When my travel-heavy schedule permits, I try to show up at the meetings for my town's Renewable Energy Committee. They're usually a quiet affair, as the committee is a small group of volunteers who help the town assembly look into issues like energy efficiency improvements to the schools, some renewable energy opportunities, streetlight replacements, etc.

So I was pretty surprised to show up last night to find that instead of the usual four-person meeting, there was a packed room of around 20. Why? Because of recent local newspaper articles suggesting that the REC was about to put up a wind turbine at the town's middle school.

I sat back and just watched, and it was a...

For cleantech entrepreneurs who were out raising funds from VCs three years ago, it was easy: Just make the biggest claims possible. Talk about reinventing the entire planet, VCs wanted to think big. Bigger dreams just meant bigger rounds.

These days, market disruption is still a major goal of many VCs investing the sector. But pragmatism, capital efficiency, and execution are the watchwords of the day. This presents the cleantech entrepreneur with a dilemma -- do they talk in very focused terms about a couple of market sub-segments where they know they can do well, or do they talk about massive market disruption but risk coming across as not being serious enough?

For what it's...