Our Operations

Our Customers

We provide electricity to approximately 132,500 customers in 422 communities across western Minnesota, eastern North Dakota, and northeastern South Dakota.

Total Customers



North Dakota


South Dakota


Total customers


Customers by Category







Large commercial




Other public authorities


New Customer Information System

Our Customer Information System (CIS) performs billing, processes payments, and manages customer account information such as account balances, payment programs, and participation in demand-side management. In February 2016 we began implementation with our vendor, Cayenta, to replace our aging CIS with a new system to better meet the needs of our company and our customers. With the implementation of the new system in February 2019, customer categories were adjusted—seasonal accounts are now included as part of residential and commercial, commercial and large commercial experienced reclassification of customers based on rate, and streetlighting and other public authorities are considered separately. 

Our Supply Chain

For the purposes of this report, we’re defining our supply chain to include major suppliers in five primary areas across our three-state service area.

  1. Wind farm and combustion turbine sites: Software and information technology hardware, consulting and maintenance services, and parts and equipment repair.
  2. Coal-fired power plant sites: Fuel, fuel transportation, fuel reagents (pebble lime, powdered carbon, and anhydrous ammonia), operations monitoring and maintenance services, engineering services, and plant upgrades.
  3. Purchased power: Capacity and energy from counterparties and the Midcontinent Independent System Operator, Inc., (MISO) energy market.
  4. Transmission and distribution materials: Poles, conductor wire, fiber-optic communications wire, connecting and insulating hardware, transformers, meters, and substation and switchyard construction services and equipment.
  5. Companywide services: Software and information technology hardware, consulting services, contract labor (including project-based construction workers), recycling and disposal services, and communications and miscellaneous equipment.

Supplier Engagement

Otter Tail Power Company purchasing agreements require suppliers to abide by the Otter Tail Corporation Code of Conduct and federal Equal Employment Opportunity requirements; conform to applicable governmental permits, licenses, and applicable laws; meet or exceed all OSHA requirements; and meet or exceed all reporting requirements for the accidental release of hazardous materials. For large projects we screen construction contractors based on their last five years of safety performance. We require software and information technology hardware suppliers to adhere to cybersecurity requirements. All suppliers must provide proof of insurance for workers compensation, employer’s liability, auto insurance, pollution liability, and general liability.

Energy Resources and Fuel Suppliers

We examine new energy resources and fuel suppliers to ensure they have a history of compliance with all regulatory and legal environmental requirements and have a record of responsible business practices. In 2018 we engaged in a notable supplier agreement with Mitsubishi Hitachi Power Systems Americas, Inc., to purchase a combustion turbine generator for Astoria Station. We ensured that the turbine will be able to meet or exceed all environmental requirements. This turbine is set to be installed in 2020 and will be placed into operation in early 2021.

Our Electrical Use

Our business processes, including generating and moving energy, require energy. Below is our 2019 electrical use. We use a portion of the energy we generate, therefore, our resource mix and renewable resource usage mirrors that of our customers. 

2019 Electrical Use



Dollar Amount




North Dakota



South Dakota