Twin Groves Windfarm
Located on the wind-swept Bloomington Moraine in eastern McLean County, Twin Groves Wind Farm offers 396 megawatts of affordable, pollution-free wind energy, enough to meet the annual energy needs of about 118,000 homes. The project supports the local economy through royalties to 140 landowners whose land spans over 22,000 acres -providing a cash flow that supplements earnings from farming. During construction, 350 jobs were created and presently, 37 full-time employees support current operations. Twin Groves also brings new jobs and substantial tax revenues to the county and local schools.
Project Fact and Figures
Location: McLean County
Acreage: 22,000 acres
Construction Completion Date:
Phase I: June, 2007
Phase II: February, 2008
Project Size: 396 megawatts.
Annual Power Generation: 1.3 billion kilowatt-hours.
Number of Turbines: 240 wind turbine generators, with a rated capacity of 1.65 megawatts each.
Why McLean County?
The wind resource in Illinois had long been considered mediocre, until a study conducted by the US Department of Energy and the National Renewable Energy laboratory identified several areas in the state that could be commercially viable wind sites, some located in central Illinois. The Twin Groves site is located in one of those identified areas, which makes it a perfect fit for development with its strong wind resource, excellent access to electricity transmission lines, good proximity to power markets, and its wide-open crop land.
Most people tend to think of Illinois as very flat, but in reality there are many gentle swells and broad valleys—perfect for wind energy development. These subtle ridges, hills, and long uphill slopes are easily overlooked when traveling through the state. The Bloomington Moraine, on which the Twin Groves project is developed, is one of the four largest moraines in Illinois and was formed during the Wisconsin glacial episode some 14,000 to 25,000 years ago.
Project elevations range from approximately 650 to over 900 feet above sea level. The project was constructed on farmland in the Arrowsmith, Cheney’s Grove, and Dawson Townships.
Initiatives in Illinois in 2001 and 2005 called for more of the state’s electricity to come from wind turbines and other renewable sources. In August 2007, Illinois enacted legislation to create the Illinois Power Agency charged with competitively procuring energy supply and meeting a renewable portfolio standard of 25% by 2025. According to the act, a minimum of 75% of the renewable energy must come from wind power.
The McLean County Zoning Board adopted several zoning changes to formalize the requirements for wind turbines. The changes included set back and height limitations. Horizon maintains a minimum distance of 1,500 feet from any residence.
Based on average EPA-reported 2004 emissions rates, a 390-megawatt wind farm would displace annually:
• 1,880,000 pounds of NOx.
• 4,800,000 pounds of SO2.
• 700,000 tons of CO2.
• 50,000 pounds of mercury.