All the processes mentioned here are becoming more efficient just as environmental restrictions on incinerators and landfills are tightening around the world. So in the aggregate waste-to-energy will see dramatic growth in coming years, though it isn't yet clear which technologies will be the eventual winners. U.K.-based Alkane Energy, the leader in methane generation plants, is a solid choice in that segment. But as with so many other clean technologies, the innovative smaller players (i.e., the potential growth stocks) face competition from deep-pocketed giants. Garbage giants Waste Management, Allied Waste, and Covanta, for instance, operate dozens of traditional incineration plants and recycling operations and will no doubt aggressively adopt new waste-to-energy technologies as they become viable.

Table 17.1 Waste Management Companies