Nebraska's First Wind Facility Coming Back to Life with New Direct-Drive Turbines at Springview
By Ainsworth, Star-Journal
Two, new direct-drive turbines were installed this summer by Bluestem, LLC, based in Omaha, which owns and operates the turbines. Bluestem, LLC, signed an agreement in November 2010 for a power purchase agreement with Nebraska Public Power District, officially bringing the site back into operation.
The two turbine towers were manufactured by Katana Summit in Columbus, the first Nebraska-built towers used on a wind facility in the state.
The two 1.5 megawatt direct-drive wind turbines are new technology in the design of utility-scale wind turbines.
Direct-drive wind turbines are significantly different than the wind turbines used at NPPD's Ainsworth Wind Energy Facility and other wind farms in Nebraska. Direct-drive turbines do not use a gear box, which is a major component used to increase the rotation speed of the large rotor to several hundred revolutions per minute for the generator. For this new technology, electric inverters are used to synchronize the generator into the grid versus using gearboxes.
The two turbines are the Vensys 77 model with the rotor (includes the blades and hub) diameter being 252 feet with hub height at 213 feet. The blades and rotor weigh 38 metric tons, the tower structure 90 metric tons, and the generator 42 metric tons. A total of 300 yards of concrete was used in the pad mounts for each tower.
Rotor speed is 17.5 revolutions per minute, and the wind speed rated output for the turbines is 29 miles per hour.
The power purchase agreement is for 20 years, with NPPD purchasing the electric energy produced by the turbines and sharing with Omaha Public Power District, Lincoln Electric System, Municipal Energy Agency of Nebraska and the City of Grand Island. Bluestem, LLC, is responsible for maintenance of the turbines. Energy generated from the two turbines is interconnected into the Ainsworth-based KBR Rural Public Power District electric distribution system.
The original turbines at Springview began operation in 1998 as a demonstration project to verify turbine technology available at that time, and to prove the efficiency and reliability of wind energy at distribution voltages in Nebraska.
Energy production data from wind turbines in the state can be found at the Energy Office website.
In 2007, after nearly 10 years of operation, the two 750-kilowatt wind turbines at the Springview Wind Energy Facility were retired. Lack of available replacement parts, significant maintenance issues as the units aged and the opportunity to sell the turbines at an attractive price, were the prime reasons for the decision to retire the units. The equipment was eventually sold to FPL Energy LLC, of Juno Beach, FL.
Information on other advanced renewable energy projects funded under the American Recovery and Reinvestment Act are listed at the Energy Office website.