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USGS study hints at geothermal energy potential for Akutan

  • Author: Joseph Miller
  • Updated: September 28, 2016
  • Published February 12, 2014

A recently published study of geothermal energy sources on Akutan Island indicate the resource holds significantly more potential than previously thought.

The U.S. Geological Survey published the results of a geochemical study that was conducted on Akutan Island in 2012 that confirms the potential for the development of geothermal power on the island.

The USGS reports that the results from the study show higher concentrations of hydrothermal components in the hot spring waters and an increase in water discharges from the hot spring systems. In the early 1980s several studies were done on the island in hopes of finding a potential source for geothermal energy. This most recent study has found the current heat output from the hot spring system on the island is estimated around 29 megawatts, almost 10 times higher than the heat output that was recorded in the early 1980s. If the geothermal energy on Akutan Island were to be harnessed by a modern geothermal energy plant, the heat output could produce several megawatts of electricity. One megawatt of electricity can be used to supply the electric needs of about 750 modern homes.

Many potential factors go into determining whether a place like Akutan Island is a candidate for geothermal development, however. According to Deborah Bergfeld, a USGS geochemist and the lead author on the report confirming Akutan Island's geothermic potential, some of these considerations have nothing to do with the scientific aspects but rather on social and economic ones.

"The economy drives a lot of it in regards to determining whether a place like Akutan Island has geothermal energy that can be used," said Bergfeld. "But that is beyond our purview. Some other things that are involved include having a resource as well as having a need for the kind of resource that we find there. Beyond that, our part of it is to determine whether there is potential for the heat to be used or mined, which is what our study was focusing on. We determine whether there is evidence in the gas samples and the water samples that suggest that this resource is generating enough heat for it to be used for geothermal energy."

The potential was first recognized on the island when a significant amount of chloride was measured coming up from the hot spring systems.

"We were assessing a couple of different components in this study, but most specifically chloride in the waters," Bergfeld said. "We know that chloride in the waters would most likely not be coming from atmospheric sources, but rather from a magma body or the hydrothermal system. By looking at those values in the water, and looking at those samples and comparing them to what was found in the 1980s has shown us that there is a whole lot more than there used to be."

The amount of heat that has been recorded from underneath Akutan Island, which was measured at 29 megawatts, is not necessarily the amount of energy that could be utilized by a geothermal energy plant. There is a significant amount of power lost in the process of converting geothermal heat into electricity, so despite the amount of heat energy that contributes to the hot spring system on the island being considerably hotter than the reactor of a typical naval nuclear-class submarine, the amount of electrical energy that could be harvested from the geothermal system would only register to a few megawatts of electricity.

"There are always losses when producing temperature contrasts and measuring how much energy could be harvested from a system like this," said Bergfeld. "Back in the 1980s, there was a big push in the scientific community to go out and start conducting research very similar to the research that we conduct today all over Alaska. There were very similar kinds of studies that were done that we've been able to build off of and use because a lot of the methodology was pretty good back then considering how far science has taken us. We can compare the measurements that we take today with the measurements that were taken back then because despite the instrumentation being very different now, the methodology was so similar that we can count ourselves lucky that such careful work was done when this location was first being researched."

While the island's heat energy certainly holds the potential to become a vital energy source for those living on the island and in the surrounding areas, there will most likely not be any modern geothermal energy plants being built on Akutan Island anytime soon.

"The work that we are doing is part of a larger study," said Bergfeld. "It is certainly a positive outcome to see the difference in chloride levels in the water chemistry, but in order for this kind of project to become an economic one, there are still many questions that have to be answered before determining whether this heat source can be converted into electrical energy. There is a still a lot of engineering work that needs to be done, but there are people who are out there working on those kinds of assessments. However, the cost of getting diesel fuel out to the island is getting expensive as well, so we will have to see what the future holds."

This story first appeared in The Bristol Bay Times/Dutch Harbor Fisherman and is republished here with permission.

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