Geothermal powers resort
New UTC plant uses low-temp water, saves small fortune by replacing diesel
By Sarah Hurst
For Petroleum News
Battling sub-zero temperatures is always a challenge for energy projects in Alaska, but now it’s also possible to tap into the natural heat source that lies beneath the ground and use it to produce electricity. Bernie Karl, the owner of Chena Hot Springs Resort, charmed and cajoled his way into winning Alaska’s first geothermal power plant, which was officially unveiled in the presence of U.S. Sen. Ted Stevens, Gov. Frank Murkowski and an army marching band Aug. 20.
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The truck-sized plant, nicknamed the Chena Chiller, had already been running for almost two weeks before the celebratory event was held. “It’s purring like a kitten in a creamery,” Karl boasted to his guests. To be more precise it was emitting a continuous high-pitched whine, due to the turbine blade spinning at 15,000 rpm. Next to the power plant stood a few of the old steam engines Karl collects. “I want to show mean and steam versus lean and clean,” he explained.
UTC testing power plantKarl acquired the geothermal power plant for his resort, 60 miles northeast of Fairbanks, by working with Connecticut-based UTC Power and government agencies. UTC wants to test its plants at various locations around the country before marketing them commercially. Chena is particularly unusual because the plant here has been adapted to run on water that comes out of the ground at a temperature of 165 degrees Fahrenheit. This is the lowest-temperature water being used in a geothermal plant anywhere in the world, according to UTC.
The concept of the power plant is relatively simple: it’s refrigeration in reverse. The design of the plant is very similar to that of a centrifugal water chiller, used for air conditioning systems. The hot water in the geothermal plant vaporizes a fluid called R134a, a standard refrigerant, which has a lower boiling point than water. The vapor builds up pressure to drive the turbine and generate power. Then the water is cooled down and reinjected into the ground so that it can eventually be used again. This is technically known as an organic rankine cycle. It is fuel-free and emission-free.
“We have taken the Henry Ford approach to this organic rankine cycle solution,” UTC’s Halley Dickie said in a presentation at Chena. In other words, UTC is adapting a geothermal power plant that is typically customized for each client and manufacturing it with off-the-shelf components so that it will be affordable. UTC expects to sell a plant for about $1 million and it will pay for itself in savings in one year. Bernie Karl received government grants to help pay for his plant.
Chena Chiller produces 200 kWRunning at full capacity, 500 gallons of hot water and 1,500 gallons of cold water will go into the Chena Chiller every minute, to produce 200 kW of electricity. At a power cost of 5 to 7 cents per kilowatt-hour, compared with 30 cents for the diesel fuel generators that Karl previously used, it will save him about $1,000 a day. “Bernie’s made a money machine,” Dickie said.
At Chena the geothermal resources were obvious because of the hot springs. Still, it takes a drill program and extensive testing to determine the size of any underground geothermal reservoir. Arctic Drilling has been working at Chena and plans to bring in a big rig that can go down 6,000 feet. “At 1,010 feet we were at 179-and-a-half degrees and if the drill hadn’t broken off we’d still be drilling,” Karl said. The hot water currently powering the turbine comes from a depth of 700 feet.
Geophysicist David Blackwell from Southern Methodist University in Dallas recently added a chemical tracer to the well that should help to find out how long it takes for the water to come back through the system for a second cycle. The longer it takes, the larger the reservoir. A surface manifestation of geothermal energy such as a hot springs isn’t essential in the search for a resource. “You can find geothermal anywhere if you get deep enough,” Blackwell said. “Geothermal systems are kind of like mineral deposits — they’re really random.”
In the 1970s and ‘80s most geothermal exploration in the United States was done by oil companies, but the limitations of power plant technology at the time made projects uneconomic, and much less was known about how to deal with volcano hazards. Today many of the world’s geothermal power plants are built on volcanoes and scientists know where to place them so that they are not at risk. Oil companies also lost the incentive to explore for geothermal resources when petroleum was cheap and plentiful for consumers. Now that oil and gas prices are high, geothermal is back in business.
Geothermal operates at full capacityGeothermal energy has some huge advantages over wind power and solar power, too. A geothermal power plant operates at full capacity most of the time. Wind power can only be used about 25 percent of the time and solar power has only a 14-percent utilization rate. In Alaska, power is needed most in the winter, when there is no potential for solar power. Geothermal energy can also be used directly, rather than converting it to electricity.
The buildings at Chena Hot Springs Resort have already been heated by water from the ground for several years. The geothermal reservoir is constantly replenished by precipitation, of which there is no shortage in Alaska.
