Here is another quote from a 5 Dec 05 article in HBS Working Knowledge entitled "VCs Survey Post-Bubble Opportunities" by Julie Hanna.   I encourage you to read the whole article for the context:

What about future trends, asked Sahlman. Many venture capitalists made money in enterprise software, until the space was saturated. Will venture capitalists have an impact in fields relating to healthcare, education, and the environment—all areas that show a great demand for new solutions?

"Clean energy is big on the West Coast," said Reiss. "Venture capitalists haven't traditionally invested in those areas that you mentioned . . . but given the amount of money that's in the business, somebody is going to try, and somebody will be right."

"Those spaces that you mentioned don't fit the venture profile for time frame and liquidity," said Kapoor. "They require a ten-year, $100 million investment. With that said, the profile around energy, particularly solar, is starting to look more standardized."

Bottom Line: Having pitched clean energy on the West Coast, I know it is a hard sale. As they note, there is some traction in solar. Target the investors with a track record in the area. But be prepared for the long haul as VCs learn the technology and the business models.