An interesting earth2tech interview with Drew Clark, IBM’s director of strategy for its Venture Capital Group, highlights what a frenzy there is over some renewable energies.

Drew highlights his top 5 most promising start-ups — and also raises concern about a green energy bubble.

Q). What are the 5 most promising startups you are working with?

A). Gridpoint, a smart grid company. Miartech, a Chinese maker of standards-based wireless transmission chip sets that enable the information to flow over the powerlines, Sensicore, an Ann Arbor-based water management company spun out of the University of Michigan. Synapsense, a data center intelligence technology company. Fat Spaniel, a renewable energy accountability company.

Q. Is there a clean tech bubble?

A. Sure. Its over solar and bio. Absolutely. There is a lot of money going in there and it may have some consequences downstream as some profits are taken. But I don’t see enough investment in this other stuff. There is a vacuum around water, and not an over abundance of money in advanced energy management. IBM is mainly concerned with areas that aren’t in the bubble.