Interconnection Standards

Utah requires the state’s only investor-owned utility, Rocky Mountain Power (RMP), and most electric cooperatives* to offer net metering to customers who generate electricity using solar energy, wind energy, hydropower, hydrogen, biomass, landfill gas, geothermal energy, waste gas, or waste heat capture and recovery. The bill that established net metering also established some basic rules for interconnection. In April 2010, the Utah Public Service Commission (PSC) adopted final rules for interconnection. The rules described below took effect April 30, 2010.

Utah’s interconnection rules are based on the Federal Energy Regulatory Commission’s (FERC) interconnection standards for small generators, adopted in May 2005 by FERC Order 2006. Utah’s rules for interconnection include provisions for three levels of interconnection for systems up to 20 megawatts (MW) in capacity, based on system complexity. Interconnection requirements, standards and review procedures are divided into three levels:

• Level 1 Interconnection applies to inverter-based systems with a maximum capacity of 25 kilowatts (kW). These systems must comply with the IEEE 1547 and UL 1741 standards, and other applicable standards. An external disconnect switch is not required for inverter-based systems 10 kW or less.
• Level 2 Interconnection applies to systems with a maximum capacity between 25 kW and 2 MW, or that fail to qualify for Level 1 interconnection. These systems also must comply with the IEEE 1547 and UL 1741 standards, and must be connected to the distribution grid. An external disconnect switch may be required. There are specific limitations on a single system’s potential impact and the aggregate potential impact on the grid under Level 2 interconnection, and the review process is more involved than the review process for Level 1 interconnection.
• Level 3 Interconnection applies to systems 20 MW or less that do not qualify for either Level 1 or Level 2 interconnection. Level 3 interconnection may require studies involving project scope, feasibility, and grid impact. Any study fees will be invoiced to the interconnection customer, but are not to exceed 125% of the utility’s non-binding “good faith estimate” of the cost of the study.

* Beginning in March 2008, electric cooperatives serving fewer than 1,000 customers in Utah may discontinue making net metering available to customers that are not already net metering. In addition, electric cooperatives not headquartered in Utah that serve fewer than 5,000 customers in Utah are authorized to offer net metering to their Utah customers in accordance with a tariff, schedule, or other requirement of the appropriate authority in the state in which the co-op’s headquarters are located.