Washington's net-metering law applies to systems up to 100 kilowatts (kW) in capacity that generate electricity using solar, wind, hydro, biogas from animal waste, or combined heat and power technologies (including fuel cells). All customer classes are eligible, and all utilities -- including municipal utilities and electric cooperatives -- must offer net metering.
Net metering is available on a first-come, first-served basis until the cumulative generating capacity of net-metered systems equals 0.25% of a utility’s peak demand during 1996. This limit will increase to 0.5% on January 1, 2014. At least one-half of the utility’s available aggregate net metering capacity is reserved for systems generating electricity using renewables.
Although the utility must provide a single, bi-directional meter, the customer must provide the current transformer enclosure (if required), the meter socket or sockets, and junction box. Net excess generation (NEG) is credited to the customer’s next bill at the utility’s retail rate. However, on April 30 of each calendar year, any remaining NEG is surrendered to the utility without compensation to the customer. Meter aggregation, the combination of readings from and billings for all meters on property owned or leased by a customer within a single utility's service territory, is provided at a customer's request. (Meter aggregation is limited to 100 kW per customer.) The electricity produced by a meter-aggregated customer is first used to offset electricity provided by the utility to that customer; any excess kilowatt-hours from a billing period will be credited equally to the customer's remaining meters.
Net-metered systems must include all equipment necessary to meet applicable safety, power quality and interconnection requirements established by the National Electric Code, the National Electric Safety Code, the Institute of Electrical and Electronic Engineers (IEEE) and Underwriters Laboratories (UL). Utilities may not require net-metered customers to comply with additional safety or performance standards, or to purchase additional liability insurance. Utilities also may not charge customers any additional standby, capacity, interconnection, or other fee or charge without approval from the Washington Utilities and Transportation Commission (UTC). Utilities are not liable for damage caused by net-metered systems.
Taking advantage of Washington's [http://dsireusa.org/incentives/incentive.cfm?Incentive_Code=WA27F&re=1&ee=1 Renewable Energy Production Incentives] does not reduce or impact savings achieved through net metering. However, utilities may require separate metering for production, and customers must pay all costs associated with the installation of production metering. While the ownership of renewable energy credits (RECs) associated with generation is not specified in the state's net-metering law, the production incentive law states that customer-generators retain ownership of RECs.