Imperial County, California, USA
Pattern Energy Group
The Ocotillo Wind Project located in Imperial County, California, was developed by Pattern Energy Group and comprises of 112 wind turbines. The project is spread across 12,346 acres and generates 265MW of power.
The project produces clean and renewable wind energy that is sufficient for more than 130,000 southern Californian households each year.
The project created 350 jobs during peak construction period and 20 permanent positions during operations. It also contributed significantly to the local economy’s tax revenues.
A rotor blade of one of the turbines fell off in May 2013 causing the turbine operations to be temporarily suspended. The operations were resumed two months later.
Ocotillo wind project details
The Ocotillo wind farm is spread over 5,058ha of land, most of which is federal land administered by the Bureau of Land Management.
In November 2012, 94 turbines generating 223MW of electricity commenced commercial operations. The remaining 18 turbines with 42MW capacity came on stream in July 2013.
Ocotillo wind farm construction
Blattner carried out the main construction activities for the project, which included building the roads, digging foundations for concrete pour to install the turbine towers, trenching for the electrical system, and installing the wind turbine generators.
An electrical substation and Operations and Maintenance (O&M) building were also constructed at the project site.
Turbine technology used at the Ocotillo wind project
The turbines used at the Octotillo wind farm have a power rating of 2.37MW each. The turbines incorporate state-of-the-art aero-elastic blade design by Siemens. They have longer blades designed to produce more energy even during moderate wind conditions.
Each turbine has a 108m diameter rotor and pitch regulation that not only enhances power output but also controls energy output. The turbine blades are mounted on cylindrical towers with a hub height of 8m. The blades are self-supporting, 53m-long and have a root chord of 3.4m.
The horizontal axis rotor has three blades in upwind position sweeping an area of 9,144m2 at a speed of 6rpm to 16rpm.
Transmission of power from the Ocotillo wind farm
Pattern Energy signed a power purchase agreement (PPA) with San Diego Gas & Electric (SDG&E) for the sale of energy produced by the project for 20 years. As per the agreement Ocotillo Wind Project will transmit energy through the newly constructed Sunrise Powerlink. The 117 mile transmission line links San Diego and the Imperial Valley.
Financing for the Ocotillo renewable power project
Pattern Energy achieved financial closure of the Ocotillo project in October 2012. A structured construction loan with a commercial tranche of seven years was granted by Deutsche Bank and RBC Capital Markets, while North American Development Bank provided a 20-year tranche loan.
Other key financiers for the project include The Royal Bank of Scotland, Société Générale NORD/LB and KeyBank.
Contractors involved with the Ocotillo project
The construction contract of the project was awarded to Blattner Energy. Siemens supplied 112 SWT-2.3-108 wind turbines under a contract that covered delivery, technical field assistance and commissioning. The contract also includes a two-year service and maintenance agreement.