FACTBOX: Venture capital investments in clean technology

LOS ANGELES (Reuters) - Venture capital investments in alternative energy companies have quadrupled in the last two years as firms have rushed to capitalize on growing demand for clean energy sources and concerns about climate change.

Some, however, expect those investments to trail off in the current quarter due to tumbling oil prices and a global credit crisis. Here are some key facts about venture capital investments in "cleantech":

In the United States, venture capitalists invested $1.036 billion into cleantech in the third quarter of this year, compared with $886.4 million in the same period last year and $507.6 million in the third quarter of 2006.

U.S. cleantech investments made up about 15 percent of the $7.131 billion venture capitalists invested overall in the third quarter, up from about 11 percent of the total in the same quarter the previous year.

Venture investments in cleantech companies in North America, Europe, China and India reached a record $2.6 billion in the third quarter, up 17 percent from the previous quarter.

The most active funders of venture-stage cleantech companies in the third quarter were Boston-based RockPort Capital Partners, Web search leader Google Inc, and Silicon Valley firms Advanced Technology Ventures, Kleiner Perkins Caufield & Byers and Khosla Ventures.

The top five venture capital cleantech funding rounds this year were $300 million for San Jose, California-based thin-film solar company Nanosolar, $200 million for San Jose-based thin-film solar panel maker SoloPower, $176.5 million for Finnish wind turbine maker WinWind Oy, $140 million for Santa Monica, California-based solar thermal company Solar Reserve, and $133.7 million for German thin-film solar company Sulfurcell Solartechnik.

Sources: Thomson Reuters, The Cleantech Group (Reporting by Nichola Groom; editing by Carol Bishopric)