Sustainability is a popular buzzword these days, but it has been part of Wendi Goldsmith's vocabulary since she founded Bioengineering Group in Salem, Massachusetts, in 1992. The company helps clients such as the Department of Defense, Target, and MIT embrace green building and design practices. Bioengineering Group brought in revenue of $9.1 million in 2009, earning it the No. 932 spot on the 2010 Inc. 5000.

I love proving that, contrary to popular opinion, the things that work well economically are also the best ecological answers.

One of our big projects is working with the military to implement energy- and water-conservation policies on five bases. We've helped them realize that when you have local renewable energy sources, you not only make the climate better; you also have fewer security threats. We also have a project with the Vancouver Canucks, who want to use the waste heat created from making ice to warm the arena.

I think the recipe for success is curiosity mixed with humility. When we dig deeper, we find that many of the things that we assume are true are actually false.

The building we work in was an abandoned building that we reclaimed 11 years ago. We were the first firm in the area to use sustainable design to refurbish a building, and it helped turn around the neighborhood. It was also a great investment strategy.

Our firm received an award in October, and the prize included dinner with Warren Buffett. When I told him what I did, he told me, "You are in such a great space. You'll never run out of business." It's amazing when the Oracle of Omaha tips his hat to you.

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