Spirit Lake School District Case Study

July 31, 2012

The Spirit Lake School District in Iowa installed a 250-kilowatt (kW) wind turbine in 1993 and a 750-kW turbine in 2001, providing an example of installed renewable energy for other schools across the nation to follow while offsetting approximately 46% of the district's electricity needs. The following case study summarizes the project's history, including cost, funding, and technical details.

250-kW Turbine

  • Spirit Lake School District paid $239,500 for its first turbine in 1993, which powers the elementary school. The district received a grant of $119,000 from the U.S. Energy Department and covered the remaining project cost via a low-interest loan from the Energy Council of the Iowa Department of Natural Resources.
  • The district made the final loan payment in 1998, 3.5 years ahead of schedule.
  • The Windworld turbine is 140 feet tall and has a 90-foot blade diameter.

750-kW Turbine

  • The district installed a second wind turbine in 2001 for a total cost of $780,000. The Iowa Energy Center's Alternative Energy Revolving Loan Program provided a $250,000 loan with no-interest financing. Spirit Lake also received a $580,000 loan from the Iowa Department of Natural Resources with a 5.1% interest rate.
  • The NEG Micon averaged nearly 83% of projected output in its first 5 years. The turbine's $120,000 in annual production exceeded the district's yearly loan payment amount of $93,000.
  • The district initially used the surplus revenue to pay down its 10-year loans but is now paying for other district expenses instead.
  • The 750-kW NEG Micon turbine is 180 feet tall with a blade diameter of 160 feet.
  • The district paid an annual fee of $5,000 for a service agreement with NEG Micon to cover all parts, labor, and scheduled maintenance expenses for the first 5 years of the project.

The turbines have required only two major repairs. First, the computers had to be replaced in 2003 following a lightning strike. School insurance covered all but $1,000 of the $4,400 expense. Second, the NEG Micon gearbox had to be replaced, but a warranty agreement covered the entire fee, which exceeded $50,000.

Spirit Lake School District Savings from On-Site Wind Turbines
YearSavings* $
1993$12,243
1994 $24,978
1995$25,007
1996$25,951
1997$20,185
1998$19,853
1999$23,969
2000$21,650
2001**$46,123
2002$137,798
2003$136,406
2004$150,420
2005$156,474
2006$129,987
2007$146,018
2008$132,776
2009$128,377
2010$163,515
2011$178,709

Source: Spirit Lake Community Schools

* These dollar amounts represent money the district did not have to use for utility bills; the money instead could be added to the general fund for other district needs.

**The district installed its second turbine in 2001.