Wind Turbine

Why did Luther College decide to construct a wind turbine?

As a charter signatory to the American College and University President’s Climate Commitment (ACUPCC), Luther College committed to reduce campus greenhouse gas emissions by 50 percent by the 2014-2015 school year and, ultimately, achieve carbon neutrality.  Generating and consuming renewable energy is one method to help achieve this goal. Luther purchased a 1.6 megawatt General Electric XLE wind turbine. 

How much electricity will it produce?

The electricity from the turbine will serve Alliant Energy's customers on the west side of Decorah, including Luther College.  The 5.2 million kilowatt hours of net electricity generated per year are enough to power more than 500 homes in Decorah and represents approximately one third of Luther's annual consumption.

 

How does the electricity generated by the wind turbine get to campus?

To protect the beauty of the natural environment, the transmission line for the project has been installed underground, carrying the wind-generated electricity under Highway 52, along Valley View Drive, under the Upper Iowa River near the Luther radio tower, and then east to the Alliant Energy distribution line that serves the Luther campus.

How much did this project cost?

~$3.3 million

Where did the money come from to pay for this project?

Luther College made a $1,150,000 cash investment in the project.  These funds were set aside over several years and primarily came from budgeted plant reserves.  In order to qualify for various state and federal incentives, the turbine project is being constructed under the auspices of Luther College Wind Energy Project, LLC (LCWEP).  Formed in 2005, LCWEP is a limited liability corporation that is eligible for Iowa's 476C renewable energy production tax credit.  The US Department of Agriculture has awarded LCWEP a $500,000 grant and a $1.3 million guaranteed loan under their Rural Energy for America Program.  The project will also make use of a renewable energy grant from the U.S. Treasury Department.  Financing is being provided by Decorah Bank & Trust and the Iowa Energy Center's Alternative Energy Revolving Loan Program.

How much money will the wind turbine save Luther each year?

The project has a 9-10 year payback.  In addition, it is projected to save the college at least $3 million in electricity costs over the 20-year life span of the turbine.

When was the wind turbine erected?

The wind turbine was fully erected on  September 19, 2011.  It took approximately five days to erect the turbine.

How was the location of the wind turbine decided?

The turbine is being constructed on a tract of land Luther is leasing from a private landowner under a long-term lease agreement  The site was selected because professional studies determined it has one of the best wind resources near the Luther campus.   In addition, the site is close to the electrical distribution line operated by Alliant Energy that serves Luther College and the west side of Decorah.  Situated directly across from the Dahl Centennial Union, the turbine is in view of the campus and thus helps make students and the community more aware of the potential of renewable energy.

Luther College rejected other proposed sites for a number of reasons.  A Pole Line Road site was ruled out because there was concern the turbine would cause shadow flicker problems for nearby homes.  A site in Roslien Woodlands on the northwest edge of campus would have required the removal of many trees to build the road to the site.  Research on potential sites 3-4 miles from campus showed that the wind resource was no better, and the cost to bring the power back to Alliant's line on the west side of Decorah would have been prohibitive.


When did the wind turbine start operating?

The turbine was commissioned by General Electric in late October and commenced commercial operation on November 1, 2011.

Why does the wind turbine periodically stop moving?

When wind speed drops below 2.5 meters per second, the turbine shuts down.  Other stoppages will occur for scheduled maintenance every six months or so. 

What environmental benefits does the wind turbine have?

The amount of renewable energy the wind turbine produces will reduce Luther College’s greenhouse gas emissions by approximately 3,000 metric tons per year.  The turbine will enable Luther to reduce its campus carbon footprint by another 14-15 percent.  

How do wind turbines generate electricity?

Click here for a short video explaining the process.  This is a wind map of the United States.  Here is another video of the completed turbine.

How often do the blades rotate per minute and how fast are they turning at the tip?

The blades rotate between 9 - 18 rpm, with a max tip speed of 172 mph

How does the wind turbine move to face different directions?

Luther's wind turbine is classified as a 'down-wind' turbine.  This means that the blades spin when wind is blowing directly at them, or when the turbine is facing into the wind.  Because wind changes direction from day to day, the blades also need to be able to change direction in order to work best.  A  weather vane on top of the nacelle, the gearbox mounted on the tower, measures wind speed and direction.  Using this information, the nacelle uses a series of gears housed in the tower to rotate into the wind.

Where was the turbine manufactured?

All of the components of the turbine were made in the U.S.  The tower was manufactured in California, the nacelle in Pensacola, Florida and the blades in Newton, Iowa.

What impact does wind power have on birds?

Birds can be killed when they fly into blades or towers of wind turbines, and their habitats can be fragmented or other-wise affected by turbine sites and service roads.  Studies show that an average of 145,000 birds are killed by the U.S. wind industry each year.  However, a 2005 study by the U.S. Forest Service found that 550 million birds die each year from colliding with buildings.

And wind power can help reduce the most significant threat birds face: global warming, which damages animal habitats and food supplies.  A 2004 study estimated that if heat-trapping emissions were to continue unabated, approximately one million species (including birds) could become extinct by 2050. To learn more, visit www.awwi.org

Source: "What Impact Does Wind Power Have on Birds?" Earthwise 14.4 (2012).

Interesting Facts

  • It averts 2.5 million pounds of coal per year (100,000 cubic feet)
  • The nacel is the size of a mobile home (12' x 30')
  • The swept area is 268'
  • The height of the hub is 262'
  • The height to the tip of the blade (when pointing directly up) is 398'
  • It took 12 trucks to ship the crane
  • It took one week to prepare the crane and one week to erect the turbine
  • The foundation consists of 400 cubic yards of concrete, or 50 truck loads
Luther's GE XLE Turbine being assembled
Wind Turbine
Wind Turbine