Minnesota Rate Review

In November 2020 we filed a request to increase rates with the Minnesota Public Utilities Commission (MPUC). The filing starts an approximately 18-month process, often referred to as a rate case, during which the MPUC:

  1. Reviews the costs we incur to provide customers with energy and related services.
  2. Determines the appropriate prices for using those services.

Bill changes

Please view our January bill changes mailer and the below video for information about bill changes beginning with January 2021 energy use. 


We’re creating a cleaner energy future while keeping the prices our customers pay among the lowest in the nation. Making this request now benefits our customers by better preparing us for long-term success in providing safe, reliable, low-cost electricity.

Cleaner energy
The Merricourt Wind Energy Center, a 150-MW wind generation facility in southeast North Dakota, and Astoria Station, a 245-MW simple-cycle natural gas combustion turbine in east central South Dakota, are part of our plan to meet customers’ future energy and capacity needs, replace expiring power purchase agreements, and prepare for the 2021 retirement of our 1950s-era coal-fired Hoot Lake Plant. Astoria Station complements our wind resources by providing a low-emission option when the wind isn’t blowing. Backing wind with natural gas captures the low-cost energy made possible by the current market for wind generation while helping to ensure sufficient reliability from resources we can ramp up quickly during periods of high energy demand.

Smarter technologies 
Our recently implemented Customer Information System allows customers more access and options related to their energy use and our services, enabling them to get more for their energy dollar.

Rising costs
The MPUC established our current rates in 2017 based on 2016 costs.

Filing documents

Volume 1 - Notice of Change in Rates - Interim Rate Petition

  • Index
  • Filing Letter
  • Notice of Change in Rates
  • Notice and Petition for Interim Rates
  • Agreement and Undertaking, and Certification
  • Interim Supporting Schedules and Workpapers
  • Summary of Present and Interim Revenue
  • Interim Tariff Sheets – Redlined
  • Interim Tariff Sheets – Non-Redlined
  • Proposed Notices

Volume 2A - Direct Testimony and Supporting Schedules

  • Index
    • Bruce Gerhardson
      • Overview of Request
      • Background on Otter Tail Power Company
      • Policy Perspectives
    • Tyler A. Akerman
      • Capital Budget Process
      • Rate Base and Adjustments
      • Operating Statement and Adjustments
      • Revenue Requirement
    • Stuart D. Tommerdahl
      • Revenue Requirement Issues
      • Regulatory Issues
    • Christy L. Petersen
      • Operations and Maintenance Budget Process
      • Operations and Maintenance Expenses
      • Employee Expense Reporting
    • Bryce C. Haugen
      • Transition of Capital Projects from Riders to Base Rates
      • Class Cost of Service
      • Class Revenue Apportionment

Volume 2B - Direct Testimony and Supporting Schedules 

  • Index
    • Kevin G. Moug
      • Financial Soundness
      • Capital Structure
      • Cost of Capital
    • Ann Bulkley
      • Return of Equity
    • Peter E. Wasberg
      • Employee Compensation
    • Brian H. Draxten
      • Astoria Station
    • Kirk A. Phinney
      • Astoria Station Project

Volume 2C - Direct Testimony and Supporting Schedules

  • Index
    • Brian J. Boss
      • Revenue Decoupling
    • Jason A. Grenier
      • Conservation Improvement Program
      • Innovation
      • Customer Experience
    • Debra K. Opatz
      • Energy Sales Forecast
    • Daniel G. Hansen
      • Energy Sales Forecast
      • Revenue Decoupling
    • David G. Prazak
      • Rate Design

Volume 2D - Proposed Redlined and Non-Redlined Tariff Sheets 

  • Index
  • Proposed Tariff Sheets – Redlined
  • Proposed Tariff Sheets – Non-Redlined

Volume 3 - Required Information

Required Information

A. Jurisdictional Financial Summary Schedules (Rule 7825.3900)
    Summary of Revenue Requirements – Proposed Test Year 2021
    Jurisdictional Financial Summary Schedule

