Beyond Net Metering: Designing a Policy Portfolio for Measuring and Realizing the Value of Distributed Solar and Storage in Washington

In 1998, Washington made a simple promise to residents who installed solar panels: electricity they sent to the grid would be credited at the full retail rate. Net energy metering helped a new technology gain a foothold. That period is ending. Several Washington utilities have reached their statutory enrollment thresholds, and the June 30, 2029, deadline is approaching. Meanwhile, the questions have grown more complicated. Solar is now paired with battery storage more often, electricity demand in the Northwest is rising, and the state has committed to a clean electricity system under the Clean Energy Transformation Act.

In 2024, the Legislature asked the Washington State Academy of Sciences to look ahead: to identify ways to value distributed solar and storage and to examine how policy can realize them. This report completes the second phase of that work. It builds on the Phase 1 interim report delivered in June 2025.

The committee chose not to try to produce a single number for, or a single procedure to calculate, the value of rooftop solar. Instead, the report looks at how four policy mechanisms realize a representative set of benefits and costs, and how each one, retail rate design, grid services tariffs, utility procurement, and deployment incentives, affects different groups of customers. Three findings stand out. Pairing solar with storage matters more for benefit realization than any other single factor. No single mechanism captures the full range of value, so the mechanisms are best evaluated as a portfolio. And equity outcomes depend on mechanism design choices rather than on the technology itself.

The report also identifies important knowledge gaps. For several factors, including some of particular importance to Washington such as reducing hydropower ramping, the requisite data for analysis are thin or not specific to Washington. The report identifies these gaps so that future quantitative work can address them.

I am grateful to my colleagues on the Oversight Committee, who brought expertise in power systems, economics, regulation, and equity, and who gave their time and candor generously. I also thank the WSAS project staff and consultants, whose research and writing made this report possible, and the Washington State Department of Commerce for supporting the work. We offer this report to the Legislature, the Utilities and Transportation Commission, utilities, and the public as a foundation for the decisions ahead.

Anjan Bose
Chair, Oversight Committee Regents Professor, Washington State University