Financial Impacts of Net-Metered PV on Utilities and Ratepayers: A Scoping Study of Two Prototypical U.S. Utilities

The analysis relies upon a pro-forma utility financial model that Lawrence Berkeley National Laboratory previously developed and deployed for the purpose of analyzing the utility shareholder and ratepayer impacts of utility-sponsored energy efficiency programs.  Using this model for the present study, we quantify the impacts of customer-sited PV for two prototypical investor-owned utilities: a vertically integrated utility located in the southwest (SW) and a wires-only utility and default service supplier located in the northeast (NE).  For each utility, we model the impacts of customer-sited PV over a 20-year period, estimating changes to utility costs, revenues, average rates, and utility shareholder earnings and return-on-equity (ROE).

These impacts were first assessed under a set of base-case assumptions related to each utility’s regulatory and operating environment, in order to establish a reference point against which sensitivities and potential mitigation strategies could be measured.  The base-case analyses were performed with PV penetration levels ranging from 2.5% to 10% of total retail sales (compared to current penetration levels of 1-2% in a number of the larger state solar markets and to the U.S. average of 0.2%).