Mar 13, 2017

Sustainable: Organizations warming to geothermal energy

Margaret A. Cargill Philanthropies (MACP) last year celebrated the opening of a 66,777-square-foot addition that included a geothermal exchange system for heating and cooling office space.


Finance & Commerce

March 7, 2017
Frank Jossi

Margaret A. Cargill Philanthropies (MACP) last year celebrated the opening of a 66,777-square-foot addition that included a geothermal exchange system for heating and cooling office space.

MACP is one of a handful of organizations in Minnesota that have installed geothermal systems over the last few years. Although geothermal exchange systems require a significant upfront investment, the equipment generally lasts for decades and the fuel source, the Earth, costs nothing.

Geothermal exchange systems employ plastic tubing buried in the ground or placed in water to capture the Earth’s steady temperature by circulating a nontoxic liquid that transfers heat to and from the ground. The liquid passes into heat pumps, which through a refrigeration cycle concentrate heat in winter and cools it in summer.

The system at the Margaret A. Cargill Philanthropies office, 6889 Rowland Road, required drilling more than 140 well bores 250 feet deep to create a “vertical loop” connected to heating pumps. The system manages heating and cooling for the new addition while enhancing the performance of the previously existing 28,460-square-foot building, according to Shawn Kinniry, office and facilities manager.

“In the 10 months we’ve been in our expanded building, the system has operated efficiently, effectively, and according to design,” he wrote in an email. “By design, leveraging the Earth’s more constant ground temperatures, especially in this region where we have such wide temperature extremes, provides a jump-start of sorts” to maintaining appropriate temperatures in the building.

“It’s an incredible technology, it’s the technology of the future,” said Gary Connett, Great River Energy’s member and marketing services director. “There’s nothing greener, cleaner and more efficient than a heat pump.”

Many of the 28 members of Great River Energy, a wholesale electric cooperative, give customers rebates for installing geothermal exchange systems. Within Great River’s territory, the systems have installed in 12 schools, a number of churches, civic buildings, and “a few thousand houses,” Connett said.

Karges-Faulconbridge Inc., 670 County Road B W. in St. Paul, worked on the MACP project and several others involving geothermal systems. The engineering company’s own office building has a geothermal exchange system attached to a loop underneath a field next to its parking lot.

The office was a former grocery store built on a site that once served as a city garbage dump, according to Karges-Faulconbridge principal Randy Christenson. Geothermal made sense both as a way to demonstrate the system to clients and to economically manage the office temperature, he said.

Geothermal takes the heat of the earth, roughly 48 degrees in Minnesota, and uses that as a starting point for temperature control inside buildings. “You’re using the Earth, with a constant temperature, for storing heat in the ground in summer and pulling heat back out in winter,” he said.

Challenge and opportunity

One challenge facing the geothermal market today is low natural gas prices, he said. There’s little incentive for geothermal heating when a more traditional way, such as natural gas, is so inexpensive. When Christenson worked with the Alexandria school district recently, he suggested its desire for geothermal, while noble and sustainable, would take decades to pay back.

That hasn’t been the experience of all geothermal uses. The Margaret A. Cargill Philanthropies system should pay off in 13 years, Kinniry said. by comparison, a 112-kilowatt solar array installed at the same time on the new addition will take 80 years to exceed its return on investment, he said.

There’s also the idea that geothermal makes sense when an organization has aggressive sustainability goals. “We see this building component as mission-related, Earth-friendly, and sustainable, so monetary payback is again only part of our design story for this design element,” he said.

Jeff Beiriger, executive director of the Brooklyn Center-based Minnesota Geothermal Heat Pump Association, said geothermal energy is three to four times more efficient than traditional systems, such as boilers, and reduces energy use from 40 to 70 percent.

For building owners who know they are not leaving for decades — such as schools and universities — the heavy upfront cost can be paid off over time, Beiriger said. Zoned heating and cooling, which allows users to control temperatures in defined areas of an office or plant, is also simpler to create in a building with a geothermal system, he said.

Low natural gas prices aren’t the geothermal industry’s only challenge. When the U.S. Congress extended tax credits for wind and solar last year, it did not do the same for geothermal. The 30 percent tax credit certainly helped sales, Beiriger said, but future changes to the tax code, depending on what they are, could potentially jump-start the industry again.

Where geothermal works

While geothermal energy’s upfront cost may not work for every Karges-Faulconbridge client, there are those willing to make the investment to meet sustainability goals. MACP is one such client, even though its side required a few innovative strategies for the system to work.

The Philanthropies had to drill bores to install piping in a wetland it owns, for example. The city of Eden Prairie and the Nine Mile Creek Watershed District gave their approval for drilling in the wetland, which ending up with 40 percent of the drill bores. The rest surround the perimeter of the new building.

While the bottom line mattered, the organization saw geothermal exchange as a way to have a smaller environmental footprint.

“The chance to install a system that is more efficient than conventional heating and cooling systems, and leverages sustainable, Earth-friendly resources, is an opportunity that resonated very strongly with our organization’s leaders,” Kinniry said.

St. Paul-based Presbyterian Homes & Services installed geothermal heat exchange systems at two senior housing communities.

At Carondelet Village on the campus of the St. Catherine University, the project came about because the Sisters of St. Joseph of Carondelet wanted to make the community “an eco-friendly,” said John Mehrkens, vice president of development at St. Paul-based Senior Housing Partners, a subsidiary of Presbyterian Homes.

The organization installed geothermal to the three-building Folkestone in the Promenade of Wayzata, 100 Promenade Ave., because the structure rests on pilings. Placing the piping into the concrete pilings added only an “incremental cost” to the 253-unit senior community, Mehrkens said. Moreover, he felt comfortable that the technology of heat pumps, more commonly used in the South, would be able to handle Minnesota Winters.

He added that geothermal makes better financial sense for owners not looking to sell anytime soon.

“As a long-term owner of these properties, we have a little different perspective,” Mehrkens said. “We can look at that return over 30 years rather than five years that might happen if you were a developer building a project.”

Perhaps the state’s largest geothermal head transfer system is at Great River’s Maple Grove headquarters, 12300 Elm Creek Blvd. The bottom of Arbor Lake, behind the building, holds 36 miles of piping that feeds into 72 heat pumps. It shows the advantages of geothermal heat transfer to cooperative members, Great River’s Connett said.

He’s a huge fan of the technology. Natural gas prices will eventually rise and make geothermal more attractive, he believes, and more businesses and homeowners will see it as a way to reduce their carbon footprints.