When Russ Gohl built his new house in Minot last year, he went for all the energy conservation he could get. His plan included a geothermal system that provides for his heating and cooling needs.
"It's the thing of the future," he said. "As energy costs continue to rise and rise and rise, I was more interested in controlling them now than pay for them later when I am on a retirement income. I am looking at this more as a long-term investment."
Geothermal systems present a larger expense upfront, but industry experts say the payback can occur in as little as two to 10 years.
The use of geothermal energy and ground-source heat pumps have grown in popularity in recent years as people look for ways to hold down the cost of heating and cooling and save on fossil fuels. Interest has been particularly keen in this area among owners of commercial buildings.
One of the largest systems belongs to Investors Real Estate Trust. Its new retail and apartment building at Dakota Square uses geothermal heating for most of its heating and cooling needs. The system uses 175 wells that are 300 feet deep, 20 miles of geothermal pipe and 118 pumps to service 215,000 square feet.
Dave Pankow, director of risk management and construction services for IRET, said the company decided to use the property as a test, with the possibility of including geothermal heat pumps in its future construction if the cost-benefit is there.
"Since we are long-term holders of property, we are constantly looking for avenues to decrease our operating expenses," he said.
The payback is expected to be better than the typical residence because of the presence of the retail component, he said. At times, commercial space can demand cooling even in the winter. That means the geothermal system in the winter may return some heat into the ground, where it will become available for warming the 71 apartments.
The apartments opened Jan. 19 and the commercial portion opened in April. It appears that tenants are incurring very reasonable heating bills, Pankow said. He added that the system has kept the building comfortable while managing the varying demands placed up on it, from keeping snow and ice off a vehicle ramp when it's 40 below to keeping a sensitive data room cooled to the proper temperature.
A rough estimate shows September heat costs were 9 cents a square foot, compared to 14 cents a square foot in IRET's former building downtown. The company plans a more detailed analysis once it completes it first year with the system.
Souris Valley Dental is using geothermal energy on a smaller scale in its building constructed in 2006 in south Minot.
"It was suggested to us by our builder as well as our mechanical engineer," said dentist Mark Hildahl. "It's a little bit of an investment up front, but over time it pays for itself in savings."
A study by Verendrye Electric Cooperative showed the 5,500 square-foot main floor and basement could be heated and cooled for an average of $200 a month. The payback time on the system's installation is estimated at three to five years.
Hildahl said the energy savings is always a goal, but installing a geothermal system also is important to keep up with the times.
"We just thought it added value to our building for the future," he said.
As one of a number of area homeowners installing geothermal systems, Gohl estimates he is paying 80 percent less than he once did for energy, even though his new home is much larger than his former house. The savings is due to the home's high insulation factor and the geothermal system, which includes 14 wells going down 200 feet. He also has a roof-top wind generator and uses fluorescent and LED lighting.
His geothermal system operates his hot-water heater, too. During the cooling season when heat from a home goes back into the geothermal system, hot water becomes essentially free. During the heating season, hot-water costs are reduced.
Gohl's system is one of about 80 geothermal heat-pump projects designed by Prairie Engineering of Minot in the state. The list includes schools, churches, hotels, government buildings, banks and assisted living centers.
The company uses a sophisticated computer program to analyze inputs such as ground temperature, conductivity of soil, design of the heat pumps and a buildings' heating and cooling needs to aid in determining a system's configuration.
North Dakota's climate is a good fit for geothermal because the heat pulled out in the winter is restored during the summer, enabling the ground temperature to stay fairly constant on average, said Lon Drevecky with Prairie Engineering. In this area, ground temperatures stay around 45 to 47 degrees, regardless of air temperature, he said. Parts of the country that rely largely on heating or cooling alone can experience thermal pollution underground.
Drevecky said geothermal systems are becoming more common as contractors get more familiar with them, more manufacturers make better equipment, more well drillers get certified and prices come down. The systems are attractive to people conscious of energy costs, too, because the efficiency of heat pumps enables people to get 3.4 kilowatts of energy for every kilowatt of electricity used by the pumps, he said.
"Any new buildings that go up now that don't use heat pumps are short-changing themselves really in the future and right now," said Larry Johnson, engineer with the Minot Air Force Base's 5th Civil Engineer Squadron.
Johnson is one of the region's biggest proponents of geothermal. He's been instrumental in the conversion of many buildings on the base as well the incorporation of systems into design of new buildings.
By the end of 2010, the base should have 1,500 to 2,000 wells on the base and at missile sites, Johnson said.
All the new dormitories on base and bomb wing headquarters have geothermal systems, and the engineering headquarters is in the process of conversion. A new police station under construction will use the system, as will any new construction going forward, Johnson said.
The 15 missile alert facilities are in line for conversion, possibly in 2010. Two more dorms and a new dormitory being built in 2010 or 2011 also are next.
The Pride building on base is using a new twist on geothermal that transfers heat energy from cold water lines to the hot water lines inside the building. In instances where there is too much heat or cooling, the excess goes into geothermal wells. The system already has worked successfully in another base building about a quarter of the size of the Pride building.
Johnson even retrofitted his own house in Minot to use geothermal energy. The system uses just four wells, 200 feet deep.
"The biggest problem with heat pump systems is that there's too much overkill," Johnson said. "I would say 75 percent of the systems that go in are oversized, and that runs the cost up a great deal and makes the payback really hard to do."
Johnson said people interested in ground source heat pumps need to make sure they get an accurate heat-load analysis on their buildings to ensure the design is appropriate.
