Geothermal as a clean energy solution

While it’s true the buildout of this clean economy needs to speed up, the fact is, there are still new technologies and strategies waiting to be tapped that offer hope for the future. One of these is power generated by next-generation geothermal techniques. Simply put, this technology uses the heat of the Earth’s super-hot interior, rather than coal or natural gas, to drive steam or plasma to spin the turbines that generate electricity.

This inner-planetary heat is free, non-polluting, and endlessly renewable. All we need to do is keep developing the technology so we can put it into use. Once we do, that power will be available 24 hours a day, every day of the year. That’s a big leg up on wind and solar, which have down times.

So how exactly does it work? You may be familiar with conventional geothermal applications that draw from heat sources relatively near to the Earth’s surface. Individual homes or collections of buildings can use the stable temperature just below ground to heat buildings just as a traditional heat pump would.

Geothermal power plants go a bit deeper to tap into reservoirs of heated water underground. This hot water or steam is brought up to power the generator, then cooled water is pumped back down into the reservoir where it can be reheated. Geothermal power plants in the United States currently can produce almost four gigawatts (GW) of electricity, enough to power about three million homes.

The fact that existing plants need an accessible underground hot water source limits where they can be located—largely in the Western United States. Luckily, advanced drilling techniques have enabled developers to bore through solid rock layers to get to deeper sources of ever-greater heat miles below the surface. Since the Earth gets hotter the further down you go, there is exponentially more heat available, unlocking the ability to create vast amounts of electricity. This means plants would no longer be limited to where there are near-surface reservoirs, meaning they could be deployed in greater numbers across the country.

Efficient and scalable clean energy

The U.S. Department of Energy’s recent Liftoff Report estimates that advanced geothermal technologies could power 67 million homes by 2050, or in a highly aggressive scenario, as much as 225 million homes—almost the entire country! That would be a major contribution to the reliable, clean power we need to avoid the worst effects of climate change.

What’s more, geothermal resources can produce all this using a fraction of the land needed for large wind and solar installations. These plants just require a well to bring up the heated liquid and steam, a facility to generate the electricity, and a well to pump the liquid back down.

This is much less intrusive on the landscape than hundreds—or even thousands—of acres for other renewables, with far less conflict for wildlife and other resources. Locating them on already disturbed sites such as decommissioned fossil plants or oil and gas drilling wells and along existing transmission routes will further reduce their impact.

Finally, these facilities provide a direct career transition opportunity for workers in the oil and gas industry. The well-drilling techniques—but not the pollution—are taken right from that industry, and the power plants operate the same as fossil plants, just with a different heat source. No re-training is necessary, nor should there be a wage disparity for former fossil fuel workers. The startup companies pioneering this space claim 75 percent or more of their workforce has come directly from the fossil fuel sector.

What is needed?

There are a few companies advancing next-generation geothermal technology and proving it can be done at a large scale. But, whereas wind and solar have had decades or longer to invest, build, and achieve commercial viability, new geothermal applications are starting from scratch. They need basic research to show they work reliably across a variety of locations. This is what brings confidence from investors to finance what is, admittedly, a high initial cost. After that will come economies of scale, as more plants are built and costs come down.

The Liftoff Report estimates the government and private sources will need to invest $20-$25 billion between now and 2030 to help get the industry on solid ground. As much as $250 billion more will be needed over the next 20 years to achieve the industry’s promise. That’s a lot of money. But it’s on par with the investments that have been made in the last few decades for wind and solar, and far less than the cost to society of the oil and gas industry.

Looking at all the potential, it seems well worth and well past time to give next-generation geothermal the attention it deserves.

The first speaker, Lowell Rasmussen of University of Minnesota Morris, gave examples based on UMM’s pioneering biomass installation and their current and future wind turbines. He pointed out that despite the fact that many people are afraid of making the big changes required for moving to renewable energy, maintaining the status quo may in fact be the “riskier” path. Traditional energy practices are dependent on outside sources, which means that both procurement and prices are outside a college or university’s control. On-site generation is not only able to save a college money in the long run at current rates, but also protects the campus from unknown complications that may arise in the future as traditional energy sources (such as coal) become more hotly contested. Among the ideas he favors for financing renewable installations are: internal loan pools, conservation ESCOs, power purchasing agreements, soliciting external investors. He advised college representatives or business officers to reference NACUBO‘s book Financing Sustainability on Campuses.

