Meg Cichon and Jennifer Runyon, RenewableEnergyWorld.com
December 11, 2012 | 2 Comments
Best Geothermal Project: Hudson Ranch I (now the John L. Featherstone Plant), owned by EnergySource in Imperial Valley, Calif.
The 49.9 MW Hudson Ranch I geothermal plant, renamed John L. Featherstone Plant, was commissioned in March 2012 in Imperial Valley, Calif. It is the first geothermal plant to go online in the Salton Sea area in 20 years. Recognizing the area's huge potential capacity of reportedly up to 2 GW, EnergySource expects to start drilling for its 49.9 MW Hudson Ranch II project and hopes to start construction in 2013.
The decision to rename the plant after Featherstone was a simple one: A geothermal pioneer in the Salton Sea area since the 1970s and one of the founders of EnergySource, Featherstone has contributed several patents that have influenced plant design, the recovery of minerals from geothermal brine and more.
The $400 million project underwent construction in 2010 and created over 200 construction jobs; it now employs 55 full-time workers. It is working at its full 49.9 MW capacity, and power is sold to the Salt River Project in Arizona under a 30-year PPA.
“The Salton Sea geothermal field is among the world’s largest and highest temperature resources because it lies directly inside an active plate tectonic boundary," said Dennis V. McGinn, president of the American Council on Renewable Energy (ACORE) and keynote speaker at the Hudson Ranch I unveiling.
The Salton Sea landscape posed some difficulties during construction, including heavy mineralization within the brine that threatened to clog the geothermal system. EnergySource partnered with Simbol Minerals to manage an extraction process, which required extra infrastructure to clear the brine. The extracted minerals will then be used to manufacture batteries. The EnergySource-Simbol partnership is expected to continue throughout the construction of Hudson Ranch II.
Best Geothermal Project Runner-Up: PMU Dominica, on the island of Dominica
Geothermal potential in the Caribbean is thought to be substantial, but it remains largely untapped. The island of Dominica is one of the more promising sites, and is believed to have more than 1,300 MW of power potential, and the government is eager to develop the technology and wean itself off of expensive fossil fuels.
The government of Dominica signed an agreement with Iceland GeoSurvey (ISOR) to drill three exploration wells to test for geothermal potential on the island in December 2011. The project was also financed by the French Development Agency (ADF) and the European Development Fund (EDF). ISOR used a slim well concept, which drills holes of four inches or less in diameter to depths of 1,800 meters. Aside from being more economical, slim hole drilling can be used to determine what the resources consist of and if they are usable for electricity production.
Results from the three wells appear to be successful, and researchers are confident that the wells will be hot enough to produce electricity.
“It looks very strong so far,” said Will Osborne of the project team. “The potential, I would guess, is about a couple of megawatts at least, but it’s only partially open. This is just a small diameter test, so for a smaller well, this is a very good result.”
The team will collect resource and environmental data to determine the exact resource capacity for the project.
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