Tag Archives: geothermal energy

Update on Hawaiian lava eruption

Link here. This news article is particularly informative, as it includes a map that outlines the extent of the lava flows and what they have engulfed, including the most recent flows that are threatening a geothermal power plant that has been providing the Big Island about 25% of its power.

“Lava flow from Fissures 7 and 21 crossed into PGV [Puna Geothermal Venture] property overnight and has now covered one well that was successfully plugged,” declared the Hawaii Civil Defense Agency in a statement released on Sunday, May 27 at 6:00 pm local time. “That well, along with a second well 100 feet [30 meters] away, are stable and secured, and are being monitored. Also due to preventative measures, neither well is expected to release any hydrogen sulfide.”

Those preventive measures included a complete shutdown of the geothermal plant, the capping of all 11 wells, and the removal of some 60,000 gallons of flammable liquid. Those precautions aside, this is the first time in history—as far as we know—that lava has ever engulfed a geothermal power plant, so it’s all uncharted territory. There’s fear that a rupture of the wells could set off an explosion, releasing hydrogen sulfide and other dangerous gasses into the environment. As of this posting, the lava flows on the PGV grounds have stopped moving.

Environmentalists often promote geothermal power as an alternative to fossil fuels. Environmentalists also sued to prevent this plant from being built because of its proximity to the volcano.

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Big earthquake in South Korea linked to geothermal power plant

South Korea’s second largest earthquake has now been linked by two different studies to the injection of water deep below the surface at a new geothermal power plant.

Perched on South Korea’s southeast coast and far from grinding tectonic plates, Pohang is an unlikely spot for a big earthquake. Before the geothermal plant’s two wells were drilled, there had never been an earthquake there of any significance, says Kwanghee Kim, a seismologist at Pusan National University in Busan, South Korea, and lead author of one study. But while Kim was monitoring the aftermath of an unrelated earthquake in 2016, he began to detect rumbles from Pohang. That prompted his lab to deploy eight temporary seismic sensors at the site, which were finally in place on 10 November 2017. He expected any quakes to be small—after all, the largest previous quake tied to enhanced geothermal power, in Basel, Switzerland, was just 3.4 in magnitude.

It took only 5 days to be proved wrong. “The Pohang earthquake was larger than any predicted by existing theories,” Kim says. Although some initial measures placed the source of the quake several kilometers away from the plant, Kim’s network revealed that the earthquake, and several of its foreshocks, all began right below the 4-kilometer-deep well used to inject water into the subsurface to create the plant’s heating reservoir. Indeed, it appears likely that the well’s high-pressure water lubricated an unknown fault in the rock, causing it to slip and triggering the quake, Kim says.

A second paper, by European scientists who used regional seismic data, reinforces the South Korean team’s results, in particular its shallow depth. That study also points out that an earlier 3.1-magnitude earthquake also took place near the well bottom, increasing the odds of a common source. Satellite measures of shifts in the surface after the November 2017 quake support that idea, says Stefan Wiemer, the second study’s lead author and director of the Swiss Seismological Service in Zurich. It’s clear the locked fault was storing energy that was waiting to be released, Wiemer says. “If that fault would have gone next Tuesday or 50 years from now, we’ll never know.”

The article notes that scientists had previously concluded that injecting water underground for geothermal purposes was okay (since it reduced use of fossil fuels) while doing the same for fracking (to obtain and use fossil fuels) was bad.. The data here actually suggests just the reverse, since fracking has never produced an earthquake as large as the 5.5 magnitude Pohang quake.

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Geothermal energy developers plan to pump 24 million gallons of water into a dormant volcano in Oregon this summer to demonstrate a new way to generate electricity.

Geothermal energy developers plan to pump 24 million gallons of water into a dormant volcano in Oregon this summer to demonstrate a new way to generate electricity.

The irony I glean from this article is this: Pumping water underground to produce energy from geothermal sources (a source liked by the environmental movement) is good. However, pumping water underground to produce energy from gas or oil (energy sources hated by the environmental movement) is bad. And yet, what difference really is there between either effort?

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