The third annual Global Cleantech 100—a list of the top 100 private companies in clean technology—was collated by combining proprietary Cleantech Group research data with over 6,000 nominations and specific input from an expert panel. These companies represent the most innovative and promising ideas in cleantech—the companies that are best positioned to solve tomorrow’s clean technology challenges.

The 2011 list includes Thayer School spin-off SustainX, Inc.

Founded by Professor Charles Hutchinson and three Dartmouth engineering Ph.D. graduates—Dax Kepshire Th'06, '09, Ben Bollinger '04 Th'04, '08, and Troy McBride Th'01—SustainX is developing technology to compress and store air in a way that helps utilities optimize their use of alternative energy such as wind and solar power.