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USGS finds hot prospect on Akutan Island New geothermal study yields much higher energy estimate; remote Aleutian island hosts active volcano, tiny village, huge fish plant Wesley Loy For Petroleum News
A new study from the U.S. Geological Survey finds much greater geothermal energy potential than originally thought on Akutan Island.
Akutan is in the Aleutian chain, just east of Dutch Harbor. The island is home to a tiny village as well as the Trident Seafoods Corp. processing plant, one of the country’s largest.
The island also has one of the most active volcanoes in the United States.
Interest in Akutan’s geothermal energy potential stretches back decades. Like much of outback Alaska, Akutan is highly reliant on expensive and polluting diesel fuel to generate electricity.
In July 2012, USGS field researchers conducted a five-day survey of the hydrothermal system on Akutan Island.
“The results of our study confirm the existence of a substantial geothermal resource on the island,” says a USGS report released Jan. 9.
27 eruptions The Akutan volcano hosts a geothermal system that includes a fumarole field on the flank of the volcano, and a series of hot springs that discharge close to sea level on the northeast side of the island, USGS said. A fumarole is a steam vent.The volcano has erupted at least 27 times since the late 1700s. The most recent eruption was in 1992, followed by a “seismic crisis” in March 1996.
In the past few years, industry-led geophysical studies and test drilling had proven the existence of a geothermal resource, the USGS says.
Reconnaissance surveys of the hot springs on Akutan Island date back to 1953.
“The first detailed geochemical and geophysical investigations to assess geothermal potential occurred during the early 1980s,” the new study says. “Additional investigations at Akutan took place in 1996, several months after the seismic crisis. Studies at Akutan beginning in 2009 were related to renewed interest in geothermal development of the Akutan hydrothermal system for use by the City of Akutan and other population centers on the island.”
During the five-day survey in July 2012, samples of gas and water were collected from the hot springs, and gas was collected from fumaroles on the flank of the volcano and from steaming ground on the cone inside the summit caldera.
Promising results The geochemistry of the hot springs on Akutan Island was studied in detail for the first time since the early 1980s.
“The results from this study document higher concentrations of hydrothermal components in the hot spring waters and an increase in water discharge from the hot spring system,” the USGS says in a news release on the study. “The current heat output of the hot spring system is estimated at 29 megawatts — nearly ten times higher than measured in the early 1980s. This large increase may reflect the volcanic and seismic events of the 1990s, and if so, it cannot be considered a short-term anomaly. Modern geothermal plants could use this heat to generate several MW of electricity. One MW of electric power would supply the needs of about 750 homes.”
A geothermal reservoir is presumed to underlie the fumarole field, and a chemical geothermometer yields temperatures near 356 degrees Fahrenheit for the aquifer that feeds the hot springs, the USGS says.
“Geothermal development for electrical power generation could take advantage of either a high-temperature, but probably deeper resource, or a moderate-temperature resource at relatively shallow depth,” says Deborah Bergfeld, a USGS geochemist and lead author of the report.
The USGS doesn’t go into the cost that would be involved with a geothermal energy development on Akutan. Presumably, the price tag would be many millions of dollars, with the project requiring some sort of government subsidy.
The 18-page report and photos are available online at http://on.doi.gov/1dhG0zh.
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