Tri-State responds to Rocky Mountain Institute report on resource planning

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Aug. 23, 2018

  • RMI study lacks detailed inputs and complex models to forecast resources and costs
  • Environmental group invited to participate in 2019 integrated resource planning process
  • Association forecasts one-third of energy consumed to be renewable by year’s end
  • Tri-State currently soliciting for additional renewable energy supply

A high-level report by the environmental advocacy group Rocky Mountain Institute on future resource scenarios for Tri-State Generation and Transmission Association cannot accurately forecast the association’s future costs, said the not-for-profit power supplier to 43 member systems in four western states. Tri-State encourages RMI to engage in its public process for the next round of the association’s integrated resource planning, which is scheduled in 2019.

RMI’s case study does not have the detailed inputs, complex models and technical expertise necessary to forecast the association’s future costs. Tri-State’s resource planning process factors in the resources, loads across 43 member distribution systems, transmission constraints, reliability factors, and resource and fuel costs to credibly forecast and compare resource scenarios.

“The RMI report does not equate to the thorough resource modeling in our integrated resource planning,” said Lee Boughey, sr. manager, communications and public affairs. “We encourage RMI to suggest scenarios and engage in our inclusive public process next year.”

“Utility resource modeling is complex in scope, and no regulatory body, including our association’s board of directors, would substitute the RMI analysis for proper resource planning,” said Boughey. “We build resource scenarios, including those suggested by the public, and then run models on an hour-by-hour basis over a period of many years to understand how costs and reliability are affected.”

Tri-State adding renewables, retiring coal units

Tri-State’s resource portfolio continues to diversify as new renewable projects are added and coal units are retiring.

“Tri-State’s renewable portfolio can power the equivalent of a half a million rural homes,” said Boughey. “Still, we recognize the important role for other resources, including our coal resources, to ensure reliability and deliver low costs.”

Tri-State has added 475 megawatts of renewable resources since 2008, and the association’s members have another 140 megawatts of local renewable projects in place or under development. At the end of 2017, 30 percent of the energy consumed within the association came from renewable resources. Tri-State forecasts that renewable energy will grow to one-third of energy consumed within its membership by the end of 2018. The association is currently soliciting for additional renewable energy supply, and has received more than 100 proposals totaling over 10,000 megawatts.

“Tri-State already takes advantage of the current low costs of market power and renewable resources,” said Boughey. “We blend these market opportunities in with our owned and contracted low-cost resources to deliver reliable, affordable power to our members.”

Tri-State retired its capacity in San Juan Generating Station in New Mexico at the end of 2017, and will retire Nucla Station by the end of 2022 and Craig Station Unit 1 by the end of 2025.

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