Up next was Cindy Shea, from America’s oldest public university: University of North Carolina, Chapel Hill. UNC is in a unique position when it comes to energy, because they have buildings that range in age from over 200 years old to brand new.  As a state school, all of the new buildings must adhere to recently-implemented North Carolina regulations requiring they be 30% more efficient than ASHRAE standards. They began their move towards renewable energy in 2003 with a student-led initiative to start a Green Energy Fee, which raises $200k per year. These funds, which are controlled by the student-led Renewable Energy Special Projects Committee, are then leveraged to secure additional grant monies and state funding.

Like UMM, UNC has chosen to invest in on-campus projects rather than offsets or buying “green” power from external vendors. These projects include a solar thermal system on one of the residence halls, geothermal wells, photovoltaic arrays on new parking deck, bio-diesel fuel for on-campus shuttles, and a large-scale energy-efficiency campaign begun in 2009 to retrofit buildings and also promote environmentally conscious behavioral modifications. For these low-cost measures, the investment of $150 in energy management staff and media yielded a savings of $4 million dollars annually. Shea advocates starting with what is cheap and easy to do, and investing the savings that result in more expensive projects.

The final speaker, William Leahy of Eastern Connecticut State University, made the point that when embarking on a large-scale endeavor, a college or university rarely uses only one kind of financing. The recent economic downturns further complicate this delicate balancing act. Although many schools have signed on with the ACUPCC,  he said, the question is how to find the right variety of sources in the right combination to  fund the needed investments in energy efficiency and renewable energy to meet the 2050 carbon neutrality.Leahy listed several broad categories of funding sources that each campus can and should draw from to find that perfect balance: internal sources such as endowment funds and alumni gifts, student fees, revolving loan funds, grants, rebates & incentives, bonds, leases, performance contracting and renewable energy credits. While the dollar amount of each receipt may be seem small in comparison  to the total cost of a renewable insteallation, by using some or even all of these sources in coordination, a college or university will be able to achieve a lot more than if they focus solely on one individual funding source.

This amendment, sponsored by Senator Wyden (D-Ore.) would authorize $500 million ($100 million per year for five years) to ensure that workers are ready to create, install and maintain wind, solar, biomass and geothermal projects. Once passed, the bill authorizes the Department of Energy to fund programs at 1,200 American community colleges, with half of the funds going towards schools who already have strong programs in place. 

A letter sent on Monday by National Wildlife Federation to Senators Bingaman and Murkowski, Chairman and Ranking Member of the Senate Committee on Energy and Natural Resources, supported the inclusion of provisions for community colleges and stated, "This amendment would establish a community college-based training and education program for sustainable and alternative energy technologies such as wind energy technicians, energy auditors, geothermal energy technicians, and energy efficient construction."

Organizations such as NWF and the American Association of Community Colleges also point out that this amended bill supports education and training for workers in sustainable agriculture and farming. Recent articles in ClimateEdu and the Chronicle of Higher Education have explored the issue of teaching sustainable agriculture, but focused on liberal arts schools like Warren Wilson College and the University of Montana. Community colleges have largely stayed out of the farming arena (Central Carolina Community College being one of a few notable exceptions), but may soon be able to take advantage of federal funds for such projects.

However, such a day is still far off. The New York Times reports that the bill is still in early drafting stages, and due to the inclusion of mandatory limits on carbon emissions through a cap-and-trade market, lacks Republican support.

In many regions, early reports suggest there are not enough workers to meet demand for wind, solar and geothermal projects, while some states find the opposite: that there are more trained professionals than there are jobs. A report from the National Council on Workforce Education states,

“[M]any jobs that are currently, or predicted to be, in demand are ‘middle-skilled’ jobs that require more than a high school diploma but less than a bachelor’s degree. It is important to note that although there will be a growing number of new green occupations requiring new knowledge, skills, and abilities, it is expected that the majority will be transformed from existing jobs, requiring a redefinition of skill sets, methods, and occupational profiles.”

