Ohio PUCO Level 2 Commercial Solar Interconnection Guide

Key Takeaways

• Ohio's Public Utilities Commission of Ohio (PUCO) Rule 4901:1-22-07 governs Level 2 interconnection for commercial solar and storage systems.
• Export capacity limits range from 500 kW to 3 MW, depending on the line voltage.
• The initial review period for a complete application is thirty calendar days.
• Application fees are up to $100 plus $1 per kilowatt of export capacity.

What is Ohio PUCO Level 2 Interconnection for Commercial Solar?

Ohio's Public Utilities Commission of Ohio (PUCO) Rule 4901:1-22-07 establishes the framework for Level 2 expedited interconnection review. This process applies to commercial solar and storage systems up to 3 MW. It outlines specific technical requirements and review procedures for connecting distributed generation to the electric grid.

This guide details the key provisions of OAC Rule 4901:1-22-07. It covers capacity limits, screening criteria, review timelines, and associated fees (August 2026).

How We Verified This Information

We accessed the official text of the Ohio Administrative Code Rule 4901:1-22-07 directly from the Ohio government's codes website on August 23, 2026. All figures and statutory language presented here are drawn verbatim from this primary source.

What are the Capacity Limits for Level 2 Interconnection?

The maximum export capacity for a Level 2 interconnection depends on the voltage of the utility line to which the system connects. These limits are defined in the Ohio Administrative Code Rule 4901:1-22-07.

| 15 kV to less than or equal to 69 kV | Less than or equal to 3 MW | Figures as of August 2026.

For example, a commercial solar project connecting to a utility line operating at 13 kV would be limited to an export capacity of 2 MW. A project on a 4.16 kV line would be limited to 500 kW.

What Technical Screening Criteria Apply to Level 2 Systems?

Level 2 interconnection applications undergo specific technical screenings to ensure grid stability and safety. These criteria are detailed in OAC Rule 4901:1-22-07.

Radial Distribution Circuit Limits

For systems connecting to a radial distribution circuit, the total aggregated generation, including the proposed Distributed Energy Resource (DER), must not exceed one hundred per cent of the line section's relevant minimum load. This minimum load is measured at the substation or calculated for the line section.

Fault Current Contribution

The proposed DER, when aggregated with other DER generation on the distribution circuit, must not contribute more than ten per cent to the distribution circuit's maximum fault current. This applies at the point on the primary voltage distribution line nearest the point of common coupling.

Equipment Fault Current Capability

The aggregated DER generation must not cause any distribution protective devices or equipment to be exposed to fault currents exceeding ninety per cent of their short circuit interrupting capability. This includes substation breakers, fuse cutouts, and line reclosers.

Shared Secondary Transformer Limit

If the proposed DER is to be interconnected on a single-phase shared secondary line, the aggregate DER generation capacity on that line, including the proposed DER, must not exceed sixty-five per cent of the transformer nameplate rating.

Spot Network Limits

For interconnections to a spot or area network, the proposed DER's capacity must not exceed the lesser of five per cent of the network's maximum load or fifty kilowatts.

These screenings help prevent grid instability and equipment damage from over-generation or excessive fault currents.

What is the Review Process and Timeline for Level 2 Interconnection?

The Level 2 interconnection process in Ohio follows a defined timeline once a complete application is submitted.

Initial Review Period

After the Electric Distribution Utility (EDU) notifies the applicant that it has received a complete application, the EDU must perform an initial review. This review uses the criteria set forth in paragraph (B) of OAC Rule 4901:1-22-07. The EDU must notify the applicant of the results within thirty calendar days of acknowledging the complete application.

Interconnection Agreement Delivery

If the application is approved following the initial review, the EDU will provide the applicant with a standard interconnection agreement. This agreement must be delivered within ten calendar days after the determination of approval.

Costs for System Modifications

If the interconnection requires the construction of new facilities or modifications to existing facilities on the EDU's system, the applicant is responsible for covering all estimated costs associated with these modifications.

Understanding these timelines helps project developers plan their commercial solar installations effectively.

What are the Fees for Level 2 Interconnection Applications?

The Public Utilities Commission of Ohio (PUCO) allows EDUs to charge specific fees for processing Level 2 interconnection applications. These fees are outlined in the EDU's tariff.

The Level 2 review processing fees include:

• An application fee of up to one hundred dollars.
• An additional charge of one dollar per kilowatt of the DER's export capacity rating.

For example, a 500 kW commercial solar system would incur an application fee of up to $100 plus $500 (500 kW * $1/kW), totaling up to $600 (August 2026).

How Does Level 2 Compare to Other Interconnection Levels in Ohio?

Ohio's interconnection rules categorize systems into different levels based on their size and complexity. Level 2 is designed for expedited review of commercial-scale systems.

For smaller residential or small commercial systems, you may need to consult our guide on Ohio PUCO Level 1 25kW Solar Interconnection Procedure. For larger or more complex projects that exceed Level 2 limits or fail its screening criteria, the Ohio PUCO Level 3 Study Process and Interconnection Guide provides relevant information.

You can also review the comprehensive Ohio PUCO Rule 4901:1-22 Distributed Generation Interconnection Guide for a broader overview of all interconnection rules. To estimate the potential size of your solar installation, you can use a solar sizing tool.