WA SB5727

Creates a battery incentive program requiring utilities with over 100,000 customers to offer one-time payments for residential battery storage systems: up to $765/kWh for low/moderate-income customers and up to $450/kWh for others, capped at 18 kWh per customer

Requires participating utilities to implement either time-of-use rates by July 1, 2026, or incorporate customer batteries into a utility-operated virtual power plant for grid management

At least 40% of program benefits must go to low-income households, moderate-income households (80-115% of median family income), low-income service providers, housing authorities, or tribal governments

Provides tax credits to qualified light and power businesses equal to incentive payments made plus up to 20% for program expenses like advanced metering infrastructure and virtual power plant subscription fees

Program runs from July 1, 2026 through June 30, 2036, with tax credits claimable until June 30, 2038, and performance review scheduled for 2030 with a goal of 50 megawatt-hours of installed battery storage