Energy | Ecotrope

Geothermal Fractures Vs. Hydraulic Fracking: What's The Difference?

Ecotrope | Jan. 24, 2012 4:53 a.m. | Updated: Feb. 19, 2013 1:33 p.m.

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A geothermal project west of Central Oregon's Newberry Volcano National Monument will inject some chemical agents into the ground along with pressurized water that will break open cracks in underground rock. The process may smack of the controversial fracking procedure, but experts say it's a world away.

A geothermal project west of Central Oregon's Newberry Volcano National Monument will inject some chemical agents into the ground along with pressurized water that will break open cracks in underground rock. The process may smack of the controversial fracking procedure, but experts say it's a world away.

I did a radio story yesterday about a doctor in Bend who found a list of chemicals AltaRock Energy plans on injecting into the ground in the Deschutes National Forest along with up to 75 million gallons of water.

The idea is to inject water into the cracks of hot rock 10,000 feet underneath the western flank of the Newberry Volcano, where temperatures can exceed 550 degrees Fahrenheit. That’s a nice heat source for making steam to power a turbine. Geothermal energy is normally generated by pulling preexisting hot water and steam from the ground. But here, AltaRock has proposed a way to generate the same clean energy from a dry hole in Central Oregon.

Here’s a helpful animation of the process, courtesy of the Taiwanese animation studio NMA News:

OPB’s Vince Patton reported that the project will create small earthquakes, most under a magnitude of 1, as the pressurized water opens up natural fractures in the rock and causes them to slip and create underground storage units. Patton asked AltaRock project manager Will Osborn about whether this process is similar to the controversial hydraulic fracturing action that’s being used to extract natural gas from shale rock – and that has contaminated nearby drinking water in some places.

Shattering the earth with fluid sounds a lot like one of the energy industry’s most controversial practices. It draws comparisons to hydraulic fracturing, or “fracking,” where drillers fracture the rock to extract natural gas. Osborn says there’s a big difference.

“In hydrofracking done in the oil and gas industry, they actually shatter the rock. They break the rock and create new cracks, new fractures in the rock. We just inject cold, clean groundwater,” Osborn says. “In hydrofracking they use a mixture of chemicals.”

But then, as Bend family doctor Stuart Garrett recently discovered, AltaRock will, in fact, be using its own mixture of chemicals in the injection process. So, what gives? Is this fracking or not?

Naphthalene disulfa-wha?

First, let’s look at what Garrett found. Here’s a section of the Newberry Geothermal project environmental assessment that details the chemicals known as “tracers” and “diverters” the company plans on injecting underground along with the water.

Here’s Garrett’s reaction, which he sent to the Bureau of Land Management in the form of a public comment:

“Davenport/Altarock has not publicly announced that it will be pumping industrial chemicals (tracers, diverters, mud additives, friction reducers, etc) including naphthalene, safranin, rhodamine, lithium, cesium, rubidium, fluorescein, tobermorite, polymerized plastics, secret Altavert fluids, and other compounds into the wells.

This has not been reported in public meetings, in written materials, or in news articles until the EA came out. More transparency and candor is called for. It is likely that the faulted, fractured and inter-bedded volcanic strata at Newberry will have some degree of leakage. This is especially true with the induced seismicity that is part of the project.

Please provide safety data, toxicology reports, carcinogenicity evaluations, and a discussion of the potential health effects for all materials that will be pumped down the well. While it has been asserted that the proprietary Altavert materials are harmless, the public deserves to know what they are and to make their own judgment. Secrecy does not belong in this EA.”

So … I see all these words Garrett refers to in his letter – including “proprietary technology,” which could be read as “secret fluids” and has also been a major factor in the controversy over hydraulic fracturing.

AltaRock: It’s all non-toxic

But AltaRock President Susan Petty had numerous explanations for the situation:

  • For one, she noted, naphthalene disulphonate isn’t the same as the naphthalene moth ball chemical that has been found to be toxic and possibly carcinogenic. “These materials were deliberately chosen to not be toxic themselves and also to break into component parts that are not toxic. If we looked at a material that did have toxic breakdown products, we rejected it.”

  • The main thing AltaRock is putting into the ground is cold water – millions of gallons of it. The water pressure itself is what opens up the cracks in the rock that allows for the end goal of water passage. The concentrations of other chemicals, used to trace the water and seal the cracks that have been made,  are “very, very dilute” after mixing with all that water.
  • The chemical tracers have been pre-approved by federal agencies. As for the proprietary stuff, she said: “We are using some proprietary materials called thermodegrading zonal isolation materials. These material stopper up the cracks we’ve made already so we can raise the pressure a little bit and make some more cracks. They are, generally speaking, mostly biodigradable plastics – they are polymers, generally, of organic acid. Some of them, in fact, are things that are used in medicine in self-dissolving stitches or self-dissolving pieces that are put in the human body to provide support for broken bones. They’re also used in face creams but the main thing they’re used for is biodegradable cups and stuff like that.”

  • The water will be separated from any groundwater by about 9,000 feet of rock. “The well is 10,000 feet deep, and groundwater in this area starts at 500-600 feet deep. We really don’t see any groundwater below about 1,000 feet – just because the rock is so impermeable here. Any activities we do, therefore, are going to separated by thousands of feet of impermeable rock from the groundwater.”

BLM: This is not fracking

Linda Christian, the Newberry project manager for BLM, backed up Petty’s arguments. She said her agency will know the individual chemicals being used in the proprietary products, which are “like biodegradable plastic bags” that degrade when they get near the heat deep underground.

Christian added that the injection process – which she called hydro-shearing – is shouldn’t be confused with hydraulic fracking, which uses a whole different mix of chemicals to break up shale rock and hold it open.

“It’s an understandable response,” she said. “But hydroshearing isn’t much like hydrofracking. Fracking requires chemicals or sand to hold the fractures open, and that is not at all what’s going to happen with hydroshearing. These cracks already exist. What they may not be is continuous. By adding pressure, mostly with millions of gallons of water going down there, the extra pressure makes the rocks move, so it becomes a continuous conduit of water over hot rock like a heat exchanger.”

If the cracks in the rock start moving vertically – toward the groundwater – she said, “We are going to be monitoring this in real time and in person. We’ll make them stop. Nobody wants these reservoirs to go vertical – or toward the surface. We have a few thousand feet to play with. The minute we started seeing it going in a perpendicular fashion, we would stop injecting and take all the pressure off.”

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