To more accurately predict when and where workers will be required, not to mention training these workers, she reports that community colleges are turning to local organizations and pioneering a new collaborative model that can “respond to trends in clean and green technology.” One such project, the New Energy Workforce (NEW) Initiative, a partnership between Bay Area community colleges and regional workforce investment boards, is able to conduct courses, research employment opportunities, and share successful curricula between schools.

Kitty O’Doherty, convener of the NEW project, says, “This is a call for new levels of collaboration. We convened the Workforce Investment Boards and the colleges in our region in February, and both groups are extremely committed. They [WIBs] are going to have the funding to place people in these jobs, and we’re going to have the training. The common mission of preparing individuals for meaningful careers and creating a well-qualified workforce for our region is a very compelling motivator.”

What's most interesting is how the project will be funded:  The university already had $40 million from the state legislature to replace aging and inefficient boilers, but received no bids for the project, even as the cost of the upgrade rose to $60 million. Now, BSU will ask the state budget committee to re-apportion the money to the ground-source heating project.

The project could eliminate the 85,000 tons of carbon dioxide emitted by the current boilers. It also has the potential to decrease university operating
costs, reduce dependence on coal and natural gas market fluctuations,
eliminate other air pollutants, and allow the university to
sell carbon credits. BSU also hopes it will create about 870 jobs, though not all will be permanent.

We talk a lot about geothermal, because the paybacks for a properly installed ground-source heating system are bigger than most conservation measures and even some renewable energy sources. The majority of energy consumption on campus buildings goes towards heating and cooling. Richard Stockton college, using a closed-loop system similar to the one that Ball State proposes, cut its electricity consumption by 25% and its natural gas uage by 70%, saving approxiamtely $330,000 in energy costs per year after an initial investment of only $5 million. BSU's plan is much more ambitious, and could lead to the biggest ground-source heating installation yet in the United States.

In short, geothermal electricity comes from using scalding groundwater to power turbines and generate electricity, and ground-source heat pumps use the temperature of the earth to heat buildings in the winter and cool them in the summer (although electricity from another source is necessary to power these pumps, they are often more efficient than traditional HVAC systems).

Location really determines the potential for using these technologies. Oregon Institute of Technology, geologically-blessed as it is, has identified enough geothermal energy to power its entire campus off superhot groundwater, and is already in the process of doing so. Other colleges, lacking that resource, are experimenting with ground-source heat-pumps, both open- and closed-loop.

We covered both types last fall, with a three-part series on geothermal and ground-source heat. The first piece describes electricity-generating geothermal installations (like the one at OIT), the second explains ground-source heating/cooling, and the final story
breaks down some of the most interesting campus examples of
ground-source heating, with figures on cost, energy savings, and
drawbacks. 

As we were researching these stories, we found that these systems
are not only complicated, but also very sensitive to the geology of
their region, making a universal, fool-proof process, particularly for ground-source heating, hard to implement.

Bill
Johnson notes in an article for Facilities Manager that “the state-of-practice shows high geothermal system failure rates, particularly in large-scale applications. This is especially true for open or standing column well designs, which require specialized geologic and hydrogeologic expertise.”

Since a university definitely qualifies as a “large-scale application,” what can be done to reduce the failure rate? These installations are hardly cheap.

Johnson recommends a phased approach, in which geothermal engineering experts are brought in for preliminary studies where information on everything from the site footprint, HVAC loads and GHG emissions targets to hydrogeologic data and permitting issues is collected. Then, after the installation of a test well and detailed reports of the well field, construction can move forward, monitored all the while by trained geotechnical engineering experts. Everything from soil structure to aquifer sustainability must be taken into account to ensure the wells continue to function.

When applied correctly, Johnson says, these systems are invaluable. “Proper application of ground source geothermal technology can dramatically impact the efficiency and financial performance of energy utilization (30%+) in a building or on a campus. At the same time, this alternative energy resource can significantly contribute to the institution’s carbon reduction goals. Geothermal applications also offer the possibility of aesthetic and noise abatement benefits (eliminating cooling towers and dry coolers in sensitive locations or on historic structures) and, when combined with “green” or lower cost, on-site electrical power, the benefits are many.”

