Tri-State Generation continues to grow its renewable energy portfolio

Tri-State Generation and Transmission Association said in an Integrated Resource Plan/Electric Resource Plan filed Oct. 30 with the Colorado Public Utilities Commission that it has added several new renewable energy sources to its power mix since 2010.

The period covered by this plan is 2016 through 2035. The plan evaluates both supply-side and demand-side resources on an integrated basis. Since 2010, Tri-State said it has implemented the following new renewable generation projects:

  • Colorado Highlands Wind – In February 2012, Tri-State signed a 20-year power purchase agreement with Colorado Highlands Wind LLC for the output and environmental attributes from a 67-MW wind farm located in northeastern Colorado. The project began operating in December 2012. In March 2013, Tri-State amended the power purchase agreement with Colorado Highlands Wind to reflect an expansion of the facility by 24 MW. The Phase II portion of the project began operating in September 2013, bringing the project’s total nameplate capacity rating to 91 MW.
  • Carousel Wind – In December 2013, Tri-State signed a 25-year power purchase agreement for a 150-MW wind farm to be built in eastern Colorado. Tri-State will purchase the entire output and environmental attributes from Carousel Wind Farm LLC when the facility achieves commercial operation in the spring of 2016. This agreement is Tri-State’s largest wind power purchase agreement to date.
  • Twin Buttes II Wind Project – In June 2015, Tri-State announced it had signed a 25-year power purchase agreement for a 76-MW wind project to be built in southeastern Colorado. The project will be owned by Twin Buttes Wind II LLC and is expected to be completed in late 2017.
  • San Isabel Solar – In August 2015, Tri-State signed a 25-year power purchase agreement with San Isabel Solar LLC for the output of a 30-MW solar project to be built in Las Animas County, Colorado. The project is expected to begin operations in the fourth quarter of 2016 and will be Tri-State’s first utility-scale solar project in Colorado.
  • Alta Luna Solar – In September 2015, Tri-State signed a 25-year power purchase agreement with TPE Alta Luna LLC for the output of a 25-MW solar project to be built in southern New Mexico. The solar project is expected to begin operations in the fourth quarter of 2016.
  • Tri-State Supported additional Member Distributed Renewable Generation – Tri-State members have the opportunity to invest in locally-developed projects to supply a portion of their power requirements under their wholesale contract with Tri-State. The number of megawatts operating or under development by Tri-State members has more than doubled since 2010 and over a third of Tri-State’s member systems have elected to support local distributed generation projects under Tri-State’s existing board policies. Currently, there are 48 such projects, totaling 73 MW of nameplate capacity and representing technologies including solar, wind, landfill gas, hydro, and recycled heat. Also,Tri-State’s financial support for these member renewable projects, in the form of over-market purchases of the renewable energy credits (RECs) associated with the projects, has significantly improved the economics.
  • Small Hydro Power Purchase Agreements – Since its last IRP/ERP, Tri-State has entered into several power purchase agreements for the output of small hydroelectric projects located throughout its member system service territory. These include an extension of the power purchase agreement for the output of the 5.6-MW Vallecito Hydroelectric Project near Durango, Colorado, and new contracts for the output from the 8-MW Tri-County Water Hydropower Project in Ridgway, Colorado, the 5-MW Boulder Canyon Hydroelectric Project located west of Boulder, Colorado, and the 2.9-MW Garland Canal Hydroelectric Project located in northwest Wyoming.

When assessing Tri-State’s system with a median load forecast, Tri-State projects a need for additional capacity by 2021 (2023 using the updated 2015 load forecast). For the ERP, various scenarios were developed to project the timing and preferred technology of the resource(s). Using current projections for key variables such as the price of natural gas, load growth, the cost of renewable generation, and capital costs for new conventional and renewable generation, the planning models consistently indicate that the preferred resources for the planning period will be a combination of natural gas and wind generation and demand-side resources.

Tri-State said it is positioning itself to have viable options to meet future needs that will include various alternatives such as natural gas-fired generation, renewable generation and demand side resources. No decisions have been made at this time as to the timing, technology, magnitude or location of new generation projects.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.