22 November 2011—Gasification power plants can now vaporize municipal waste to generate renewable power with a greatly reduced risk of the dioxin emissions that soured neighborhoods on waste incineration in decades past. Nevertheless, pushing gasification technology to commercial scale has proven tough, especially in North America. Equipment-jamming trash, low electricity prices, and enduring community opposition to any facility that resembles an incinerator have derailed every proposed project in the United States and Canada to date.
This year’s casualty was Boston-based gasification developer Ze-gen. Its innovative technology uses molten metal to turn trash into syngas (a combination of carbon monoxide and hydrogen), which is subsequently burned to generate electricity. Ze-gen’s gasification system was profiled optimistically by Spectrum in 2010, but the company scrapped plans for a plant in Massachusetts that it had vowed to complete by the end of 2011.
Hope for a breakthrough now rests with Canadian gasification firm Plasco Energy, which is on the verge of commercializing a new technology centered on electric-arc plasma torches. The trash is heated to break it into crude, impure syngas, which is then zapped with plasma torches to further refine it. The remaining impurities are siphoned off and run back through the system until only pure syngas and pellets of slag—suitable as building material—are left. The syngas powers a generator, and waste heat is fed back to break down more trash.
What distinguishes Ottawa-based Plasco, besides its gasification process, are the partnership it has with its hometown, where it hopes to begin building a plant this year, and a promise from the province of Ontario to pay a premium price for the plant’s power.
One thing is certain: There is little risk that plants such as those run by Plasco and Ze-gen will run out of feedstock. While cities in the United States produced roughly the same amount of waste in 1998 and 2008, the proportion they sent to landfills grew by 8.2 percent over that decade at the expense of both recycling and waste-based power generation, according to the most recent "State of Garbage in America" report from Columbia University’s Earth Engineering Center. In all, landfills absorbed 69.3 percent of waste in 2008, compared with just 6.7 percent sent to incinerators and 24.1 percent sent to recycling. (The U.S. Environmental Protection Agency, which reported a decline in landfilling and a rise in recycling over the same decade, acknowledged potential flaws in its data this summer.)
Some environmental groups such as the Sierra Club oppose waste-based energy, seeing it as diverting resources from recycling. In contrast the Energy Recovery Council, a Washington-based trade group, commissioned a 2009 analysis that found that communities with waste-to-energy plants actually recycle a higher proportion of their trash than the national average.