Depending on what news you’ve been following lately, you may (or may not) have heard about Google’s latest initiative. The company’s philanthropic arm is investing a bit over $10 million (US) into geothermal energy. Traditionally, geothermal energy has involved tapping hot springs or geysers. Google is funding research into a more-widely-applicable form of the technology — injecting water into hot rocks, then bringing the resulting steam back to the surface to run turbines that generate electricity.
The system is essentially closed, so it’s non-polluting. That’s not to say, though, that it’s without its drawbacks. To date, these “enhanced geothermal systems” (sometimes called closed systems) have only been built on experimental scales. Oh, and they occasionally trigger earthquakes, too.
Here’s a video from Google explaining the concept: