A Citizen-Powered Energy Grid in 2009: A Case Study in Geothermal

Categories: Renewable Energy
Posted on Monday, January 26th, 2009 at 12:46 pm by admin

The following is an excerpt from The Citizen-Powered Energy Handbook: Community Solutions to a Global Crisis by Greg Pahl. It has been adapted for the web.

Luther College, located in the small northeast Iowa town of Decorah, has two examples of successful, closed-loop, geothermal heat-pump systems. One is located in Baker Village, a student housing complex, and the other is in the college’s striking new Center for the Arts. Interest in geothermal systems on campus was initiated by a student environmental group, and eventually resulted in the installation of a 72-ton system in the 33,000- square-foot Baker Village complex. A large group of heat pumps ranging in size from 2.5 tons up to 5 tons located in various parts of the complex are connected via underground plastic piping to 88 vertical closed loops in 150-foot-deep holes bored in the ground. The closed loops are filled with a food-grade, biodegradable antifreeze solution that circulates and acts as the heat transfer medium. The two-story complex was opened in 1999, and provides housing for approximately one hundred students.

The Baker Village system was so successful that the college decided to use geothermal in its new Center for the Arts as well. Opened in April 2003, the two-level, 60,000-square-foot Center for the Arts is home to the college’s art and theatre/dance departments, and also contains a 225-seat theater, classrooms, a computer lab, darkroom, faculty offices, two art galleries, and a café. The 248-ton geothermal system includes 52 two-speed heatpump units ranging from 1 to 15 tons, connected to 86 wells bored to a depth of 300 feet. This geothermal heating and cooling system was the first to be installed in an academic building in Iowa. Although the system was initially more expensive to install than conventional heating and cooling systems, the college expects to recover the added investment in less than five years on account of lower operating and maintenance expenses.

“The two geothermal buildings have been part of an overall energy audit and conservation project that has been conducted by the college over the past two years,” says Jerry Johnson, the college’s director of public information. “Those buildings have played a major part in the reduction of the college’s energy use by around 12 percent compared to two years ago. Obviously, we’re very pleased with the performance of the geothermal systems in those buildings.” There have been no major operational problems with either system, and the transition for the college’s facilities staff was simple and easy, according to Johnson. “Incorporation of the Center for the Arts into the main campus in conjunction with our central heating system ent quite smoothly,” he says. “Anyone who has a multiple-facility complex like ours who is wondering how they would incorporate a system like this needs to know that it was not as challenging as they might think.”

Founded in 1861 by Norwegian immigrants, Luther is a four-year college affiliated with the Evangelical Lutheran Church in America. The college offers a liberal arts education leading to the bachelor of arts degree in sixty majors and preprofessional programs for its 2,600 students. Additional geothermal systems are likely at Luther. “If the college puts up any buildings in the future, I am certain that geothermal will be part of the design and operation of those buildings,” Johnson continues. “The college is currently conducting a capital campaign to build a new science building, and although the plans are not complete, I am sure geothermal will be part of that project too. We’ve been very happy with these systems.”

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An update from Luther College on its energy usage:

Luther College recently released the results of a carbon footprint analysis for the 2007-08 academic year. The data shows that Luther has reduced its campus carbon footprint by 15 percent.

The college’s greenhouse gas emissions peaked at 20,927 metric tons in the 2003-04 academic year. These emissions were reduced to 17,672 metric tons in 2007-08, primarily through a $1.5 million investment in energy efficiency.

The energy savings from these energy efficiency measures are enabling Luther to pay back this investment in less than seven years.

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