Emerging Waste-to-Energy Technologies: Solid Waste Solution or Dead End?

Incineration is a dirty word in the United States, at least where trash is involved. We’ve been burning municipal solid waste (MSW) since the 1880s. But the dawning of the environmental movement eight decades later cast new light on the nitrous oxides, dioxins, and other chemicals emitted from as many as 600 mass-burn incinerators nationwide, which meanwhile had also grown in size. 1 , 2 The ecological merits of resource conservation and recycling became another area of growing interest. Three emerging thermal waste-to-energy technologies seek to turn municipal solid waste from a burden to an asset. Adherents of these technologies say they produce fewer toxic emissions and virtually eliminate landfilling. But none of the technologies ... Now three new approaches to converting trash into energy—so-called waste-to-energy (WTE) technologies—look to leave mass-burn incineration behind by transforming how we think about MSW in the United States. Adherents of these emerging approaches—gasification, plasma gasification, and pyrolysis—promise cleaner emissions and more flexibility in terms of energy output, plus in some cases the virtual elimination of landfilling through a complex two-stage treatment process. 3 , 4 , 5 , 6 , 7 But none of the technologies have yet been proven on a commercial scale on U.S. soil using a typical mixed MSW feedstock, says Monica Wilson, program director for the advocacy group Global Alliance for Incinerator Alternatives (GAIA). After years of delays and high-profile failures, the technologies remain stymied by challenges such as operational inexperience, high costs, lack of financing, and concerns about toxic emissions. Furthermore, the heterogeneous nature of MSW can make it a problematic feedstock for power plants, and some critics believe it is more important to assess what materials are actually in MSW and the best uses associated with each of those materials—for instance, recycling, composting, reducing, or redesigning the materials before they enter the waste stream. Negative public perception of incineration also could prevent acceptance of newer WTE technologies in the United States. Modern mass-burn facilities are a huge improvement over the dirty plants that first drew public outrage. Beginning with the Clean Air Act in 1970, tightened regulations and sophisticated air pollution controls significantly reduced the levels of harmful chemicals emitted by incinerators. Today, 70 mass-burn plants in 21 states 8 consume about 13% of the nation’s trash, down from a peak of 14.5% in 1990. 9 , 10 Cumulatively they offer roughly 2.5 gigawatts of power in return, 11 , 12 less than a tenth of what the U.S. solar industry produces. 13 The most recent inventory available from the U.S. Environmental Protection Agency shows that MSW incinerators released about 1% of the quantity of carcinogenic and highly toxic dioxin-like compounds in 2000 that they did just 13 years earlier. 14 Yet by the 1980s the damage to incineration’s reputation was done, as far as many environmental groups and the public at large were concerned. And the battle lines drawn all those years ago remain largely intact today. So claims that these new technologies offer a panacea to waste management and a source of clean, renewable energy have met with skepticism and organized opposition in dozens of communities nationwide faced with proposals in recent years. 15 Ultimately, if the new technologies are to take hold in this country, developers must find a way to not only support their performance claims, but also demonstrate compatibility with established recycling and composting efforts and achieve financial feasibility in areas experiencing no shortage of landfill space. 16 Even some proponents of the new technologies wonder if that will ever happen.