The earth’s crust is in pieces. Huge continental-size plates. The heat from inside the earth flows closest to the surface where these plates come together. Along the seams, the crust thins and fractures. Mountain ranges form. Volcanoes erupt.
A ring of 452 volcanoes defines the geography from the southern tip of the Americas, up and across the Bering Strait, all the way down to New Zealand. Mount St. Helens is just one volcano in this Ring of Fire along the periphery of the plates beneath the Pacific Ocean. Plate movements atop the earth’s mantle create tremendous energy. Oregon’s place on the Pacific Rim assures a resource of geothermal energy that can find its way to human use. Groundwater that flows into cracks and fissures of hot rock can carry the heat to the surface. A geothermal resource has three distinct applications: direct use of hot water, ground-source heat pumps for heating and cooling of buildings, and electric power generation.
The direct use of hot water has undeniable benefits for human health and well-being. Throughout the millennia, people have immersed themselves in hot springs. The minerals dissolved in the water at depth and carried to the surface have restorative properties. Belknap, Breitenbush, and Cougar are a few of the resorts people can enjoy in the Cascades. There are many more hot springs found just off the highway in Oregon. A geothermal resource near a town can provide hot water for heating buildings, greenhouses, and farming tropical fish. The indirect uses of geothermal heat are less obvious—the systems go underground. Beneath a building, the earth can act as a heat sink in summer and a heat source in winter.
Portland boasts the first commercial building in the United States to employ a ground-source heat pump. The Commonwealth Building began heating and cooling with geothermal energy in 1948. The heat pump is an exchange system with a looped pipe of fluid, usually water, that transfers heat between the air and the earth. At ten feet underground, temperatures reach an average of 50 degrees. This allows the warm air of summer to be exchanged with the cooler temperature underground and pumped to the building’s air conditioning system. And in winter, the earth heats the cold air. A heat pump brings the air down into the earth and through the building’s heating system to reach the desired temperature.
The occupants receive the benefits from a ground-source heat pump through reduced cost of operating the building, but the people that develop and build are often not the same group responsible for the long-term maintenance and operation. Developers usually want to sell or lease a building as quickly as possible. Since installing a heat pump increases the building’s upfront cost, the systems are often left out. Other factors contribute to this in Oregon, notably the temperate climate and an affordable power supply. Building codes and economic incentives from city and state governments can encourage a developer to consider the long-term benefits of ground-source heat pumps. The Oregon Residential Energy Tax Credit program provides an incentive for ground-source space or water heating systems. The most economic application of the systems is in schools, large commercial and government buildings, or district heating for residential areas. The Port of Portland headquarters uses 200 pipes for ground-source heating and cooling, with an auxiliary cooling tower for peak periods.
We Built This City on Hot Rock
Ground-source heat pumps do not require extremes of temperature and they have potential anywhere. But when it comes to renewables, generating power is hot. And Oregon has some hot rock under its more arid lands. The high temperatures needed for electric power generation exist in southern and eastern Oregon. The people of Klamath Falls have made direct use of geothermal heating in their homes since the early 1900s. In recent decades the City of Klamath Falls installed a downtown district heating system that provides direct heat for homes, schools, greenhouses, government and commercial buildings. The hot water is even piped under the sidewalks to melt snow. This town near the California border is home to the Oregon Institute of Technology (OIT). “At the OIT campus,” says John Lund, former director of the school’s Geo-Heat Center, “we put four million dollars in a deep well.” The school dug a 5,300 foot hole in the ground hoping to find steam, or at least some very, very hot water.
“The prediction based on geochemistry was 300 degrees, but all we got was something just a little under 200 degrees. Now we can still generate electricity,” Lund says, “because we can use a low-temperature power plant called a binary or Organic Rankine Cycle plant.” A geothermal resource below about 300 or 350 degrees Fahrenheit can generate power with a binary system using liquids that have a low boiling point. The hot water from the well is circulated through a heat exchanger that transfers heat to low-temperature fluids. The hydrocarbon fluids, isopentane and isobutene, are often used. These fluids readily turn to steam and power a turbine that generates electricity.
Knowing Where to Put a Hole in the Ground
The ability to detect geothermal reservoirs requires a combination of geology, technology, and intuition. Molten rock that once flowed to the surface can be buttery basalt rock spread over great distances, or it can be a more viscous rock called rhyolite. A geologist searching the desert floor and finding rhyolite, knows a volcanic flow originated nearby. The Oregon Institute of Technology used three-dimensional seismic mapping to determine where to drill. “Here’s our seismic profile along one line right through campus.” Lund points to a cross section representing data collected from a series of shock waves. “We had two lines, 1.35 miles each. Every 220 feet we put the dynamite—a small piece of dynamite. We start along one line, blow it and then measure everything.” Seismic mapping profiles the structure underground and can help locate fissures in the rock where water might flow.
