Iowa Utilities Commission 199 IAC 45.9: Level 2 Solar Interconnection Guide

Key Takeaways

• Level 2 expedited review applies to lab-certified distributed generation facilities (August 2026).
• Each generating unit must have a nameplate capacity rating of 2 MVA or less (August 2026).
• Utilities have 10 business days to review completeness and 20 business days for technical evaluation (August 2026).
• The facility must not exceed 15 percent of the total annual peak load (August 2026).

Understanding Iowa's 199 IAC 45.9 Level 2 Solar Interconnection Rules

The Iowa Utilities Commission (IUC) sets the rules for connecting solar energy systems to the grid. Iowa Administrative Code Chapter 199-45.9 outlines the requirements for Level 2 expedited review. This process applies to specific types of distributed generation facilities.

Level 2 review is for systems that are lab-certified. The distributed generation facility must be lab-certified (August 2026). Additionally, the customer-generator facility must have a nameplate capacity rating for each generating unit of 2 MVA or less (August 2026).

Technical Screening Criteria for Level 2 Interconnection

The IUC's 199 IAC 45.9 rules include several technical screens to ensure grid stability and safety. These criteria determine if a solar project qualifies for Level 2 expedited review.

The facility will not exceed 15 percent of the total annual peak load as most recently measured at the substation or calculated for the line section (August 2026). It will also not contribute more than 10 percent to the distribution circuit's maximum fault current at the point on the primary line (August 2026).

Furthermore, the facility shall not cause any electric utility distribution devices to be exposed to fault currents exceeding 90 percent of the electric utility distribution devices' short-circuit interrupting capability (August 2026).

For systems on a shared secondary line, the aggregate generation capacity, including the proposed distributed generation facility, will not exceed 20 kVA (August 2026). The addition of the facility must also not create an imbalance between the two sides of the 240-volt service of more than 20 percent of the nameplate rating of the service transformer (August 2026).

A transient stability screen also applies: the facility will not exceed 10 MVA in an area where there are transient stability limitations to generating units (August 2026).

Administrative Timelines for Level 2 Interconnection Requests

The interconnection process involves specific administrative timelines for both the utility and the applicant. These timelines ensure a structured and predictable review process.

Within ten business days after receiving the interconnection request, the utility shall inform the applicant as to whether the interconnection request is complete (August 2026).

Following a complete request, the utility has 20 business days to evaluate the interconnection request using the Level 2 screening criteria (August 2026).

If the project qualifies, the utility shall provide the applicant with the Levels 2 to 4 Distributed Generation Interconnection Agreement within three business days of the date the utility makes its determination (August 2026).

The applicant then has 30 business days to sign and return the agreement to the utility (August 2026). An initial request for a 15-business-day extension in writing before the end of the 30-day period will not be denied by the utility (August 2026).

Related Regulatory Guides

For smaller residential systems up to 20 kVA in Iowa, see our Iowa Utilities Commission 199 IAC 45.8 Level 1 Interconnection Guide. You can also compare neighboring Midwest commercial interconnection rules in our Illinois ICC Part 466 Level 2 Interconnection Guide and Minnesota PUC Interconnection Rules Guide. Before engineering your project, calculate circuit penetration thresholds with our solar sizing tool.