Geothermal technology has been around for decades, it works, and it’s increasingly affordable. At colleges that must maintain dozens of large buildings, the savings are magnified.

Those involved in the decision to pursue geothermal technology say they wanted to use less coal-fired power, although the schools also had to save money to justify the move.

The technology is a natural fit for schools like Boise State that sit atop geothermal springs. The school recently announced it expects to save as much as $80,000 per year in heating costs by doing so, and even more as the project expands.

Yet schools in the Midwest and East are also turning to geothermal power using a different type of technology.

A typical geothermal system works like this: On a warm day, the system draws heat from a hot building and pumps it underground where the soil absorbs it. On a cold day, the process reverses–the system extracts heat from the earth and returns it to the building.

The process is so efficient that even though the underground temperature remains about a constant 55 degrees, the system can be used to chill water to 45 degrees or heat it to 170 degrees.

"That makes heating and cooling a whole new ball game," said Robert J. Koester, a Ball State University architecture professor overseeing one of the nation’s most aggressive installations.

The Muncie, Ind., campus is upgrading all of its 45 buildings to geothermal technology, at a cost of $65 million to $70 million. The state contributed about $40 million, and because the system is expected to cut energy costs by $2 million per year, it should pay for itself in 12 to 15 years.

The savings won’t translate directly into tuition breaks, Koester said, but it will ease the school’s pressure to find funding for other operational expenses.

Students have been advocating for a shift in campus energy sources for years. The increased investment in geothermal comes as students launch a national campaign intended to pressure schools into using less energy from coal-fired power plants. Students began protests late this year, specifically targeting 60 campuses that have their own coal-burning power plants.

There are several variations of geothermal installations. A common version involves drilling a series of holes, each about as wide as a beer mug, to a depth of 300 to 400 feet. An electrically powered compressor and fan help distribute the heat into and out of the holes.

The University of Wisconsin-Madison, which spends about $50 million in climate-control costs per year, is incorporating a geothermal system in a building that opens next fall. The school should recover the $1.25 million cost in 15 to 20 years, said George Austin, the building project manager.

"If energy costs rise at a rapid rate, the payback [time] may be less than that," he said.

That is another advantage that colleges have when it comes to geothermal energy. In some cases, it can take years to recoup the costs of a geothermal system, and most schools hash out budgets years or decades into the future.

However, the technology might not be the best choice for every school.

Urban schools might not be spacious enough to install the pipes where they can be accessed easily for maintenance and repair, said William C. Johnson, a board member at Second Nature, a Boston-based nonprofit that focuses on sustainability in higher education.

There can also be unforeseen regulatory issues that can drive the initial cost higher, which officials at the Theological Seminary in New York City blame for tripling their price tag.

The initial estimate of $6 million to upgrade 18 buildings ballooned to about $20 million, to be paid over five to 10 years, said Maureen Burnley, the seminary’s executive vice president.

"We’d still do it again, though," Burnley said.

With just five buildings upgraded so far, the seminary has already saved about $200,000 in heating and cooling costs last year.

Links:

Energy Department’s Geothermal Technologies Program

Second Nature