Solar Photovoltaics

Renewables Portfolio Standard

California’s Renewables Portfolio Standard (RPS) was originally established by legislation enacted in 2002. Subsequent amendments to the law have resulted in a requirement for California’s electric utilities to have 60% of their retail sales derived from eligible renewable energy resources in 2030 and all subsequent years. The law established interim targets for the utilities as shown below. Publicly Owned Municipal Utilities (POUs) are not regulated by the CPUC but are affected by the law nonetheless, and their governing boards are charged with establishing procurement requirements based on the interim goals below:

  • 20% of retail sales by December 31, 2013
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Interconnection Standards

New Hampshire requires all utilities selling electricity in the state to offer net metering to customers who own or operate systems up to one megawatt (MW) in capacity that generate electricity using solar, wind, geothermal, hydro, tidal, wave, biomass, landfill gas, bio-oil, or biodiesel; the capacity for group net-metered systems with a municipal host only is 5 MW. Combined heat and power (CHP) systems that use natural gas, wood pellets, hydrogen, propane, or heating oil are also eligible.*

The PUC's rules for net metering, which distinguish between small customer-generators (up to 100 kilowatts) and large customer-generators (greater than 100 kW

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Interconnection Guidelines

Wyoming's net-metering law includes basic interconnection requirements for systems up to 25 kilowatts (kW) in capacity that generate electricity using solar, wind, hydropower or biomass resources. However, the Wyoming Public Service Commission (PSC) has not established separate interconnection rules. There is no limit on overall enrollment specified by the law. Systems must comply with the National Electrical Code (NEC), Institute of Electrical and Electronic Engineers (IEEE), and Underwriters Laboratories (UL) safety and equipment standards. Customers must install an external disconnect switch at their own expense. The PSC may require additional controls and testing.

Additional liability insurance is not addressed by

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NorthWestern Energy - USB Renewable Energy Fund

NorthWestern Energy (NWE), formerly Montana Power Company, periodically provides funding to its customers for renewable energy projects. In 1997, Montana established the Universal System Benefits (USB) program. The USB legislation requires all electric and gas utilities to establish USB funds for low-income energy assistance, weatherization, energy efficiency activities, and development of renewable energy resources. A typical NorthWestern Energy residential customer pays approximately $1 per month in electric USB charges. In 2021, NorthWestern’s USB charge generated over $10 million, of which about $900,000 was used for renewable resources, and research and development projects.

The E+ Renewable Energy Program provides custom

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Interconnection Standards

The Washington Utilities and Transportation Commission (UTC) adopted interconnection standards for distributed generation (DG) systems up to 20 megawatts (MW) in capacity in 2007, and revised these standards in July 2013. The rules apply to the state's investor-owned utilities (Avista, PacifiCorp, and Puget Sound Energy), but not municipal utilities, public utility districts, or cooperative electric utilities. 

The revised standards provide for three separate levels of interconnection based on system capacity and other requirements. The first level, Tier 1 systems, applies generally to systems up to 25 kilowatts (kW) using inverter-based interconnection equipment. The second tier applies generally to systems sized

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Interconnection Standards

Virginia has two interconnection standards: one for net-metered systems and one for systems that are not net-metered.

Interconnection for Net-Metered Systems

Customer-generators that net meter must comply with the interconnection rules within the regulations governing net metering (20 VAC 5-315-40). These rules apply to residential customers with generation facilities up to 20 kW in capacity and non-residential systems up to 1,000 kW in capacity. Utilities that have already enrolled 1% of their peak load for the previous year are not required to allow additional customers to net meter. More information is available under DSIRE Virginia net metering post. 

Customer-generators with

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Interconnection Standards

Note: Public Utilities Commission Rule 5.500 was effectively amended on March 1, 2024, via Docket No. 19-0856-Rule.

Interconnection rules for all net-metering systems are applied by Rule 5.500. Vermont requires electric utilities to offer net metering to all customers with solar photovoltaic (PV) systems, wind energy systems, fuel cells, or biomass energy systems, among others. The maximum system capacity for net-metered systems is 500 kW. CHP systems that use a non-renewable fuel are limited to 20 kW and must meet an efficiency standard. For schools and school district customers, the capacity limit is 1 MW (also applies to aggregate

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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

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Interconnection Standards

Note: Texas has an ongoing docket, Docket No. 54233, that is considering reforms to interconnection processes.

The Texas Public Utility Regulatory Act (PURA) of 1999 included a provision that "a customer is entitled to have access… to on-site distributed generation," leading the Public Utility Commission of Texas (PUCT) to subsequently adopt interconnection standards. 

System Capacity Requirements

Interconnection rules apply to electrical generating facilities (consisting of one or more on-site distributed-generation units) located at a customer's point of delivery, with a maximum capacity of 10 megawatts (MW) of capacity interconnected at any point in time at the point of common

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Interconnection Standards

Note: In March 2024, Oregon adopted new interconnection rules that address, among other changes, incorporation of energy storage with small generators. The rules move to use export capacity rather than nameplate capacity to evaluate system effects. Starting on June 1, 2024, all interconnecting systems will be required to use smart inverters in compliance with IEEE 1547-2018.

Oregon has three separate interconnection standards: one for net-metered systems; one for small generator facilities (non-net metered systems); and one for large generator facilities (non-net metered systems). Oregon has also established separate net metering requirements and interconnection standards for the state's primary investor-owned utilities

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