Wyoming enacted legislation in February 2001 that established statewide net metering. The law applies to investor-owned utilities, electric cooperatives and irrigation districts. Eligible technologies include solar, wind, biomass and hydropower systems up to 25 kilowatts (kW) in capacity. Systems must be intended primarily to offset part or all of the customer-generator's requirements for electricity.
Net excess generation (NEG) is treated as a kilowatt-hour (kWh) credit or other compensation on the customer's following bill.* At the beginning of the calendar year, a utility will purchase any unused credits at the utility's avoided-cost rate. Utilities may not charge net-metered customers any additional fees beyond the minimum monthly charges that apply to other (non-net-metered) utility customers in the same rate class.
Systems must meet NEC, IEEE and UL technical standards. In addition, system owners must install a manual, lockable external disconnect switch and are responsible for all costs related to any modifications to the systems that may be required by the electric utility for purposes of safety and reliability. The Wyoming Public Service Commission (PSC) is authorized to adopt additional control and testing requirements deemed necessary to protect public safety and system reliability.
* The latter "compensation" option has apparently been interpreted by the PSC to give utilities the freedom to apply rates other than the retail rate to monthly NEG. For instance, the Wyrulec Co. net metering tariff approved by the PSC in April 2008 applies the avoided-cost rate to monthly NEG to arrive at a monetary credit that is applied to the customer's next bill. Other utilities such as Rocky Mountain Power (see tariff) credit monthly NEG as a kWh credit, which equates to the full retail rate.