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Geothermal is a Red-Hot Topic

Many people in Hawaii think geothermal electricity is a great renewable-energy idea, unless you happen to live in Puna, the epicenter of both geothermal and the opposition to it.

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Shakeup in Switzerland

Although Markus Haering’s  geothermal energy project was partly funded by the Swiss government, he was arrested when his test well triggered earthquakes beneath Basel in 2006.

The resulting 2,000 damage claims totaled $9 million.

It seemed like a good idea: inject cold water into hot rock formations three miles beneath the city, bring the resulting steam up to run turbines and generate power. As the first to try this new technology, the project held the interest of geothermal supporters around the world, including the U.S. Department of Energy.

Most of the quakes were too weak to be felt at the surface, but 30 were strong enough to crack walls and cause other damage, the largest reaching 3.4 on the Richter scale. To face jail time, Haering would have had to be convicted of intentionally causing the damage.

But, no malice was found and he was acquitted. GeoPower Basel, the parent company, settled all the claims.

Expressing the disappoint-ment of the renewable energy community, Nicholas Deichmann of the Swiss Seismological Service told the New York Times, “As for Basel, it is clear that this project is buried.” But he held out hope that the technology could still be applied in less populated areas. It is. Called enhanced or advanced geothermal exploration, it’s a form of hydraulic “fracking” that is being tested in Oregon, California and other locations.

 


 

Growing Power in the U.S. West

There are places on the mainland where geothermal power is produced near homes and workplaces, just as in happening in Puna. None provide exact comparisons with Puna, but it is worthwhile to examine some examples from the U.S. West to see the possibilities and challenges of geothermal power in or near populated areas.

Part of the geothermal Steamboat Complex in Reno.

Photo: Courtesy of Ormat

Nevada – On the outskirts of Reno is a series of geo-thermal generators called the Steamboat Complex that came on line in 1988.  Now owned by Ormat, the same Israeli-based company that operates Puna Geothermal Ventures, it provides 86 mw of electricity, enough to power the entire residential load of the city.

Steamboat consists of seven plants, four of which are actually within the city limits, though none are adjacent to homes. The brine comes up from 500-3,000 feet at a temperature of 300-400 degrees, comparable to temperatures at Puna. However, despite repeated emails and phone calls, Ormat would not tell Hawaii Business about the contaminants in the brine, so we were unable to compare that with Puna.

Nevada is becoming America’s poster child for geothermal energy. Michael Yackira, CEO of NV Energy, a Nevada power utility, reports that the 550 mw of geothermal power currently produced in the state will jump to 1,000 by early 2014. That means the state can retire its 1960s-era coal-fired power plants five to seven years early.

Oregon – The Oregon Institute of Technology, with some 4,000 undergraduate students, overlooks scenic Upper Klamath Lake in Klamath Falls. As OIT students eagerly tell you, their university was the first in the U.S. to heat its buildings with geothermal warmth. The water, averaging 170 degrees, is pumped from an underground aquifer and piped beneath floors or through metal radiators to keep the buildings warm through the cold Oregon winters.

As geothermal technology advanced, Professor Tonya “Toni” Boyd asked, “Why can’t we be the first U.S. university to become electrified by our own water supply?” The university administration gave its approval, as did the city of Klamath Falls, with no additional geothermal safety restrictions.

At the Geothermal Energy Expo In Las Vegas on the last weekend in September, Boyd told Hawaii Business that the first geothermal generator at OIT began producing 280 kw in 2009.  A second 1.75 mw generator will come on line in April 2014, augmented by solar PV panels. OIT plans to be the first U.S. college campus to be fully self-sufficient in electric power by the early summer 2014, with excess power fed into the local grid.

Why do students and faculty not have the same fear as Puna residents if they live and work right next to their power supply? The answer lies in the temperature of the water. At 170 degrees, the water brought up from 500-700 feet beneath the surface contains very few contaminants. At OIT, hydrogen sulfide measures at around two parts per million, not enough to even consider hazardous. During initial tests at Puna in 1981, the brine was discharged at 300-400 degrees with H2S at 800 parts per million, and those levels should be similar today, says Professor Donald M. Thomas, geochemist and director of the Center for the Study of Active Volcanoes at the University of Hawaii.

The water/brine is reinjected in both Puna and in Klamath Falls. In Puna, it is to reduce the toxic emissions. In Klamath Falls, the city ordered the used water to be re-injected back into the ground after it was originally merely poured down the drain. The change in rules wasn’t because of concern about pollution, but subsidence. Remove enough underground water without replacing it creates a risk of sinkholes or cave-ins.

You may wonder, “How can OIT run generators without steam? You don’t have steam at 170 degrees. It has to be at least 212 degrees.” As in many geothermal locations, OIT’s power generators use a separate fluid – a petroleum product called isopentane – that boils at a mere 82 degrees. The hot water heats the isopentane, which drives the generators. This is called a binary system and may be used anywhere the ground water temperature is too low to boil water. In fact, Puna Geothermal Ventures uses a binary system to generate 8 mw of its current 38 mw output in Puna. Six of Steamboat’s seven systems are also binary.

 


 

Preparing for Emergencies

Hydrogen sulfide (H2S) is a gas emitted from active volcanic vents. It can also be released from a geothermal site and drift downwind if there is a leak or accident. Here is how Hawaii County emergency services say they will respond to geothermal leaks:

ALERT
H2S concentration of 0.005 ppm is detected at plant perimeter. Odor may be detectable
  • Fire Department and Civil Defense are notified and stand by to respond.
ADVISORY
An H2S release persists and is not controlled within 20 minutes
  • Fire Department responds with the nearest regular company as well as the HazMat unit.
  • Civil Defense will issue an advisory via its mass notification system informing people in Lower Puna that an event has occured and that first responders are on site to monitor further developments.
WATCH
Plant staff is not able to immediately control the release and H2S levels continue to rise
  • At 1.0 ppm or earlier, Civil Defense will issue a notice via mass notification recommending that people who are medically fragile or discomforted to leave the area or remain indoors.
  • Fire Department will use current weather and situation conditions to model the dispersal of H2S to determine areas where evacuation may be recommended.
WARNING
Plant staff is unable to manage the release, sound levels are excessive, and H2S levels continue to rise
  • At 10.0 ppm or earlier, an evacuation notice will be issued for the affected area via mass notification, radio and neighboring canvas.

 

Source: Hawaii County Brochure

 


 

Danger Levels

The health effects of H2S depend on both the concentration and the duration of exposure. Low levels may irritate the eyes and the respiratory tract. High levels can have more serious impacts. Here are the Environmental Protection Agency’s Guideline Limits:

10 min 30 min 60 min 4 hours 8 hours
LIMIT 1: People could experience discomfort and irritation, but effects are transient and reversible upon cessation of exposure.
.75 ppm .60 ppm .51 ppm .36 ppm .33 ppm
LIMIT 2: People could experience serious, long lasting adverse health effects or an impaired ability to escape.
41 ppm 32 ppm 27 ppm 20 ppm 17 ppm
LIMIT 3: People could experience life-threatening health effects or death.
76 ppm 59 ppm 50 ppm 37 ppm 31 ppm

 

Source: Hawaii County Brochure

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