Google flicks pennies down geothermal well

Deep hot wet cracks = green dreams

Google, the company which has conscripted everyone on the internet to be its Web 2.0 free-content providers, has decided to give something back. The firm will spend $10m - almost a thousandth of a year's ad revenues - to kickstart geothermal power.

According to Google:

The heat beneath the earth's surface is essentially an unlimited resource ... Enhanced Geothermal Systems, or EGS, expands the potential of geothermal energy by orders of magnitude.

EGS is a big challenge, but with the potential to power the world many times over, it demands our immediate attention ... We ask the President and Congress – what are we waiting for? The current funding for the federal geothermal program - $20 million for 2008 - is grossly inadequate ...

The EGS push is implemented by google.org, the ad behemoth's philanthropy arm, under it's RE<C initiative (that is, Renewable Energy cheaper than Coal). The thinking is that huge amounts of heat could be liberated from deep inside the earth's crust, 3 to 10 km down, rather than using traditional geothermal techniques which use energy from hot springs and so on much nearer the surface.

With EGS, the idea is to drill deep down, and squirt colder water out of the drill pipe. This would crack the hot rock around it, allowing water to be circulated through the cracks and so become very hot. The hot water would then be moved back to the surface and used to drive turbines, so generating electricity in a nice clean fashion.

The really good thing about EGS as compared to other renewables is that it could be on constantly, running at high load factors. Thus, EGS shouldn't require expensive, dirty gas turbine backup or prohibitively vast pumped-storage systems like wind, solar etc. It should deliver something close to its installed capacity over time, like fossil or nuclear and unlike other renewables, potentially bringing down the cost of geothermal 'leccy. Geothermal technology will never make spaceships better, the way nuclear might, but that's about the only criticism you can make of it on other than economic grounds.

Overall, it sounds like a winner. That said, geothermal power is a very old idea and has never so far been able to earn its keep except in rare locations where the heat is close to the surface already. EGS in outline is a pretty simple idea - why has nobody done it before, if it's so easy? Nobody doubts that huge amounts of thermal energy are present deep in the Earth's crust - but can it really be extracted at a reasonable cost? If EGS can genuinely be cheaper than coal, why is google.org even bothering with solar, wind et al? If $20m from the government is "grossly inadequate", surely $10m from google.org is too.

The truth would seem to be that in fact there hasn't been any radical breakthrough in geothermal, and it remains unlikely that it will be cheaper than coal while there's any coal left. The chaps at google.org don't appear to have any serious belief that it will. Rather, they seem to value geothermal more for its reliability than its potential to be cheap, perhaps to help with the baseload issues which plague most fully-renewable energy strategies.

All that said, however, if geothermal worked it would be almost without downsides - a bit like nuclear fusion power. Like fusion, EGS seems to be a bit of a long shot, but it would be so great if it worked that it's surely well worth looking into. Google's reluctance to put its money where its mouth is ought to draw cynicism rather than adulation. Nonetheless, there's nothing wrong with the basic idea this time. ®