Ohio PUCO Level 3 Study Process and Interconnection Guide: Understanding the 365-Day Review

Key Takeaways

• Ohio's Level 3 interconnection review process has a maximum timeframe of 365 calendar days.
• Application fees are up to one hundred dollars, plus one dollar per kilowatt of export capacity.
• Engineering studies for Level 3 interconnections are billed at actual cost.
• The Electric Distribution Utility (EDU) must provide an interconnection agreement within ten calendar days of receiving payment for study costs.

What is the Ohio PUCO Level 3 Interconnection Process?

The Public Utilities Commission of Ohio (PUCO) establishes rules for connecting Distributed Energy Resources (DERs) to the grid. Ohio Administrative Code (OAC) Rule 4901:1-22-08 outlines the Level 3 review procedure. This process applies to complex, large-scale, or uncertified DERs that do not qualify for Level 1 or Level 2 interconnection.

The Level 3 review involves detailed engineering studies, including feasibility, system impact, and facilities studies. The Electric Distribution Utility (EDU) performs a review and notifies the applicant of the results within a maximum of 365 calendar days (one year) after receiving a complete application (August 2026). Applicants are responsible for application fees and the actual costs of these engineering studies.

How long does an Ohio Level 3 review take?

The Level 3 review process in Ohio has a statutory maximum timeframe. The Electric Distribution Utility (EDU) must complete its review and notify the applicant of the results within a maximum of three hundred and sixty-five calendar days (one year) (August 2026). This timeframe begins after the EDU confirms it has received a complete application. It includes any required scoping meetings and all studies defined in OAC Rule 4901:1-22-09.

What are the costs associated with an Ohio PUCO Level 3 application?

Applicants for a Level 3 interconnection in Ohio face several potential costs. These include an application fee and charges for engineering studies and system modifications.

The application fee is set at up to one hundred dollars, plus one dollar per kilowatt of the system's export capacity (August 2026).

Beyond the application fee, applicants are responsible for the cost of engineering work. This includes feasibility, system impact, or facilities studies, which are billed at actual cost (August 2026). The EDU must invoice the applicant for these actual study costs within fourteen calendar days after the Level 3 review is complete and approval for interconnection is granted (August 2026).

Applicants are also mandated to cover the actual cost of any modifications to the EDU's system that would not be necessary without the interconnection request (August 2026).

Once the EDU collects payment for the actual costs of the studies, it must provide the applicant with a standard interconnection agreement within ten calendar days (August 2026).

When is a Level 3 review required in Ohio?

A Level 3 review is triggered under specific conditions, primarily when a Distributed Energy Resource (DER) project does not meet the criteria for simpler interconnection processes.

A Level 3 review is required if the DER project either:

• Does not qualify or failed to meet the Level 1 or Level 2 interconnection review requirements (August 2026).
• Does not utilize equipment certified in compliance with the IEEE and UL standards as set forth in OAC Rule 4901:1-22-03 (August 2026).

These conditions ensure that more complex or non-standard installations undergo a thorough engineering assessment to maintain grid safety and reliability.

How does the Electric Distribution Utility (EDU) approve Level 3 interconnections?

The Electric Distribution Utility (EDU) approves a Level 3 interconnection application based on specific criteria related to grid integrity. The EDU must approve an application if it determines that the safety and reliability of the public utility's transmission or distribution system will not be compromised by interconnecting with the generation facility (August 2026). This standard ensures that new DERs do not negatively impact the existing electrical infrastructure or public safety.

How We Verified This Information

We verified the information in this guide by reviewing the Ohio Administrative Code (OAC) Rule 4901:1-22-08, titled "Level 3 review procedure." This rule is the primary source for the Level 3 interconnection process in Ohio. All figures and procedural details are drawn directly from this statutory document. We accessed this source on August 23, 2026.

Navigating Ohio's Interconnection Rules

Understanding the specific requirements for connecting Distributed Energy Resources (DERs) to the grid in Ohio is crucial for project success. The Level 3 process is designed for more complex scenarios, but simpler pathways exist for smaller or certified systems.

For an overview of the broader regulatory framework, consult our Ohio PUCO Rule 4901:1-22 Distributed Generation Interconnection Guide. If your project might qualify for a less intensive review, explore our guides on Ohio PUCO Level 1 (25kW) Solar Interconnection Procedure and Ohio PUCO Level 2 Commercial Solar Interconnection Guide.

Proper sizing of your solar system is also a critical first step. You can use our solar sizing tool to estimate your needs before engaging with the interconnection process.