Comments on: Hot Rocks

Hot Rocks

Artw — Tue, 19 Aug 2008 13:06:09 -0800

Google goes geothermal with EGS.

By: Tacodog

Tacodog — Tue, 19 Aug 2008 13:33:53 -0800

If I recall, this sounds like the same principle method used in Basel, Switzerland which is blamed for more than a few earthquakes. If I'm wrong, why is EGS better than the technology used in Basel? I imagine there's more than one way to harness geothermal energy without fracturing your rock foundation.

By: mullingitover

mullingitover — Tue, 19 Aug 2008 13:42:57 -0800

This is awesome. I've always thought it silly that we've been using nuclear energy simply to generate heat. We can get all the heat in the world simply by digging a deep enough hole in the ground.

By: Artw

Artw — Tue, 19 Aug 2008 13:48:07 -0800

If I recall, this sounds like the same principle method used in Basel, Switzerland which is blamed for more than a few earthquakes. Yup, according to Wikipedia "Basel is in a known earthquake zone (see Basel earthquake) and sits atop a historically active fault." Possibly not the best placement.

By: mathowie

mathowie — Tue, 19 Aug 2008 15:08:10 -0800

This is great and something I've been following for some time. My father-in-law is an author of the original MIT/DoE report referenced in the older NYT articles and he's been telling me about this for a while. The dream is that you'll basically turn anywhere on earth into Iceland -- a place where you can drill down anywhere and get loads of free energy from heat. Geothermal has been temporary, destructive, and only practiced near volcanic activity zones in the past, but this would basically solve all three problems by making them permanent, available anywhere, and non-destructive. I really hope this tech goes far, it's as close as we'll ever get to free unlimited energy with almost no downside.

By: XMLicious

XMLicious — Tue, 19 Aug 2008 15:09:41 -0800

Does anyone know what the difference would be between EGS and geothermal heat pumps? Is it just a matter of scale?

By: XMLicious

XMLicious — Tue, 19 Aug 2008 15:12:25 -0800

Oh, wait, never mind. I guess geothermal heat pumps are just used for HVAC, not for generating electricity.

By: KokuRyu

KokuRyu — Tue, 19 Aug 2008 16:38:52 -0800

If Basel in Switzerland is known for earthquake activity, how can a geothermal facility be blamed for earthquakes? It doesn't make any sense. And locating a geothermal facility in an earthquake zone is probably safer than locating a nuclear power plant in an earthquake zone (Japan) or a hydroelectric dam.

By: Artw

Artw — Tue, 19 Aug 2008 16:52:09 -0800

There's probably some assotiation between areas with nice hot rocks and earthquake activity, but still: "The Basel earthquake of 1356, also known as the Great Basel Earthquake, is the most significant seismological event to have occurred in Central Europe in recorded history. " - yikes!

By: kcds

kcds — Tue, 19 Aug 2008 17:23:01 -0800

@XMLicious - the two systems have things in common, but there are key differences too. Both systems typically use water or a water-based coolant to transfer heat energy from one place to another, but the temperature difference in the HVAC case between the surface and the bottom of the loop is tens of degrees at most. By designing the system carefully, and with the the right kind of climate, you can choose a temperature at the bottom of the loop (say, 65 degrees) such that it provides cooling in summer and heating in the winter. In many cases, the heating or cooling energy provided by the water is often made more useful with the addition of a small heat pump. With EGS (and other geothermal generating schemes), the heat and temperature at the bottom of the loop are sufficient to generate steam from the water that's down there, so the temperature difference between the surface and the bottom of the loop may be hundreds of degrees. Once the steam reaches the surface, it is used to drive turbines that generate electricity, rather than typically being directly used for heating or cooling.

By: Tacodog

Tacodog — Tue, 19 Aug 2008 17:39:17 -0800

Well, considering the engineers in Basel said upfront that their actions may cause small tremors, sounds like they knew their actions would cause something to happen. Whether it was them or not, who knows. But locating it there...gulp. I sure hope the google deal goes smoothly.

By: Popular Ethics

Popular Ethics — Tue, 19 Aug 2008 18:27:23 -0800

Here's a great paper discussing the economics of EGS [pdf] for anyone who's curious like I was. The short of it is this: for High Grade geothermal resources like those that exist on the West coast, this technology is reasonably competitive (4 to 6 cents US / kw*hr) with gas, coal and nuclear (usually 3 to 5 cents / kw *hr). Low Grade resources will take a drilling technology leap before they'll cost any less than 30 cents / kw*hr, which is even more expensive than photovolatics. Of course this depends heavily on interest rates since EGS (like nuclear power) is very capital intensive. But I don't think Google will have any trouble finding the money, since they are sitting on a giant mound of cash, and have a corporate goal to invest in socially beneficial tech.

By: Popular Ethics

Popular Ethics — Tue, 19 Aug 2008 18:31:06 -0800

Reading the linked article again, it doesn't look like Google is looking to deploy EGS on their campus so much as giving seed money to other researchers. In that case, ignore the last sentence of my previous post.

By: biffa

biffa — Wed, 20 Aug 2008 04:24:04 -0800

Yup, according to Wikipedia "Basel is in a known earthquake zone (see Basel earthquake) and sits atop a historically active fault." Possibly not the best placement. Nah, that's rubbish, Iceland gets 15% of its electricity and ~99% of its space and water heating from geothermal power stations and the stations are specifically sited at geologically more active sites. This one at Nesjavellir, for example, is right on the Mid Atlantic Rift which runs through the centre of Iceland. This tends to mean you have to do less digging to get to a depth where you can get useful temperatures. When we visited they mentioned that they record literally thousands of earthquakes (above 0.5 on the richter scale) every year and that practically all of these do not present a problem. I should probably point out that sites as useful as Iceland's are quite rare.

By: Phalene

Phalene — Wed, 20 Aug 2008 05:14:33 -0800

What are the draw backs to geothermal? I mean, as soon as I hear 'limitless energy' I think of the 1960's advertising for drag net fishing as a means to feed the entire world. Mini earthquakes aside, are their any draw backs to punching small holes in the planet? Or does this only really work on a natural vent, anyway?

By: Popular Ethics

Popular Ethics — Wed, 20 Aug 2008 11:11:01 -0800

Phalene: see my earlier post. It's expensive.

By: Artw

Artw — Wed, 20 Aug 2008 12:47:42 -0800

Aliens nest in them. Also they burst and send lava-flows everywhere.