Photos: Green tech grows in Boston

Down the road from GreatPoint Energy's coal-to-natural gas plant is Ze-Gen, which is also using gasification but with a different feedstock: garbage.

Ze-Gen is testing a method to use high-temperature gasification on construction debris, a process that makes a gas that can be burned to make electricity.

IST Energy is another company that plans to turn trash into energy but with units big enough to fit onto truck flatbeds.

Photo by Ze-gen

Caption by Martin LaMonica