“You set off surface shock waves that bounce off formations at depth,” Lund says. “You can do it with either dynamite or with these big thumper trucks.” Lund indicates a photo of a truck with retractable footings and an industrial-size sledge hammer that pounds straight down. “Even though we have these fractures,” Lund says, tracing his finger on the seismic map, “it doesn’t guarantee there is water. And of course, it doesn’t tell you anything about how hot the water might be. Electrical measurement will tell you the resistance to current flow through the ground. Less resistance signals more heat and water. If there’s colder water and less fluid, the resistance is greater.”
The final test and only confirmation of a geothermal reservoir is a very expensive hole in the ground. “The funding for exploration comes from private investment because the first phase, all the way up to drilling, is high risk. There’s a high percentage of failures,” Lund notes. “You’re trying to predict what the reservoir will produce. So it’s private investment and entrepreneurs. Not necessarily investors in oil and natural gas, just people willing to take a chance.” In much of the western region where they can find high temperatures, they have no water. That’s the problem, especially in the west. There’s not much extra groundwater. Without water, there’s no steam, and no power.
Transmitting Power: From Resource to the City
There is another problem: out in the middle of nowhere, there are no transmission lines. Lund points out, “There’s a lot of these resources in the boondocks and there is no grid or power line close by. For transmission, the plant tries to get a power purchase agreement to sell electricity to a company like Pacific Power. Then, they hook into their grid.” Now hopefully, their grid is close by. If not, the developer must pay to have a power line constructed from their plant to the tie-in, wherever that might be. In some cases, even if a power line is nearby, it may be at capacity. Lund initially thought they could tie into a major power line that runs from the Columbia River down to Southern California through Nevada. “Well, it’s already at capacity. So we’re going to have to either upgrade or run a parallel power line,” Lund says. “That’s one of the big headaches of developing wind, or whatever resource, is being able to hook into the grid.”
From exploration all the way to putting power on line, Lund estimates it takes five to seven years to develop a geothermal resource. The process requires getting permits to explore, to drill, and to build the power plant. And then the plant must get power purchase agreements to sell the electricity. After exploring and drilling proves a resource, Lund says that within a year or two the power plant could be on line.
“Each well you drill and each power plant you build is unique. There’s a certain amount of technology that can transfer, but the resources are each unique and you have to look at different ways of using them.” The particular temperature and chemistry of each geothermal resource requires the power plant to be designed to those conditions. Lund emphasizes that’s why it takes a year or two to build the power plant, because each situation is different. And the rock they’re drilling into can be peculiar.
Volcanic rock is difficult to drill because of the fractures and voids. The Ring of Fire is also known for its earthquakes. When you’re drilling for any resource deep in the earth, there’s always the risk of a minor earthquake. And complications arise with extreme temperature.
A blowout at Australia’s Cooper Basin on April 24, 2009 endangered workers, equipment, and infrastructure. They couldn’t contain the steam, and they couldn’t stop it with cold water. “It steams so much you can’t see what you’re doing,” Lund says, “and it scalds the workers.” The well explosion also sent down the value of geothermal stocks.
Getting Capital to Take a Risk on Steam
The companies that want to develop a geothermal resource will often finance the exploration themselves, because nobody else will. Even to build a small binary power plant, the company will need money to drill where there is no guarantee of a return. “No bank is going to invest in this stuff,” Lund says. “There are less risky things that they can make a return on. There’s a higher return on oil and gas because it comes on line a lot sooner, and there’s less up-front cost.” Oil and gas are usually in sedimentary rock. Whereas drilling for geothermal resources in volcanic rock and lava flows, because of the fractures and voids, is much more difficult. “There have been oil and gas drillers who have tried to drill geothermal wells, but they have not always been successful because there’s different chemistry involved, and temperature is usually involved.” Lund says, “There’s a different type of rock.”
A pool of bubbling mud at The Geysers, California led industrialists to drill a steam well there in 1960. California is now home to the world’s largest geothermal resource for electric power generation. The average depth of the steam wells is 8,000 feet. Drilling takes about 90 days and costs around five million dollars for each well. There are 350 steam wells and 100 miles of steel piping that run from the wells to 22 power plants. The Geysers reservoir north of San Francisco generates 850 megawatts, enough electricity for around a million homes, or all of San Francisco, Oakland, and San Jose combined.
