Google digs deep to exploit geothermal energy

Google is investing $10m (£5.4m) in 'enhanced' geothermal systems — essentially technology for tapping underground heat.

The company says geothermal energy is one of most promising forms of renewable energy.

Through its philanthropic arm, Google.org, the internet giant will invest in two geothermal-technology start-up companies and give a university grant to study the potential of geothermal resources.

The move is part of Google.org's RE<C (Renewable Energy Less than Coal) initiative, aimed at producing one gigawatt of electricity through renewable sources.

Google has invested in solar thermal companies eSolar and BrightSource Energy, as well as wind company Makani Power. In addition, the company has installed a large, 1.6-megawatt solar array and established a plug-in hybrid station at its headquarters, as well as spearheading energy-efficient computing programmes like Climate Savers.

The latest investments are meant to spur development of geothermal energy, which was found to be underutilised in a study by the Massachusetts Institute of Technology last year. Like fossil-fuel power plants, geothermal plants can supply electricity during peak times, while wind and solar have limitations in this regard.

Mixing water and hot rocks
The two companies Google is investing in — AltaRock Energy and Potter Drilling — focus specifically on so-called 'enhanced' geothermal technology.

Typically, geothermal plants tap into existing wells of hot water or steam thousands of feet underground. The retrieved hot water or steam turns a steam turbine to make electricity.

Enhanced geothermal technology pumps water underground to crack hot rocks. The heated water or steam is captured to turn a turbine and then pumped back down underground.

The US Department of Energy said that these advanced techniques can dramatically increase geothermal potential, up to 40 times.

"EGS [enhanced geothermal systems] could be the 'killer app' of the energy world. It has the potential to deliver vast quantities of power 24/7 and be captured nearly anywhere on the planet, and it would be a perfect complement to intermittent sources, like solar and wind," Dan Reicher, director of climate and energy initiatives for Google.org, said in a statement.

Google is putting $6.25m into AltaRock Energy, part of a larger $26.5m second round of investment. First-round investors included high-profile green-technology venture capital firms Khosla Ventures and Kleiner Perkins Caufield & Byers.

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AltaRock Energy is looking to develop a cost-effective method for pumping water underground and recuperating it. It plans to launch a pilot project and is targeting utilities in western US states that have renewable energy mandates.

Google.org will also invest $4m in two separate "tranches" into Potter Drilling, which is making drilling products designed for hard rocks, like granite. The technology can also be used for carbon capture and storage, and nuclear-waste storage.

Meanwhile, Southern Methodist University's Geothermal Lab will get a $489,521 grant to study the size and distribution of geothermal energy resources in North America.

In an FAQ, Google.org said that development of enhanced geothermal systems means that renewable energy "could conceivably be deployed almost anywhere, and is essentially limitless in supply".

Reicher said enhanced geothermal system technology "hasn't received the attention it merits". Google.org is pressing for policies and commercial investment to better encourage EGS development.

Google is also said to have been in discussions with Israeli geothermal company Ormat Technologies.