The combination of interconnection and net metering is essential to cost-effectively realize the benefits of distributed solar energy.
Interconnection and Net Metering Best Practices
As residents and businesses increasingly choose to install solar, utilities are searching for new processes to efficiently meet increased customer requests for interconnection to the grid. Responding to this challenge, Northwest Solar Communities convened a team to develop interconnection practices that make the process of going solar simple, fast, and cost effective for customers and the utilities that serve them.
The following best practices are recommended for inverter-based PV systems with a nameplate capacity of 25 kW or less. Some practices are already in place in Oregon or Washington.
- For utilities that are not already required to do so under state law, consider offering annualized net metering with monthly carry forward that is reset in March.
- Provide customers easy access to their historic annual and monthly electricity consumption data.
- Net metered billing statements should clearly show the net energy consumed from the utility, and any energy or dollar credits carried forward as a result of solar generation in previous billing periods.
- Allow meter aggregation on contiguous sites with single owner.
- For systems installed under a production based incentive, combine the application for interconnection with the application for a production meter and/or net metering.
- Provide an expedited process for systems under 25 kW with a maximum review time of three business days.
- Keep the application simple. For a standard inverter-based rooftop solar system, the interconnection application should be no more than two pages plus terms and conditions.
- Make the application form easy to find online.
- Allow applications to be submitted electronically by email or through an online platform.
- Consider combining the application process with incentive and / or permit applications.
- Provide a single point of contact for every aspect of interconnection and metering at the utility.
- Make it easy for a customer to check the status of their application.
- Eliminate submission of single line drawings with the following possible exceptions:
- Systems that incorporate a battery backup
- Systems installed under a production incentive with a designated production meter
- Systems installed on a three phase service using single phase inverters
Interconnection & Inspection
- Do not require any hardware that is not specifically required by locally adopted standards and codes including:
- Visible, lockable AC disconnects except as need to ensure the safety of utility personnel
- Rooftop disconnects
- Consider eliminating utility site inspections by accepting code and safety inspection results from the local jurisdiction.
- If a utility inspection is required, consider the following policies:
- Provide a specific time of inspection to the system installer.
- Make information on inspection requirements easy to access.
- Eliminate redundant site visits by combining inspections.
The following forms can adopted by utilities to expedite the process.
- Sample EZ Application for Interconnection, Net Metering and Production Metering
- Template One Line Diagram Requirements
- Template One-Line Diagram and Site Plan for 4 String (fillable format)
- Template One-Line Diagram and Site Plan for 6 String
Additional Interconnection and Net Metering Resources
Distributed Generation Interconnection Workshops
Northwest Solar Communities held a series of in person trainings in Oregon in 2014 and 2015. Materials and copies of the presentations are available on the Northwest Solar Communities website.
Webinar | Meeting the Solar Interconnection Rush
Northwest SEED, Seattle City Light, Snohomish PUD, and Puget Sound Energy discuss opportunities and efforts to improve the customer service side of interconnection. Delivered March 26, 2015
Report | IREC Model Interconnection Procedures
IREC has participated in dozens of state utility commission rule makings and has identified emerging best practices in these updated model procedures. Published April 2013.
Report | Washington UTC Interconnection Generators Rulemaking UE112-133
The Washington UTC is completing a multi-year process to revise rules for interconnection of electric generators under WAC 480-108. The proposed rules are expected to be adopted in the summer of 2013.
Website | Freeing the Grid
Now it its sixth year, this policy guide from Network for New Energy Choices grades all 50 states on net metering and interconnection best practices. Updated 2013.
Webinar | Streamlined Interconnection for Solar PV
ESSP partners WA Department of Commerce, Northwest SEED, Seattle City Light, Snohomish PUD, and Puget Sound Energy explain current interconnection practices and opportunities for process improvements. Delivered December 4, 2012.
Report | Streamlined Interconnection for Solar PV
Developed by the Evergreen State Solar Project, this report provides a detailed look at the interconnection process and potential improvements thereto. Published October 18, 2012.
Report | Federal Energy Regulatory Commission Small Generator Interconnection Procedures and Screens
The FERC SGIP contains the technical procedures that a small generator and utility must follow when connecting the generator to utility lines subject to FERC jurisdiction (that is, when the project is not net metered.) The standards are embodied in a single set of ten screens for the 10kW Inverter Process and the Fast Track Process. Published July 2010.