“The Geysers is the largest geothermal field in the world in terms of power generation,” Lund says. “Very hot, very good resource, and it’s what we call dry steam.” If a plant manages the resource properly, it can continue indefinitely. A dry steam geothermal plant in Larderello, Italy has been in operation since 1911. The more common geothermal reservoirs are called “wet steam”. The wet steam reservoirs are hot water under pressure. When a power plant brings the hot water out of the ground, they reduce the pressure and it flashes to steam. During the late 90s, extraction at The Geysers began to deplete the steam field. Fortunately, the field can be recharged by pumping treated sewage effluent to the plant from nearby water treatment facilities. “It’s slowly coming back now,” Lund says of The Geysers. “One company owns almost all of the plants now. So they are managing it a lot better.”
The companies are there to make money, and if they manage the resource they can make their money long-term. Private enterprises generally own the geothermal energy, unless it’s on public land. If it’s on public land, they have to pay a royalty to the federal government to use the resource. Lund says, “State or federal government has financed some of the drilling in the past.”
Oregon State Senator Ron Wyden and U.S. Representative Greg Walden have been supportive. “They are very into geothermal and have gotten us a number of grants for the Geo-Heat Center,” Lund says. Walden represents the Second Congressional District that includes all of Oregon east of the Cascades. The Department of Energy (DOE) supported the purchase of a 280 kilowatt binary system for the Geo-Heat Center. The unit began producing power in 2010 and laid the groundwork for an additional $3.5 million from the DOE, with a matching investment from the university.
The geothermal resource on campus provided an opportunity to demonstrate innovative technology able to generate electricity from low-temperature resources. Compared to conventional binary systems, the OIT system runs at an estimated 20 percent cost savings. The project received additional support of a million dollars through the American Recovery and Reinvestment Act, and industrial partner Johnson Controls Inc. provided $4 million to help demonstrate the new technology in Klamath Falls. With proven geothermal power generation at The Geysers in California, Larderello in Italy, Matsukawa in Japan, and Kamojang in Indonesia, maybe Oregon could one day be among the world’s top producers of geothermal energy. The first geothermal plant in Oregon to produce industrial scale electric power opened November 2012 at Neal Hot Springs, just west of the town of Vale in Malheur County. And near the City of Klamath Falls, two wells have been drilled in the Olene and Poe Valley by Klamath Basin Geopower. Launched in 2009, the company has plans for the building and commissioning of a power facility by 2017.
New technology to tap resources has generated more interest in geothermal energy. Enhanced geothermal systems (EGS) allow reservoirs to produce energy in areas that have hot rock, but no permeability or water. Lund says, “In theory, you can do it anywhere in the country, but you do need the water to bring the energy up to the surface.”
Newberry Volcano in Central Oregon about 20 miles south of Bend, with two alpine lakes nearby, is a hot spot for developing enhanced geothermal. The Newberry EGS Demonstration received a matching grant of $21.5 million from the DOE (Google contributed $6.3 million) and next steps include planning, permitting and drilling of a production well. The ballpark estimate for the amount of power to be generated from the first pad at Newberry is between 30 to 50 megawatts, enough to power a city the size of Bend. Additional benefits include revenue from the royalty stream with money going to Deschutes County and to the state. The project will employ people over several years during the construction phase, and then around 20 people will run each plant, totaling about 100 full time jobs—with the secondary economic benefits felt throughout the area.
Whether a power plant is nuclear, coal, or gas, it’s creating superheated steam to power a turbine. By doing a bit of digging, it’s possible to tap superheated steam at the source. The earth’s heat is an inexhaustible resource of geothermal energy. Given the increasing economic and environmental cost of burning fossil fuels, geothermal is a good opportunity to reduce carbon emissions and connect Oregon to a renewable resource for the long term.
Residential Energy Tax Credit for Ground-Source Heat Pumps
The Geo-Heat Center at Oregon Institute of Technology http://geoheat.oit.edu/
Interactive Geothermal Map of Oregon http://www.oregongeology.org/gtilo/
Geothermal in Oregon: Where it is being used, Where it can be used http://www.oregon.gov/ENERGY/RENEW/docs/tp124.pdf
Proceedings World Geothermal Congress 2005, United States of America Country Update http://www.osti.gov/geothermal/servlets/purl/895237-Vp8ett/895237.pdf
Klamath Basin Power http://kbgeopower.com/
U.S. Geothermal Inc. http://www.usgeothermal.com/projects/2/Neal%20Hot%20Springs
Newberry Geothermal Project Video https://www.youtube.com/watch?v=j9UBzFA4clg
Newberry EGS Demonstration Blog http://blog.newberrygeothermal.com/
Alta Rock Energy http://altarockenergy.com/projects/newberry-egs-demonstration/