STEAMING UP CALIFORNIA'S FUTURE
Geothermal power, another alternative energy source, has also been enhanced with increased awareness of its activities recently with the AltaRock project. AltaRock plans to use geothermal energy as part of its Engineered Geothermal Systems (EGS) project, which is located at the Northern California Power Agency (NCPA) Geysers Power Facility in northern California and has received a grant from the U.S. Department of Energy. According to AltaRock, the EGS technology differs from that of previous projects as it does not require natural hot-water reservoirs underground, but can create them using water injections.
Choosing a site with hot basement rock, usually found in areas prone to earthquakes, AltaRock plans to produce continuous electricity, as opposed to other alternative energies that have some variability. To do this, the company will utilize a well that is 2 to 3 miles deep where water can be pumped down to create fissures in the rock. Since the stone is heated by magma from the earth’s core, AltaRock asserts that it provides a good heating system for the water that will circulate there. From that point, the water will be pulled back up to the surface, which results in lower pressure and steam-generation. The steam will revolve turbines, generating electricity. The cool water will then be sent back underground to repeat the process.
According to a study by MIT, in 50 years, EGS has the potential to cover up to 10% of America’s electrical consumption at prices comparable to those of fossil-fueled electricity. AltaRock aims to utilize an existing NCPA Geysers well and dig a new one to work with the underground fracture system.
According to a New York Times story, a similar geothermal project took place in Basel, Switzerland, but was forced to halt activity due to an earthquake generated by the project. The 2006 earthquake measured 3.4 on the Richter scale and created a city-wide scare. Because of this event, AltaRock has made safety a priority and chose a location, the Geysers, which has been an active geothermal site for 44 years. The location also has a relatively small fault that, according to the company, generates small earthquakes. AltaRock does not expect these small earthquakes to be disruptive, and its studies predict the largest-estimated earthquake to be 10 times smaller than the one experienced in Basel.
In addition, AltaRock has installed precautions such as underground seismic monitoring devices and controls designed to halt activity if necessary. Rock fracturing will occur at a lower pressure than it was in Basel, and a pressure-relief option can stop the project as a safety measure. The company expects its EGS-patented designs to keep the project safe and under control.
Besides these safety measures, AltaRock has kept area residents updated about their activities and set up a ground motion sensor designed to offer seismic information online.
YOUR NEXT-DOOR TURBINE
Two employees of the U.S. Department of Energy’s Ames Laboratory, Rebecca Shivvers and John Clough, have made the jump to home wind energy with the installation of their own residential wind turbines. Although hybrid cars and energy-efficient products have become more popular, home wind power has not yet gathered a large following.
Labeled a pioneer, Shivvers claims the desire to be self-sufficient drove her to adapt her home to wind power. Clough cited not only the green aspect of wind energy, but also the federal government’s Recovery Act, which allowed 30% of the bill to count as a tax deduction. Both Shivvers and Clough noted this act as a major incentive to their plans, and Shivvers added that the lack of an Iowan sales tax contributed as well.
They have garnered attention from the media, with Shivvers featured on the Des Moines WHO news station, and Clough on Iowa Public Television’s Market to Market program. This coverage led to increased public awareness of the wind turbines, and both Shivvers and Clough noticed considerable attention by their neighbors and strangers, who have expressed interest in the technology by seeing it either on television or driving by their houses. In fact, Clough first received information and guidance from a nearby resident who owned a turbine, who partly inspired his project.
Both home-owners experienced obstacles to their progress, and Shivvers had to upgrade her turbine’s structure to keep it efficient and safe. Specifically, her original four-cylinder turbine had technical problems with wobbling, spinning too fast, and finally stopping altogether due to grid voltage. The company kept track of these difficulties and upgraded the structure to a five-cylinder, thicker monopole. Each cylinder is situated inside another like Russian nesting dolls, varying from 11 to 18 inches, providing added strength and stability to the turbine.
Another obstacle, said Shivvers, was obtaining a $1 million insurance policy for the electric company, which proved difficult as a residential home-owner looking to install a wind turbine. Clough also noted that extensive research was necessary before the turbine could be installed. Overall, Shivvers determined that the process took a total of six months, but could be reduced to one month.
The move to residential wind power differs since it is not only industrial, but is being adapted for home use. Clough, however, pointed out that although it is green technology, the wind turbine cannot cover all of the home’s electricity needs, since wind power is variable. It is necessary, then, to have other means of power available for the household, in addition to the turbine.
Shivvers added that residents need plenty of space for the turbine as well. Both of their turbines are 50 feet tall, and Clough’s blade diameter reaches 12 feet. On a windy day, Shivvers calculated 25 kilowatt hours of energy. For Clough, however, a calm day in the summer only generated 5 kilowatt hours, showing the variability of wind power. Both Shivvers and Clough have the same computer software installed in a wireless box that tracks the tower. This device monitors a variety of factors, including the amount of electricity production, a continuously updated chart of current power generation, and carbon savings in comparison with that of regular electricity.
Sandia National Laboratories
http://www.sandia.gov/index.html
SLAC National Accelerator Laboratory
http://slac.stanford.edu/
AltaRock Energy
http://www.altarockenergy.com/about.html
Ames Laboratory
http://www.ameslab.gov/
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