Beijing’s Bird’s Nest stadium was the focal point of the 2008 Summer Olympics due to its stunning architecture, but the structure was also a demonstration site for a gold-medal renewable energy technology little-known by the public: ground-source heat pumps.

Water pipes buried deep beneath the stadium’s infield provided heating and cooling for the athletes’ locker rooms. “The loop-field is right under the grass where the guys were throwing the javelin,” says engineer Phil Schoen, who consulted with Chinese officials on the design of the ground-source heating system.

Ground-source heat pumps, also called geothermal heat pumps, can shave heating and cooling bills by 50 percent, making them an attractive alternative to traditional furnaces and air conditioners. They tap into the relatively constant temperature just below the earth’s surface. In winter, the systems transport warm water into buildings where the heat is extracted. In summer, the process is reversed: Water pulls heat from inside buildings and dumps it underground.

“We’re just heat movers,” says Jim Bose, executive director of the International Ground Source Heat Pump Association and an engineering professor at Oklahoma State University.

More than a million geothermal heat pumps have been installed in homes and buildings nationwide. The Oklahoma State Capitol is heated and cooled with this technology, as is President Bush’s Crawford, Texas, ranch. Al Gore had a system installed on his Tennessee mansion after the release of the movie “An Inconvenient Truth.” Combined, these systems reduce the nation’s annual fossil fuel use by the equivalent of 21.5 million barrels of oil and cut carbon emissions by 5.8 million metric tons-equal to removing 1.3 million cars from the road, according to industry statistics.

Now, after years of obscurity, ground-source heating and cooling is poised for a rapid expansion. “There is a perfect storm right now with rising energy bills, concerns about energy security and climate change,” says Dan Ellis, president of ClimateMaster, the nation’s largest manufacturer of geothermal heat pumps. The company’s sales have tripled in the last five years.

“We’re growing by leaps and bounds,” says Jack DiEnna, executive director of the Geothermal National and International Initiative. The trade group is pushing the technology worldwide and hopes the industry can capture 30 percent of the market for heating and cooling by 2030. Interest is booming in China, England, Japan, South Korea and Australia, among other nations, DiEnna says.

Domestically, interest is booming thanks to a homeowner tax credit in the federal economic bailout bill approved by Congress in October. The $2,000 Residential Renewable Energy Tax Credit is “a historic milestone” for ground-source heating, says John Kelly, executive director of the Geothermal Heat Pump Consortium. Geothermal heat pumping has lagged behind wind and solar energy in federal support. “Now we’re on a more level playing field,” Kelly says.

All of this is none too soon for Bose, who is sometimes called the “father of ground-source heat pumps in the United States.” He remembers the excitement of first learning about these devices. It was 1974, and the young Oklahoma State professor found an article about the technology in the library. “I was fascinated,” Bose says. “I kept reading and reading and looked up everything I could find out. I thought: ‘Why isn’t this being used?'”

The first ground-source heat pump in North America is believed to have been installed in the 1940s in the home of an employee at Indianapolis Power and Light Company. The technology got a boost during the 1970s energy crisis but federal aid was eliminated in the 1980s and interest languished through the 1990s due to low energy costs. The technology also suffered from a public relations problem: Wind and solar have visible infrastructure (photovoltaic panels and turbines), but most of the hardware on a geothermal heat pump system is buried.

Geothermal heating and cooling should not be confused with geothermal electricity, which taps hot water thousands of feet underground to power electric turbines. (For more on this, see our previous article “The Heat Beneath Our Feet,” about geothermal energy.)

The two main elements of a geothermal heating and cooling system are the heat pumps, located indoors, and the loop field, where the water-filled pipes are buried. Loop fields are either open or closed. Closed-loop systems are completely sealed, and the water inside the pipes often contains a relatively safe anti-freeze such as ethanol. Open-loop systems draw water up from an aquifer, extract the heat and return the water to the aquifer. Large systems typically use vertical loops whose polyethylene pipes can reach down 500 feet or more. Smaller residential systems often have horizontal loop fields buried just six feet underground.