UTC Power is part of the United Technologies group of companies which include Hamilton Sundstrand, Otis, Pratt & Whitney and helicopter manufacturer Sikorsky. Jean Copin of the United Technologies Research Center compared Bernie Karl’s adventurous spirit to that of Elisha Otis, who got in an elevator and ordered the rope suspending it to be cut to demonstrate the effectiveness of his safety brake.
Goal to sell power to Golden ValleyUTC plans to install its first 1-MW geothermal power plant at Chena when it is developed. Karl, who always thinks big, would like to produce 20 MW eventually and sell power to Golden Valley Electric Association. Karl told guests that he invests regularly in UTC because he has such faith in their products, “and I’m as tight as a frog’s ass,” he added, causing riotous laughter.
“We have had a real problem in the past to get such partnerships going” for alternative energy projects, Sen. Stevens said. “We have not had a leader such as Bernie. ... It is for us to demonstrate to the rest of the country that we don’t have to do it all with federal money.” Gov. Murkowski was also full of praise for the self-described “imposter” with no formal education who had upstaged the assembled politicians and scientists. “Most people didn’t believe you could take hot water and make a generator out of it, they didn’t believe there was enough heat. You’ve proved them wrong,” he told Karl.
Chena Hot Springs Resort is a showcase for innovation, with greenhouses full of tomatoes and lettuces grown hydroponically (in liquid nutrients rather than soil), providing a testing ground for several agricultural projects run by the University of Alaska Fairbanks. The marching band from Fort Wainwright led visitors past a goat pen and an organic vegetable garden on the way to the power plant.
A former ice hotel full of elaborate sculptures, with a working Martini bar where drinks are served in hand-carved ice glasses for $15 each is kept cold throughout the summer — geothermally, of course. It now serves as a museum because it didn’t meet the regulations for a hotel, lacking certain features like wheelchair ramps and toilets. The original ice hotel melted after the first winter. “Forbes voted it the worst business idea for 2004,” said Karl. “So I rebuilt it.”
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Geothermal resources widespread in Alaska
Three major regions hosting geothermal resources are known in Alaska: the Aleutian volcanic arc, Southeast Alaska and Central Alaska, which stretches from well-known hot springs such as Chena, Manley and Circle in the Interior west to Pilgrim and Serpentine hot springs on the Seward Peninsula. Of these the Aleutian arc probably contains the greatest resources. A fourth resource is located near Mount Wrangell in Southcentral Alaska. The resources in Southeast and Central Alaska are probably fault-hosted rather than volcano-hosted.
The Aleutian arc encompasses the Aleutian islands themselves as well as the Alaska Peninsula and the volcanoes in Cook Inlet. Fumaroles — openings in the earth’s crust that emit steam and gas — near Akutan volcano on Akutan Island, as well as another location near Makushin volcano on Unalaska Island are hot prospects, according to Amanda Kolker, a geology Ph.D. student at the University of Alaska Fairbanks who is researching geothermal energy. Both areas are close to communities that could use the power, the villages of Akutan and Dutch Harbor.
Also part of the Aleutian arc, Mount Spurr and Crater Peak just 80 miles from Anchorage have seen very limited geothermal exploration, but there is probably a system at a depth of 1,000 meters, Kolker said in a presentation at Chena. Mount Wrangell, which hosts a separate geothermal system, is more silicic and less explosive than the Aleutian volcanoes, Kolker added.
More than 30 hot springs have been identified in the central Alaska region, but their heat source is not known. They are all geologically similar, located near a high-potassium pluton that is between 60 and 90 million years old. A pluton is an intrusive igneous rock body that crystallized from a magma below the surface of the Earth. The hot water at Chena comes up from within an enclosing pluton of granite.
Southeast Alaska is probably the least-explored region, containing 14 known hot springs, most in remote areas. Their chemistry and temperature estimates are very variable, and are at at depths of between three and five kilometers. “The geothermal applications in Alaska are limitless,” Kolker said. “We need heat here and we’ve got a lot of it underground.” The Alaska Energy Authority published a renewable energy atlas of Alaska in August.
California, the world’s fifth-largest economy, is one of the nation’s leaders in the use of geothermal energy, with nine geothermal power plants providing 6 percent of the state’s electricity. Nevada has 10 geothermal power plants, Idaho has three, Utah has two and Hawaii has one. Most of the geothermal resources in the United States are in the western states. One potential obstacle to developing the resources is that many of them are in state and national parks. Nevertheless, it is estimated that there is enough geothermal energy within three kilometers of the earth’s surface to provide a 30,000-year energy supply for the United States at current usage rates.