That whole "Google operates a diverse business plan" idea is getting a weird new spin at the moment--news has surfaced that the search engine giant is working hard to improve the tech behind solar thermal heating systems.

Technically what Google's trying to do is improve the cost of making heliostats--those neat arrays of reflecting devices that concentrate incoming solar energy and then use that energy to power a steam-turbine--by a factor of three or four. Key to making the devices work is the efficiency of their mirrored surfaces: Higher reflectivity equates to more solar energy reflected and thus a higher energy input into the heat-exchanger that drives the turbine.

And it's precisely at this point in the design that Google wants to help. High reflectivity is tricky, and relatively expensive you see. Mirror technology has been around since forever, with the originals being low-reflectivity polished bronze or silver--their low reflectivity meant they weren't much use with the artificial light available at the time. Plate-glass and mercury mirrors, much closer to the modern mirrors we know, have been around since they were invented in 16th Century Venice, and had a reflectivity of greater than 50% of incoming light...but it's only with modern advances that reflectivities of 95-99% have been possible. But these mirrors are expensive.

So Google's working on "very unusual materials" for both the reflective surface and the substrate the mirror is coated onto, according to Google's Green spokesman Bill Wiehl. The company doesn't have precisely the technology it's chasing after yet, but it's confident that in a matter of months they'll have prototypes "cheaper than what companies in space are using."

If you're surprised that Google--primarily a search engine and advertising company--is involved in issues like this, then perhaps you shouldn't be. Back in 2007 Google announced it would invest in technology that would produce electricity from clean sources that would be cheaper than coal, and back in mid-2008 it even invested in Aptera, the company behind the quirky electric car we've seen much about in the news. Google.org, the charitable arm of Google, has invested in AltaRock Energy's geothermal technology, eSolar and Brightsource's solar thermal work, and Makani Power's kite energy system. The organization has also filed a patent for a wave-powered floating data centers.

This move is just the latest in Google's (slightly) philanthropic quest for cleaner power--a quest that, of course, will likely net the company much cash if it hits on a successful technology that ends up being key to the green-power future.

But what's interesting about this venture is that Google seems to be stepping on the toes of some of the companies it has invested heavily in, namely eSolar ($130 million investment) and Brightsource ($115 million investment). And since Bill Weihl, Google's green energy czar, said yesterday at the Reuters Global Climate and Alternative Energy Summit that he was disappointed with the lack of innovation in the solar thermal space, it's puzzling as to why the company invested in eSolar and Brightsource at all.

We'll find out what Google has planned soon enough--the company will have a working prototype in the next few months.

Additional Reporting by Ariel Schwartz

[via Reuters]