One great thing about true EcoGeeks is that while their opponents are wasting time trying futilely to disprove the problem, they're hard at work dreaming up solutions. A perfect example of this is the Chena hot springs resort located to the northeast of Fairbanks in Alaska. Its engineers and entrepreneurs have cooked up not one but a bevy of eco-friendly technologies that make sense from a financial, environmental, and social perspective.
At the core of their efforts is a low-temp hydrothermal reservoir, which contains 165 F water. This is “low temp” as in the past it was thought that only 300 F reservoirs or higher would be effective for producing power. However, lead engineer Gwen Holdmann and her team devised an innovative power generator, which uses vaporization of refrigerant to drive a turbine, instead of water vapor steam. The refrigerant is then condensed using the naturally cold ground water, located away from the hydrothermal source.
The plant cost a mere $2.2 million to build as it uses all off the shelf parts. It produces 200 kw at a cost of 5 cents per kwh, compared to the former costs of 30 cents per kwh when using diesel. The design is projected to pay for itself within four to five years. Hydrothermal power is very promising, as it is estimated that the water beneath the Earth’s surface holds 50,000 times the amount of energy in the remaining gas and coal resources. Additionally, the Chena team has a grant to build a similar design to take advantage of waste water from oil production, which is at a similar temperature. Experts estimate that oil waste water employed this way could produce 6,000 to 11,000 megawatts of electricity. This would both reduce energy costs and prolong the lifespan of dwindling fossil fuel resources.
Not to be forgotten is Chena’s unique refrigeration system, which uses a three-pressure system and ammonia-water cycles to chill brine to minus 20 F. Such a system saves Chena $188 a day and limits the use of toxic refrigerants. Lastly, the town of Chena is literally going green; it has used the hydrothermal resource to devise a unique hydrothermal heating for both the buildings of the city, and a special 4,300 square foot greenhouse. The greenhouse allows delicious produce to be grown year round at virtually no cost.
Bernie Karl, Chena’s owner, isn’t done yet. He’s putting Holdmann to work on a project to generate hydrogen using part of the hydrothermal electricity. This hydrogen, mixed with propane, will fuel Chena’s vehicles. The idea of using a hydrogen propane mix is considered very doable from a scientific standpoint according to Holdmann – it simply hasn’t been done yet. So Chena is looking to pioneer the way yet again, this time in a new frontier, the automotive fuel market.
written by Fred, July 21, 2009
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