For many people, geothermal energy conjures up images of steaming geysers or bubbling hot water gushing up from superheated rocks deep within the Earth. The western United States is rich in this form of energy, but in the East, these heat-producing layers are too deep to be retrieved without expensive exploration technology.
But geothermal also applies to the use of heat pumps that can create energy from the temperature difference between the surface of the Earth and the relatively stable subsurface temperature of approximately 50 degrees Fahrenheit at depths of about 10 to 300 feet.
Which is why Ball State University in Muncie, Ind., is installing the largest geothermal heat pump system in the country. The university estimates that the project, which broke ground on May 9, will save the school $2 million in energy costs a year while cutting its carbon dioxide emissions by a dramatic 50 percent.
The university hopes the project will raise public awareness of geothermal energy as an alternative energy source, in addition to its environmental and financial savings. "Geothermal, although people know the term, don't understand the term," said Jim Lowe, director of engineering and operations at the university.
"What we hope to accomplish through this is a better understanding of what geothermal is," he added.
'Little G' works where 'big G' can't
Direct-use geothermal heating is growing in the western United States, where hot temperatures are relatively near the surface. John Shonder, senior mechanical engineer at Oak Ridge National Laboratory, described this type of geothermal heat as "big G."
Geothermal, or ground-source, heat pump systems, such as the one Ball State University is installing, are known as "little G."
"What we're talking about here is 'little G'; [it] uses the Earth as a heat source and sink for air conditioning and heating," Shonder said, adding that most ground-source heat pumps serve single buildings rather than districts, or groups of buildings.
"The unique thing about Ball State is it's going to have wells that will serve various buildings and pump water all around campus," he said.
The university plans to drill 3,700 to 4,000 well holes on three well fields throughout the campus. Each well hole will measure 5 inches in diameter and will extend to depths of 400 feet below the Earth's surface. Loops of high-density polyethylene pipes will be inserted into the holes, forming two vertical closed-loop systems through which fresh water will circulate. Hot water will flow through one loop system and cold water through another. The loops will connect to buildings through heat exchangers and fans, which will regulate the building temperature depending on the season.
In addition to the three well fields, the school plans to install approximately 10 or more heat pump chillers in three energy centers located throughout the campus to move water through the system. The chillers will communicate with each other to supply adequate amounts of hot or cold water throughout the campus.
The heat pump chillers are essential to the system, Lowe said, explaining that they create cold and hot water simultaneously. Three chillers will use a closed loop of refrigerant, a liquid that boils at low temperatures, to move heat from a cooler area to a warmer one. The direction of heat transfer will depend on the season.
Once completed, the new geothermal system will heat and cool more than 40 of approximately 50 buildings on the 660-acre campus, according to Lowe, who expects the project will take five to eight years to complete. He hopes to remove two of the four boilers currently used to heat the campus within three years, and the final two by the project's completion.
Going 'green' and replacing oil boilers
Ball State University committed to becoming "climate neutral" more than two years ago when President Jo Ann Gora signed the American College and University Presidents' Climate Commitment. That created the need to reduce emissions in a cost-effective manner. The existing university heating system, which uses 60- to 70-year-old coal boilers and natural gas, needed replacing, Lowe explained. "Geothermal presented that opportunity," he said.
"The energy savings are significant, as well as the operating efficiency, so we're very excited about the project," Gora said during an interview.
The geothermal heating and cooling system will reduce the university's CO2 emissions by approximately 80,000 tons per year. Installing it is expected to create about 900 jobs, many of them in Indiana, according to Gora.
Gora said it is important that the Ball State geothermal project "shine a spotlight" on geothermal energy, which she believes has been held back by the fact that it is primarily used for single buildings rather than districts.
Gora said the school plans to apply for some of the funding allocated for geothermal energy development under the American Recovery and Reinvestment Act to help pay for its new geothermal system, which is estimated to cost between $65 million and $70 million.
President Obama earlier this week announced the availability of $350 million in Recovery Act funding for new investment in geothermal energy. The president committed more than $467 million to solar and geothermal research and development on Wednesday, marking 100 days since he signed the $787 billion stimulus bill into law.
In addition, the university has received approval from state officials to redirect $41.8 million in bond funds raised to replace Ball State's aging coal-fired boilers to go toward the geothermal project, according to the university.
More federal incentives may be on the way
While campuswide systems such as the one Ball State will build are rare, Karl Gawell, executive director of the Geothermal Energy Association, the industry's trade group, thinks projects such as this will spur other campuses and projects into action.
"People look at colleges and universities as a bellwether of where society is moving," Gawell said.
Gawell was initially disappointed when he saw Obama's fiscal year 2010 budget, in which the U.S. Department of Energy requested $50 million for geothermal projects, a $6 million increase from last year's budget. Most of this funding is earmarked for the development of long-term commercial technology, such as "enhanced geothermal systems," or EGS.
However, Obama's recent announcement that $350 million in stimulus funds will be made available for near-term as well as long-term geothermal research and demonstration projects signaled the new administration's willingness to consider a full range of geothermal resources and technologies, unlike the budget, according to Gawell.
The president's announcement is "really the first time we've seen a real clear indication of the direction of the Obama administration on geothermal," Gawell said.
"It's exciting to finally see it on paper, not just on paper but from the actual mouth of the president of the United States," he added.
DOE will funnel $140 million of the stimulus funding toward demonstration of technologies to advance geothermal energy in new geographic areas as well as geothermal energy production from oil and natural gas fields, geopressurized fields and low- to moderate-temperature geothermal resources.
The department will invest another $80 million in the research and development of EGS, which involves the use of a technology that injects water into deep wells drilled down to hot rocks within the Earth. The injected water turns to steam when it reaches the hot rock, which powers turbines to generate electricity.
Another $130 million will go toward geothermal exploration projects and a nationwide assessment of geothermal resources.
Although most of this funding does not apply to geothermal heat pump systems, such as the one Ball State is planning to install, Gawell said he was informed by "knowledgeable sources" that there will be a follow-up DOE announcement for an additional $50 million in funding to address several "issues," including geothermal heat pumps.
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