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SCOTT JAGOW: More people are investing in clean technologies like solar power and biofuels. Last quarter, those investments hit a record level. From the Marketplace Sustainability Desk, Sam Eaton reports.

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SAM EATON: Venture capital investments in clean-tech rose to a record $843 million.

That's the eighth consecutive quarter of growth within the sector, which includes everything from renewable energy technologies to transportation to water purification.

Joel Makower with the research firm Clean Edge says there's a simple reason for all this growth.

JOEL MAKOWER: Energy prices, energy prices and energy prices.

But Makower says dig a little deeper and there are signs of a maturing industry.

MAKOWER: There's been a groundswell of garage tinkerers, of university labs, all sorts of researchers inside corporations that have been developing clean technologies for the past four or five years and we're finally seeing the fruits of those labors come into the business venture stage.

That doesn't mean the market is free from growing pains.

One investment index which tracks shares of clean-tech companies dropped 11 percent in the second quarter.

I'm Sam Eaton for Marketplace.