Minnesota Interconnection

2025 Distributed Solar Energy Standard (DSES) Request for Proposals 

In early 2025 we'll submit a Request for Proposals (RFP) seeking third-party developers to install more distributed solar generation onto our system. The spreadsheet linked below contains pertinent minimum daytime loading (MDL) data information. 

Minimum daytime loading data

How to interconnect with our system

If you generate electricity and are looking to interconnect with our system, the information below outlines the process, requirements, and more.

Overview

There are four basic phases of the interconnection process. This quick-start guide provides an overview.

Process

Distributed Energy Resource Interconnection Process (MN DIP)

• Section 1 – Application
  • Integration Flowchart
• Section 2 – Simplified Process
  • General Simplified Process Flowchart
• Section 3 – Fast Track Process
  • General Fast Track Process Flowchart
• Section 4 – Study Process
  • General Study Process Flowchart
• Section 5 – Provisions that apply to all applications

• Attachment 1: Pre-application Report Form Request
• Attachment 2: Simplified Application Form
  • Terms and Conditions for Interconnecting an Inverter-based DER no Larger than 20 kW
  • For Energy Storage
  • Certificate of Completion
• Attachment 3: Interconnection Application Form
  • Pay application fee online
• Attachment 4: Certification Codes and Standards
• Attachment 5: Certification of Distributed Energy Resource Equipment
• Attachment 6: System Impact Study Agreement
• Attachment 7: Facility Study Agreement

Glossary of Terms

Surcharge

The state of Minnesota now requires utilities to assess and collect a surcharge of $50 on each interconnection application, which we remit to the Minnesota Public Utilities Commission. This surcharge is on top of the other application charges.

You may pay your application fee online or send a paper copy of your application along with the application fee to:

Otter Tail Power Company
Attn: Interconnection Coordinator
215 S. Cascade St.
Fergus Falls, MN 56538-0496

Interconnection agreement

• Minnesota Distributed Energy Resource Interconnection Agreement (MN DIA)
• Uniform Statewide Contract required by Minnesota Administrative Rules 7835.9910 for use between a utility and cogeneration or small power production facilities having less than 1 MW of capacity
• Purchase-power riders and applicability matrix
  • Small power producer rider (Net energy billing rate) - residential, farm, general service, large general service
  • Small power producer rider (Simultaneous purchase and sale billing rate) - firm power, nonfirm power
  • Small power producer rider (Time-of-day purchase rates) - firm power, nonfirm power
  • Distributed generation service rider
  • Standby service tariff

Technical requirements

In addition to the procedures listed above, Minnesota Distributed Energy Resource interconnecting customers are required to abide by the following technical requirements to our electrical system:

• State of Minnesota Technical Interconnection and Interoperability Requirements (TIIR)
• Otter Tail Power's Technical Standards Manual (TSM) (Version 2023)

As of January 1, 2024, we require the use of UL 1741SB (3^rd Ed.) certified inverter(s) and Utility Required Profiles (URPs) to ensure the inverter-type DER system(s) adhere to our newly updated Technical Specifications Manual (TSM) requirements, shown above. 

For additional information on Utility Required Profiles, please visit the EPRI website and review a copy of EPRI’s Technical Report titled, ‘Common File Format for DER Settings Exchange and Storage’.

• Utility Required Profile (URP) Logistics Q&A - Intentions of Use

Otter Tail Power’s Utility Required Profiles (URP’s):

• Example Version of URP (-SS): Required by Otter Tail Power’s new inverter settings requirements as outlined above in the TSM.
• URP (-AS) - “Applied Settings” file: Required to be returned to Otter Tail Power from the DER Installer following the witness testing and successful site inspection.
  • Example Version of URP (-AS) - (Not intended for use)

Questions?

• Contact our Generation Interconnection Coordinator regarding the interconnection process and agreements.
• Contact our Principal Resource Planner regarding pricing and purchase agreements.