Plugging Into the Earth
- By Sarat Pratapchandran
- October 1st, 2010
Despite a slow start in its early days, more school districts are embracing geothermal technology as a viable source of energy to power their school buildings. A growing interest in renewable energy, cost savings and popular sentiment against dependence on foreign oil is swaying communities and school boards, mostly in the Southwest, to opt for geothermal energy sources.
“We are seeing more school districts embrace geothermal technology,” says Don Penn, president of Image Engineering Group (IEG), a Texas-based geothermal energy consulting firm that has installed over 160 geothermal heat pumps (GHP) nationwide.
“Schools are definitely more receptive than they were 10 or 15 years ago. We have seen the Dallas Independent School District and Fort Worth Independent School Districts in Texas come forward and choose GHP’s as their preferred system for new schools as well as renovation projects,” Penn says.
Geothermal energy derives power from the earth’s heat. The energy comes from centuries-old radioactive decay of minerals, volcanic activity or from the sun’s heat absorbed on the earth’s surface. According to Penn, during hot summers, a GHP system cools the building by rejecting heat into the earth while in winter it takes heat from the earth and transfers it into the building.
Recently, Texas school districts that have added geothermal energy include the Irvine Unified School District, and the Burelson Independent School District. Irvine is developing the nation’s first net-zero middle school, while Burelson is opening a 550,000-square-foot high school this fall.
According to Penn, the K-12 school market in Texas is seeing energy savings of 30 to 50 percent using geothermal heat pumps. With their large property size, schools are a natural fit conducive to using geothermal energy sources.
However, support for geothermal systems has been growing, albeit slowly, despite successes. A case study of geothermal heat pumps in K-12 schools in Lincoln, Neb., conducted by the Oak Ridge National Laboratory (ORNL) in 2000, found that “based on actual metered energy usage data on average, the GHP new schools use 26 percent less source energy per square foot per year than the non-GHP new schools.”
According to Patrick Hughes, director of ORNL’s Building Technologies Research & Integration Center (BTRIC), “most schools that have chosen the geothermal heat pump system rationalize it on the basis of lower operating and maintenance costs throughout the life cycle.”
A recent success in using geothermal energy systems is Michigan’s Whitmore Lake High School, the state’s first LEED Silver-certified school. A study of the school’s geothermal system published by the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) Journal (May 2010) states that the combination of variable pumping and energy recovery ventilation with a hybrid GHP system “has helped to reduce energy costs by an estimated 35 percent compared to a conventional system.”
Meanwhile, in Texas, Cecil Cypert, director of Construction Services at Frisco Independent School District, has compared energy usage among schools using geothermal systems versus central plants in his school district. Cypert’s study presented at the Sustainable Innovation Summit in Dallas (June 2010), compared energy savings between schools that used geothermal systems and conventional central plants at Frisco in the 2008-09 school year. The study found that elementary schools using geothermal systems showed a 27 percent energy savings, middle schools had a 50 percent savings and high schools recorded a 58 percent energy savings compared to central plants.
However, geothermal energy is not for every type of school. “Typical rule of thumb is you need the same square footage of land for the well field as the square footage of space you are conditioning,” Penn says. For instance, at the Whitmore Lake High School, the geo-exchange field for this facility was located in 46 miles (74 km) of high-density polyethylene (HDPE) piping installed in a combination of horizontal loops and pond coils. Approximately 70 percent of the field is buried beneath the soil in a green area to the north of the school building.
Geothermal energy is not the answer for every type of facility, but is a cost-effective, efficient system for K-12 schools.
High Costs as a Barrier
According to Hughes, there is anecdotal evidence that in areas benefiting from well developed and competitive design and installation infrastructures, the first cost of GHP systems can be the same as conventional systems. “But if a school district’s local experts are telling them otherwise, who should they believe?” he asks.
Today, there is a significant installed base of GHP systems in K-12 schools, but there has been much less information sharing and best practices disseminated by different entities. Schools districts are slowly trying to move from the high cost barrier and are taking a longer term view. For instance, according to Penn, the costs for geothermal systems in Texas are similar to the cost of central HVAC plants.
“North Texas has seen a steady increase in the number of districts using geothermal in new construction. Some districts are even replacing older four-pipe systems with geothermal,” Mark Madorsky, P.E., president of the M.E.P. Division at PBK Engineering Division explains.
“On a national level, the market continues to demand buildings with lower overall energy consumption, and therefore smaller carbon footprints. Geothermal systems remain on the short-list of HVAC systems under consideration for projects with a high-performance or green mandate.”
Meanwhile, Hughes, who has pioneered the use of geothermal systems nationwide, is optimistic. “Fewer projects of any type may be happening right now, but given the attractiveness of lower life cycle costs, it is certainly possible that a higher percentage of them are using GHPs.”
The bottom-line for schools opting for geothermal systems is energy savings. According to Madorsky, “This comes in the form of lower electric bills at their GHP school sites. The reported energy savings is as much as 20 percent annually in reduced electric utility operating costs over similar facilities in their districts that utilize more conventional types of HVAC systems.”
