Venture capital firms poured $917 million into clean energy companies last year, a 28% increase from 2004, according to a report by Nth Power, a venture capital firm in San Francisco, and Clean Edge, a consultancy. The annual Clean Energy Trends noted that clean energy companies were helped by more than just high oil prices. Solar companies laid claim to the year's three largest tech IPOs worldwide: Q-Cells, SunPower and Suntech Power. The three IPOs raised a combined $800 million.

As a percentage of total venture investments, energy technology accounted for 4.2% in 2005, up from 3.3% in 2004. The authors expect the public markets to open their arms to more than just solar companies in 2006. They pointed to companies making longer-lasting batteries and others dealing in energy-intelligence systems as especially strong candidates. Energy-intelligence systems allow owners to use energy more efficiently through data management, metering or load control.