels of 0.2% for the US as a whole and of roughly 2% for utilities with the highest penetrations, excluding Hawaii).