On July 11, 2022, the Arizona Corporation Commission (ACC) unanimously approved Tucson Electric Power’s (TEP’s) Interconnection Manual. The final manual was written with direct input from the Arizona Solar Energy Industries Association (ARISEIA) and other stakeholders in renewable energy industry to simplify solar installations using the latest technology. The new interconnection manual lays the foundation for increasing amounts of solar and batteries powering and greening TEP’s grid. ARISEIA drafted and submitted multiple letters to the ACC outlining changes and suggesting revision language, much of which was adopted in the final interconnection manual.
The previous manual was written decades ago before solar systems were common, and the technology was new and unproven. Today, solar on homes, businesses, and organizations’ properties produce clean power delivered directly to end users, and their neighbors when solar power flows back to the grid. New solar and battery systems can save customers money, green their energy use and their neighborhood’s grid, and help transition Tucson to a leading green city.
The new interconnection manual makes the process simpler and easier to build and operate solar systems, and the latest technology is included to increase the amount of solar that can be installed on TEP’s grid. Some of the new highlights are:
- Meter Socket Adapters (MSA’s): these devices connect to the meter socket and allow a solar and/or battery system to directly tie into the electrical service in minutes, without needing extensive upgrades.
- Maximum Capacity System Sizing: TEP updated their rules to recognize that solar and/or battery systems can have their output to the grid limited, either partially or be fully non-exporting. These systems will have simpler interconnection rules when based on their “Operating Characteristics,” not just their nameplate capacity.
- Larger system sizes: The ACC required systems as large as 2MW by fast tracked by all the Arizona regulated utilities. TEP has adopted the increased size limit and simplified interconnection rules these large systems. New Jersey is still the national leader with fast track interconnection sizing at 3MW, which AZ has moved ahead of CA, which has a 1MW size limit for fast tracked solar interconnections.
- Smart Inverters: Including smart inverters with standardized grid support settings can dramatically increase the amount of solar on any individual circuit, up to 3x or more. 
- Installation Timelines: TEP amended their installation timelines past 180 days as long as demonstrable progress has been made on a project, an important improvement for projects with long permitting, financing, or installation timelines.
Solar Gain is a proud member of ARISEIA and contributed to the Interconnection Manual draft revisions and stakeholder meetings. Please call Solar Gain with questions about how the new Interconnection Manual can help your home or organization project go solar.
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 Smart Inverter circuit hosting capacity, available here.