Xcel urges quicker grid project construction to support 600-MW wind project

Public Service Co. of Colorado representative Betty L. Mirzayi told the Colorado Public Utilities Commission in July 8 testimony that the commission needs to bring forward by three years, to 2017, the allowed construction start on a a grid project that is needed to support the utility’s 600-MW Rush Creek Wind Project.

The commission in April 2015 approved the Pawnee–Daniels Park 345 kV Transmission Project for this Xcel Energy (NYSE: XEL) subsidiary. The project was approved as necessary to alleviate existing constraints on the company’s transmission system. In granting the application, the commission ruled that construction could not begin until May 1, 2020.

But Mirzayi, the Manager of Transmission Planning, said in the July 8 testimony filed in the Rush Creek docket that a feasibility study for the 345-kV Rush Creek Project shows that network upgrades are necessary to deliver the full 600 MW of output from Rush Creek I and II to the grid as a network resource. The study also shows that the Pawnee–Daniels Park Project will provide those necessary network upgrades. Accordingly, Public Service has filed a variance request asking the commission modify the construction schedule for the Pawnee-Daniels Park Project to result in an in-service date of Oct. 30, 2019.

Wrote Mirzayi: "I continue to recommend the Commission grant Public Service’s request to accelerate the Pawnee-Daniels Park Project construction schedule to allow construction to begin in 2017, for an in-service date of October 30, 2019."

The proposed construction schedule of the Pawnee–Daniels Park Project will proceed in several segments. Completion of the Harvest Mile Substation and the in-service date of that substation at the end of 2018 will benefit customers by providing Public Service the opportunity to more quickly utilize a portion of the energy from the Rush Creek Project as a network resource, and also to allow the company to take advantage of the production tax credit, which will directly benefit customers through lower priced energy. Completion of the transmission line segments in 2019 will allow the full amount of Rush Creek Project output to be injected as a network resource on Public Service’s transmission system. This will allow the company to take full advantage of the production tax credit for customers and benefit all customers through allowing the full amount of lower priced energy to be injected on to the system.

The company’s feasibility study for the Rush Creek Wind Project identified three thermal constraints for adding 600 MW of wind generation from Rush Creek. Those constraints are:

  • The 345/230 kV transformation capacity at Smoky Hill substation due to single contingency outage of any one of the two 345/230 kV auto-transformers;
  • The Missile Site–Daniels Park 230 kV line for the single contingency outage of the Missile Site–Smoky Hill 345 kV line; and
  • The Clark–Jordan 230 kV underground line for several single contingencies, with the worst overload resulting from the single contingency outage of the Smoky Hill–Tollgate–Leetsdale 230 kV line.

The feasibility study concludes that “mitigation of all three thermal overloads due to the aggregate impact of transmission improvements comprising the [Pawnee-Daniels Park Project] is evident from the power flow analysis results.” In other words, the study shows that in order to provide the Rush Creek Gen-Tie Network Resource Interconnection Service, the Pawnee-Daniels Park Project must be completed.

Since the Pawnee–Daniels Park Project has already been approved and will provide the network upgrades necessary to accommodate the Rush Creek Wind Project as a network resource, there are no reasonable alternatives to accelerating the Pawnee–Daniels Project construction schedule, Mirzayi wrote. Any alternatives would require the construction of new and duplicative transmission facilities. Therefore, any alternatives are inferior to simply accelerating construction of a project already approved and found to be in the public interest.

Public Service applied May 13 at the Colorado commission for permission to develop, own and operate as utility rate-based property a new 600-MW (nameplate) wind facility, which is made up of the Rush Creek I and Rush Creek II sites. In addition, Public Service requested two Certificates of Public Convenience and Necessity for the Rush Creek I and II wind facilities, and also to construct and operate a 345-kV generation intertie. 

The Rush Creek Wind Project is located on the eastern plains of Colorado. It is primarily comprised of two generation sites (Rush Creek I and II) and the 345 kV Gen-Tie. The Rush Creek I site, hosting a project to be rated at 400 MW, is about 75,000 acres located in Elbert County, southeast of Limon, Colorado. The Rush Creek II site, rated at 200 MW, consists of around 41,000 acres in Lincoln, Kit Carson, and Cheyenne counties, east of Hugo, Colorado.

In total, the Rush Creek Wind Project will include 300 Vestas model V110 wind turbines. The Rush Creek Project will interconnect to the grid at Public Service’s existing Missile Site Substation in Arapahoe County through the approximately 90-mile 345 kV Gen-Tie.

Public Service has requested expedited treatment of this application such that a decision of the commission is received on or before Nov. 10, 2016. This will allow the company to begin construction by the end of the year so that the 100% federal production tax credit (PTC) may be obtained. Rush Creek I and II are anticipated to be in service by Oct. 31, 2018.

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.