VentureBeat

We’re writing a lot about green technologies.

This is not a change of heart. We’re simply following the action.

The latest is that San Francisco firm Expansion Capital Partners has raised more than $55 million for its second fund. Expansion Capital is one of the only venture firms focused on supporting the “expansion” stage of alternative energy companies, helping them move from, say $3 million in annual revenues, to $25 million.

The firm is a crucial, if less-sexy ingredient of the recipe for creating breakthroughs in the important field of green technology. You have the swashbuckling crowd of VCs on Sand Hill Road, who invest $20 million in a company that is pre-revenue, and expect nothing less than a grand-slam. And then you have these guys, at Expansion, who expect decent but not phenomenal progress — and settle for taking a company to the next step. Founder Mark Donahue tells us the firm will soon announce two more investments.

Certain sectors of green tech “are hot, some might call them frothy, but they’re quite limited,” he said, referring specifically to solar and bio-diesel. He said valuations in those two areas are “out of line.” But there are other areas, such lighting energy efficiency, where a company with similar business traction as one in solar may be valued at one-fourth that of the solar company.