Water circulates through the loop field and is pumped into a home or building, where one or more heat pumps extract and concentrate the heat, which is then circulated through ductwork as in any central heating or cooling system. In summer, heat pumps reverse this process. They extract heat from indoor air and transfer it to the water, which dumps the heat underground. Some systems also provide hot water for showers and sinks.

The technology is fairly simple. In fact, most homes already have heat pumps–refrigerators and air conditioners. Both of these pump heat from one place (inside the refrigerator or home) and move it to another (outside). These air-to-air heat pumps are less efficient than air-to-water geothermal systems, however, because water is a superior medium for heat transfer. The principal drawback to geothermal heat pumps is the up-front cost. Drilling the loop field and installing the underground pipes can add two-thirds to the cost of installing a traditional HVAC (heating, ventilation and air conditioning) system.

However, geothermal systems can pay for themselves in several years due to lower heating and cooling bills. Tax credits and other government incentives can shave the costs even more. New York’s Hamilton College added a geothermal system to its historic Skenandoa House residence hall in 2003. The 21,000-square-foot building now uses 40 percent less energy than a similar hall on campus. “This is the most efficient building we have in terms of energy use,” says Steve Bellona, associate vice president for facilities and planning. Thanks to a state rebate, the system cost the college just $32,000–paying for itself in less than three years.

“The challenge is to get more colleges and universities to understand the value of this,” says Lynn Stiles, a physics professor at New Jersey’s Richard Stockton College, which installed a system in 1994. “This was a wise investment for us.” The system has cut electricity use about 25 percent, natural gas use by 70 percent and saved the school more than $300,000 per year in energy costs. It cost $5.8 million to install, though the school would have paid $4.2 million to install a traditional HVAC system, so the additional cost was just $1.6 million-much of which was covered by state and utility grants.

Stiles says geothermal heat pump systems have low maintenance costs once they are built. The high-density polyethylene pipe used in loop fields is made to flex and resist breaking. This is the same material often used in natural gas pipelines. “You rarely hear about problems,” Stiles says. The loop fields are typically built to last 50 years. That is comparable to the life-span of any well-built heating and cooling system. The heat pumps themselves are located indoors and have similar maintenance costs as any space-heating or cooling device.

While the amount of electricity used to run the pumps is different for every building, some studies indicate ground-source heat pumping is most economical in areas with high natural gas prices. A study conducted by the Department of Energy on four schools in Kansas with geothermal heat pumps found this technology to be the most efficient choice with the lowest life-cycle cost for heating and cooling the schools. A 1993 Environmental Protection Agency study likewise found ground-source heating and cooling to be the most environmentally sound, efficient and cost-effective space-conditioning system available. Even so, more study is needed to pinpoint their overall efficiency. Federal funding for research has been limited over the past decade.

But ground-source heat pumps are no panacea. The pumps and ventilation systems require electricity to run. This is why some projects include photovoltaic panels, though this adds to the cost. Proper design is also crucial: Large installations must be carefully engineered so they do not heat up the ground or groundwater, harming micro-biota and diminishing the ability of the soil to absorb heat over time. “You want to maintain thermal balance,” Stiles says. Closed-loop systems also occasionally leak.

“Geothermal heat pumping only achieves the best efficiency if you design the building appropriately,” says Tony Grahame, director of residential building technology at Arizona’s Yavapai College, whose AgriBusiness and Science Center has a geothermal system with a closed-loop field consisting of 32 vertical wells drilled 300 feet deep to access an underground aquifer. “If you didn’t design the building efficiently then you don’t get the savings you could.” Grahame says he is unaware of the energy savings because the building’s energy use is lumped in with other campus buildings. “It’s hard to separate out the savings because they didn’t put in separate monitoring systems.”

Geothermal heat pumps are one piece of the energy puzzle, advocates say. Buildings and homes use 40 percent of the nation’s energy. Using heat in the ground dramatically reduces the need for fossil fuels. “The dynamics have never been better for our industry,” says Schoen, who consulted on the Bird’s Nest. His company, Geo-Enterprises, is growing about 20 percent per year.

For college students facing a tough economy, tapping the low-grade heat below promises good job growth. “We need young engineers to be taught this technology,” DiEnna says. “Engineers are the key.”