Resource planning | Tri-State Generation and Transmission Association, Inc

Resource planning

Electric resource planning (ERP) for resources involves developing and assessing alternative scenarios based on a range of growth rates, resource costs, capital costs, types of generation resources, energy efficiency programs, levels of emissions, water usage and other considerations. Various resource plan scenarios are compared on the basis of cost, reliability, environmental characteristics and other factors.

Operating under the cooperative principles, Tri-State seeks to keep members and the public informed. Your participation in this process is encouraged.

2023 ERP / IRP Planning

To view the 2023 ERP filings, go to the Colorado Public Utilities Commission (PUC) Electronic Filings web page. Search for Documents under Proceeding Number 23A-0585E. The RPP covered by the 2023 ERP was 2024 to 2043.

Phase I of Tri-State’s 2023 ERP concluded on September 12, 2024 with final approval of an unopposed comprehensive settlement agreement. Phase II of Tri-State’s 2023 ERP was initiated on September 13, 2024 with the release of three Requests for Proposals for generation and storage resources with commercial operations dates between 2026 and 2031.

2020 ERP Filing

To view the 2020 ERP filings, go to the Colorado Public Utilities Commission (PUC) Electronic Filings web page. Search for Documents under Proceeding Number 20A-0528E. The RPP covered by the 2020 ERP was 2021 to 2040.

Tri-State’s Phase I 2020 ERP concluded on April 18, 2022 through an uncontested comprehensive settlement agreement. Tri-State’s Phase II 2020 ERP was initiated on May 18, 2022 with the release of a Request for Proposals for clean generation resources with commercial operations dates in 2025 or 2026.

On January 11, 2024, the Colorado Public Utilities Commission approved Tri-State’s Proposal to Release Bid Information from the 2020 ERP Phase II. C24-0025 Commission Decision Approving Tri-State's Proposal To Release Confidential And Highly Confidential Information.

Proposals were accepted through September 16, 2022. A list of the 2020 ERP Phase II Competitive Solicitation Bid Information can be found here.

2020 IRP Public Process

Click here to view the IRP document that was filed with WAPA in 2020.

Tri-State's Resource Planning Process:

Tri-State runs a base case along with various scenarios which represent the anticipated financial, environmental, and reliability impacts of potential variations in forecasting assumptions. The purpose of the base case and scenarios is to identify Tri-State's resource needs within the RPP and the most reliable, cost-effective way to fill that need.

The scenario process begins with an expansion plan modeling that is used to identify the most reliable, cost-effective plan for a given scenario. From there, the expansion plan is dispatched in an hourly production cost model, and the results along with other financial data related to resources, including but not limited to transmission and generation build capital expenses, are sent to financial models to determine the final Present Value Revenue Requirement of each scenario.

Tri-State considers both supply and demand side resources in regards to expansion planning. Both build and purchases options are considered. Generic resources are modeled as available throughout Tri-State's system to the extent they are utility-scale and proven technologically and financially feasible.