The Shannon wind farm is equipped with 119 wind turbines. Credit: Madmick99 on FreeImages.
Electrical installation works for the project were performed by Mortenson’s power delivery group. Credit: M A Mortenson company.
Preliminary construction works for the Shannon wind farm commenced in 2013. Credit: M A Mortenson company.

The 204MW Shannon Wind farm in Windthorst town, Clay County, Texas, US, is jointly owned by Alterra Power (50%) and an affiliate of Starwood Energy Group (50%).

Alterra Power acquired the project from Horn Wind in February 2014, while an affiliate of Starwood Energy Group acquired a 50% interest in the project from Alterra Power in June 2015. Alterra Power is responsible for the management of the power plant.

Construction of the onshore wind power project in Texas commenced in January 2015, and the plant started commercial operations in December 2015.

The output from the power project is sufficient to provide clean energy to more than 61,000 Texan households. The project created more than 250 jobs during the construction phase.

Shannon wind farm make-up and grid connection details

The Shannon wind farm is located on a 17m² site and is equipped with 119 General Electric (GE) wind turbines, which have a rotor diameter of 103m and are rated at 1.7MW each.

Output from the wind turbines is conveyed to a 345kV, onsite single transformer substation via a ten feeder, 40 mile-long underground collection system, and further conveyed via a 345kV single-circuit, double-bundled transmission line to a substation owned by Oncor Electric Delivery company, the biggest transmission and distribution utility in Texas.

Shannon wind project construction

Foundation excavation works and site road construction, as well as the start of manufacturing for the wind farm’s transformer were initiated prior to the start of main construction works, to allow the project to qualify for the US production tax credit.

Construction of the site access road, turbine foundations and collector lines were completed by June 2015. Delivery of the wind turbines commenced in June 2015 and turbine installation works were initiated in July 2015.

Contractors involved

The engineering, procurement and construction (EPC) contract for the wind power project was awarded to Mortenson Construction in May 2015. The same company also performed preliminary construction works for the project in 2013 and 2014.

GE, who supplied turbines for the wind farm, is also responsible for providing operations and maintenance services for the turbines under a long-term contract. The main power transformer at the site was manufactured and installed by Siemens.

Financing for the Clay County wind farm

“Construction of the onshore wind power project in Texas commenced in January 2015, and the plant started commercial operations in December 2015.”

The project received a $287m construction loan facility in June 2015, which included a $212m loan and $75m in letters of credit granted by affiliates of Citibank, Santander and the Royal Bank of Canada.

The loan was supported by a $219m tax equity investment commitment provided by subsidiaries of Citicorp North America and Berkshire Hathaway Energy.

Power purchase agreements

The majority of power produced from the Shannon wind farm is sold to Citigroup Energy under a 13-year contract.

In July 2015, Facebook announced it will power its upcoming data centre in Fort Worth, Texas, with renewable energy from the Shannon wind farm.

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