Where he is right though is the issue of scalability. There are some many ideas out there, that have real world scale issues. Look at ethanol. We are now only at 5% ethanol of gas and have serious logistics issues (stainless steel pipeline anyone ???). And now syngas/Fischer-Tropsch ???
That said, a large part of the VCs and PE investors currently in cleantech would qualify probably as “environmentalist”. Funny though is that at the last Deal.com conference by Goodwin Procter, where he also talked, I did challenge him on the scalability issues of a number of his investments… The guys is good ;)

He is correct in pointing out the intermittent nature of solar and wind make them highly problematic energy solutions. He is also correct that PHEVs do not address climate change (at least not directly).

I do have an issue with him with respect to “liquid bio-fuels”. One can extract twice the energy content from biomass as methane (a gas) than if one instead extracts ethanol, assuming cellulosic ethanol can be made to work. It is true that gaseous fuels are more problematic to deal with, but with this cost savings, this approach cannot be dismissed out of hand. Anaerobic digestion of biomass (including cellulose) to produce methane is a mature technology.