7. Johnson Controls and Honeywell
Yes, it's cheating to declare a tie, but these two companies are mentioned in tandem quite a bit. In fact, I can't think of the last time someone mentioned Johnson Controls without adding "...and Honeywell" and vice versa.
The two companies are primarily known for building management systems, a growing market that will likely undergo a rapid evolutionary spurt, but they have other interests, too. Honeywell is the parent of UOP, which is leading the charge in developing catalysts required to transform feedstocks into "drop in" fuels like renewable diesel, jet fuel, and gasoline that require no changes to fuel infrastructure or fleet engines.
Johnson, meanwhile, is participating on the retrofit of the Empire State Building, while its battery group received $299 million from the DOE to develop nickel cobalt batteries for hybrids. The joint venture Johnson Controls-Saft makes lithium ion batteries for Ford.
The company also likes solar steam. "It is about a 40 percent efficient process. Solar thermal has advantages we need to capitalize on," Don Albinger, vice president of renewable energy solutions, told us last year.
Another interesting, and ancient, company that will loom large in green building: Alcoa.