B. Rate Base Schedules (Rule 7825.4000)
    1. Rate Base Summary
    2. Detailed Rate Base Components
       a. Materials and Supplies
       b. Fuel Stocks
       c. Prepayments
       d. Customer Advances and Deposits
       e. Cash Working Capital
    3. Rate Base Adjustments
    4. Summary of Approaches and Assumptions Used
    5. Rate Base Jurisdictional Allocation Factors

C. Operating Income Schedule
    1. Jurisdictional Statement of Operating Income
    2. Statement of Operating Income - Jurisdictional
    3. Statement of Operating Income – Unadjusted Year 2021 and Proposed Test Year 2021
    4. Computation of Federal and State Income Taxes
    5. Computation of Deferred Income Taxes
    6. Development of Federal and State Income Tax Rates
    7. Operating Income Statement Adjustments Schedule
    8. Summary of Approaches and Assumptions Used
    9. Operating Income Statement Allocation Factors

D. Rate of Return Cost of Capital Schedules (Rule 7825.4200)
    1.a. Summary Schedule, Otter Tail Power Company
    1.b. Summary Schedule, Otter Tail Corporation
    2.a. Composite Cost of Long-Term Debt, Otter Tail Power Company
    2.b. Composite Cost of Long-Term Debt, Otter Tail Corporation
    3.a. Cost of Short-Term Debt, Otter Tail Power Company
    3.b. Cost of Short-Term Debt, Otter Tail Corporation
    4.a. Common-Equity, Otter Tail Power Company
    4.b. Common-Equity, Otter Tail Corporation

E. Rate Structure and Design Information (Rule 7825.4300)
    1. Proposed Test Year 2021 Operating Revenue Summary Comparison - NOT PUBLIC
    2. Proposed Test Year 2021 Operating Revenue Detailed Comparison - NOT PUBLIC
    3. Class Cost of Service Study
    4. Sales Reconciliation between Sales Forecast Groups and CCOSS and Rate Design Classes - NOT PUBLIC

F. Other Supplemental Information
    1. Annual Report and Statistical Supplement
    2. Gross Revenue Conversion Factor

G. Commission Policy Information
    1. Advertising
    2. Charitable Contributions
    3. Organization Dues
    4. Research Expense

H. Travel, Entertainment, and Related Employee Expenses - NOT PUBLIC
(Statute 216B.16, Subp. 17)

Volume 4A - Work Papers


A. Proposed Test Year 2021 Workpapers
    1. Jurisdictional Cost of Service Study (JCOSS)
    2. Class Cost of Service Study (CCOSS)
    3. Functionalization
    4. Input Summary
    5. Proposed Test Year 2021 Adjustments
        TY-01 – Normalized Plant in Service
        TY-02 – Plant Outage Normalization
        TY-03 – Rate Case Expenses
        TY-04 – ESSRP
        TY-05 – Hoot Lake Plant Normalization
        TY-06 – Lignite Energy Dues
        TY-07 – Economic Development Costs
        TY-08 – Remove Rider Revenues
        TY-09 – Electric Vehicle Charging Stations
        TY-10 – Update to Pension and FAS 106 Expense

B. 2021 Regulatory Year Workpapers
    1. Jurisdictional Cost of Service Study (JCOSS)
    2. Functionalization
    3. Input Summary
    4. Work Papers A-D, MN

C. Interim Cost of Service Study
    1. Jurisdictional Interim Cost of Service Study
    2. Proposed Interim Test Year 2021 Adjustments
        ITY-01 – Proration of Federal ADIT
        ITY-02 – CIP Surcharge and Expense removal
        ITY-03 – Big Stone II Transmission
        ITY-04 – Credit Card Fees
        ITY-05 – ECRR Tracker Balance
        ITY-06 – Hoot Lake Plant & Hydro Depreciation Deferral
        ITY-07 – SPP Expense Tracker Balance

D. Bulkley Cost of Capital Workpapers

Volume 4B - Lead Lag Study

  • Index
  • Lead Lag Study

Volume 5 - Budget Documentation

  • Index
  • O&M Budget Process
  • Capital Budget Process