Residential geothermal example. Photo courtesy of Bosch Thermotechnology.
By John P. DiEnna, Jr.
Geothermal heat pumps (GHPs) use the Earth’s thermal properties, (the energy under our feet) to provide heating and cooling for buildings, along with water heating. It has had more interest by governments, utilities, developers, and users in recent years than in the previous forty. The Environmental Protection Agency says the technology can reduce greenhouse gas emission by up to 40% over conventional HVAC systems. It is a far more effective way to use electricity than even air-source heat pumps. It can also reduce our dependence on fossil fuels, save water, and provide local jobs.
Governments are recognizing that this technology, which combines a renewable thermal asset (the ground loop) and an energy-efficiency product (the heat pump), can support a stronger grid, reduce peak load problems, lower emissions and provide their users more manageable energy bills.
In New York State, Governor Cuomo’s Clean Energy Plan recognizes the geothermal ground loops as a renewable thermal asset, making the technology fit very well with New York’s Reforming the Energy Vision initiative. GHPs are currently being considered by investor-owned utilities as resources in their distributed service implementation plans. GHPs can provide a “behind the meter,” non-wires alternative that can help stave off traditional capital expenditures, such as substation upgrades.
GHP technology has been used to advantage in other states. Western Farmers Electric Cooperative, in Oklahoma and New Mexico, developed a geothermal heat pump program that has seen the peak demand for HVAC in participating homes drop by 38%, or a reduction of 0.55 kilowatts (kW) per ton of installed capacity.
Schools across the country have tapped into the energy they already own to deliver a comfortable learning environment for their students while reducing their energy bills. Don Penn of Image Engineering has installed geothermal heat pumps in over 250 schools in Texas. Alderson Engineering, in Philadelphia, has designed numerous schools in Pennsylvania and New Jersey.
American Water, one of the largest private water companies in the U.S., in strategic partnership with Bosch has developed a state of the art geothermal pilot project in an elementary school built circa 1957, using their water as the medium for the geothermal heat pumps. This system is delivering year-round comfort and has enabled the school to use their facility through the summer. The GHP system has reduced their overall energy use by 30,000 BTUs per square foot.
We now recognize the water saving capability of GHP technology. A study on a 150-room hotel in Florida compared geothermal heat pumps with a water cooled chiller, and the results were dramatic. The GHP system saved 4,730,400 gallons in one year, reduced maintenance, and eliminated the chemicals needed for the chiller system.
The preliminary results of a recent study by Oak Ridge National Labs, outlining the potential for GHPs, showed that they could save 6.7 quads of primary energy, if they were used in every home and commercial building in the country. This would save 433.3 million tons of CO2 emissions and reduce energy costs in the U.S. by $80.4 billion annually, while reducing peak load and supporting a stronger grid.
The main barrier for increasing use of GHPs, and some think the only barrier, is the high initial cost of systems. The chief reason for that high first cost is in the installation of the item that makes this technology work, the loop field. We now see that resistance to this barrier is changing, as utilities, developers and third party investors see the long term value that loop field ownership has. The loop field can have a life span of over fifty years, making the initial investment a wise purchase.
We also need more trained installers. Although there are over 6,000 in the country we must develop the personnel resources to take fullest advantage of the technology. Widespread adoption of GHP technology could also mean the creation or retention of over five million jobs. The International Ground Source Heat Pump Association has developed the training and certifications needed to support the growth of geothermal heat pumps.
Mr. DiEnna is the Executive Director & Founder of the Geothermal National & International Initiative (GEO-NII). He has over forty years combined experience in the electric utility industry and the renewable energy industry and is a nationally recognized authority on geothermal heat pumps.
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