I like the fact that General Electric (NYSE:GE) is getting into the growing field of thin-film solar technology. It's more proof that renewable energy will continue to grow as a percentage of the company's overall business.

I have made no secret of my belief that thin-film solar technology poses a disruptive threat to traditional silicon-based solar cells. On Thursday, GE Energy announced that it had reached an agreement to acquire a minority equity stake in a relatively young solar thin-film manufacturing firm, PrimeStar Solar. It heartens me that GE is joining the field already populated by the likes of First Solar (NASDAQ:FSLR), Energy Conversion Devices (NASDAQ:ENER), and Suntech Power (NYSE:STP).

The company also revealed last week that it had invested an undisclosed amount in a 126.5 MW wind farm being manufactured by Dublin-based Airtricity. This is the third Airtricity wind farm in Texas that GE Energy Financial Services has invested in, bringing its total number of wind farms to 50.

Earlier this year I wrote a piece titled GE Cleans Up in which I outlined GE's push into renewable energy and explained why the company's willingness to invest $1.5 billion in "cleaner technologies" by 2010 made me bullish on the company's long-term prospects.

At the time, I encouraged investors to focus on the company's efforts to grow its nuclear power and cleaner-coal businesses as the most promising short-term ways to profit from global efforts to control carbon dioxide emissions. I stand by that assessment. I felt wind and solar were longer-term prospects. But if GE's actions last week are any indication, GE will have a stronger position in wind and solar sooner than I had originally expected.

In the grand scheme of GE's massive and well-diversified business, these deals are still pretty small potatoes. That said, they do provide strong supporting evidence that renewable energy will continue to grow as a portion of the company's overall business. I reiterate my position that investors looking for a relatively conservative way to play the "cleantech" opportunity should give General Electric a good, long look.

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Fool contributor Jack Uldrich owns shares in GE and Suntech Power. The Motley Fool has a disclosure policy.