In difficult times like these, raising money for schools to opt for geothermal systems is a challenge. “In normal times, schools interested in using GHPs usually obtain funding through conventional sources, such as bond funds. With the economic downturn, school revenues tied to local real estate values may be off and state budgets for education may also be in trouble, so raising money is more difficult,” Hughes says.
Students are using geothermal energy systems as learning labs despite the additional expense. The Irvine Unified School District in Texas is investing roughly $4 million in a geothermal system for their net-zero school, and they expect to recover it in 10 to 12 years. According to Penn “The school district will continue to save for years and put additional dollars to use for other programs.”
Despite its growth, the engineering community still remains skeptical about the use of geothermal systems in school districts and lacks expertise in this area. Many shy away from advocating the use of geothermal systems in the marketplace. Yet, with more school districts seeking geothermal systems, they are slowly shifting gears.
“The lack of experienced engineers with confidence and expertise in geothermal systems is the biggest hindrance today. If the engineering community would embrace the technology, the contractors and installer networks would grow to accommodate the market. A bad design equals bad installations equals bad results. The geothermal market must be fed and promoted by engineers to owners to overcome the stigma,” says Penn.
Hughes agrees that “growing more experienced design engineers and ground loop contractors is important if this market is to grow.”
School maintenance and facility personnel who have heard bad stories of geothermal systems failing in other schools are afraid of leaving the comfort zone. There is lot of unfamiliarity coupled with untrained maintenance personnel in this area. “Oftentimes, districts want to stick with what they know and don’t feel comfortable taking on the ‘learning curve’ of maintaining and operating a new mechanical system,” Madorsky says.
Experts agree that school districts are afraid of high first costs associated with using geothermal energy systems but the lack of knowledge regarding these systems is also serving as a hindrance. However, Madorsky states, “The market in Texas and nationally is becoming more aware of the potential viability of GHP’s which indicates a softening of the view that the GHP’s are too expensive. Most districts are willing to spend extra money up front for what they believe to be a sound financial investment, but many are still not willing (or able) to spend more.”
Other barriers include the lack of access to well developed and competitive design and installation infrastructures, and the lack of new technologies and techniques to improve GHP system cost and performance.
Role of the Private Sector
The private sector has played an important role in promoting geothermal systems in school districts. “There would not be a single system if not for the private sector,” Hughes says.
Equipment manufacturers, the few design engineers who understand and appreciate the system and the few dedicated ground loop contractors spend a lot of time and money educating school boards on the use of these systems. “Yet after several decades of best efforts by the private sector alone, many school districts have no local design and installation infrastructure and could not get a system implemented on their schedule even if they wanted to,” Hughes explains.
Design Changes Over the Years
Geothermal systems have seen design changes over the last several years. According to Hughes, "hybrid designs" are being used to help reduce the upfront loop field cost while retaining the system’s low operating cost over life cycle.
This is seen in the South, where the amount of heat to be moved from the building to the ground far exceeds the amount to be moved from ground to building on an annual basis. In a hybrid system, a fluid cooler is generally added to reject excess heat to ambient air, enabling the loop to be significantly reduced in size.
New designs also stress indoor air quality as it is a primary focus for school boards across the country.
“I have heard that one pipe distribution systems are being used and offer cost advantages in both new and retrofit situations,” he says.
Support From Utilities Is Mixed
The support from utilities to promote geothermal systems through financial incentives has been mixed. “Some offer rebates or electric rate reductions; however, the incentives are not as abundant as they were in the '80s and '90s. School systems are tax exempt so they cannot take advantage of the federal tax credits,” Hughes explains.
Madorsky states, “Utility companies are in a peripheral role as they seek to ‘partner’ with major energy users, such as schools, through incentivized rate structures that reward customers in the form of reduced energy demand charges. If a building has a lower overall electric load, then the peak demand charges to the building owner will be lower; GHP’s help reduce the overall load and thus lower the electric demand charges.”
According to Penn, his firm has been involved “with a national finance company to try to motivate districts by having the finance company serve as a ‘utility or lease’ of sorts, so the tax incentives can be passed through to the schools.” This involves either a leasing arrangement or a pre-purchased power scenario, Penn explains. “The financer must ‘own’ the system for five years to qualify for the tax incentives; therefore, a third party taxpaying entity is necessary to take advantage of the tax incentives.”
Schools choosing geothermal systems rationalize it on the basis of operating and maintenance cost reduction throughout the life cycle period and finance it through their conventional sources, such as bonds. In at least one area, bonding agencies are developing energy efficiency bonding situations, which use the energy savings to support the debt service.
“Financing systems can also play a role in GHP use. Performance contracting is a potential method of allowing a school district to ‘pay the note’ on borrowed funds used to install energy conservation measures, such as GHP’s. The more energy saved over the baseline, the larger the available buying power of the performance contract,” Madorsky says.
Sarat Pratapchandran is a writer specializing in education, environment and healthcare. His Website is www.lettersnatcher.com.