AltaRock Taking Geothermal Energy to the Next Level
I haven't done much research on geothermal energy, although I did a post about geothermal heat pumps a while back. But I stumbled upon a company named AltaRock Energy who believes they have a scalable geothermal solution. It looks very interesting.
As AltaRock points out on this page, the nice thing about geothermal energy is its 24x7 availability. I love wind power, but wind has a major achilles heel: the wind doesn't always blow & might not be blowing at the most critical, high demand periods. How can you rely on that? Without major improvements in battery technology (which is very expensive by the way), you can't. The same thing holds true for solar since they sun doesn't help much at night.
Geothermal's problem has been the fact that there aren't that many places that fit the conventional geothermal hot spot description. These are spots that have natural reservoirs of super-hot water deep in the ground. Think Iceland & Yellowstone National Park. We've long known we can tap into those hot water reservoirs, pump the liquid up & use the steam to spin turbines & create electricity. The issue is that there aren't enough of these naturally occurring hot spots to exploit (plus they often reside far away from populated areas).
AltaRock has a solution. They inject cold water at high pressure deep into the earth ("hot basement rock"). The water fractures the rock & essentially creates pathways & areas where the water can pool up. As the water flows through the hot basement rock, it heats up. Hot water is then pulled up to the surface via wells. This diagram below shows how the entire system works:
Underwriting this company's development are major VC firms like Khosla Ventures, Kleiner Perkins, and Google.org. AltaRock just closed a $26 million second round of financing [PDF requires Adobe Acrobat].
I couldn't find any information on costs associated with the AltaRock geothermal system, but the idea seems really interesting on the surface. Who knows? Maybe it's incredibly expensive, or maybe it's an EROEI dog ... but certainly one to watch.