Wednesday, November 24, 2010

Energy Recovery Council (ERC) releases 2010 Directory of Waste-to-Energy Plants

The Energy Recovery Council today released the ERC 2010 Directory of Waste-to-Energy Plants, which provides current information about the waste-to-energy sector in the United States. In 2010, 86 plants operate in 24 states and have capacity to process more than 97,000 tons of municipal solid waste per day. According to the latest BioCycle estimates, 26 million tons of trash were processed by waste-to-energy facilities in 2008. While this amount is less than the 28 million tons processed in 2006, it reflects reduced waste generation during difficult economic times rather than decreased waste-to-energy capacity.

Thursday, November 11, 2010

Techniques and timelines

A city or town can be envisioned as a thermodynamic system with a continuous input of materials and energy, generating work and wastes as output. Most material chains in today's globalized cities are open loops, starting as raw materials and ending up as wastes in landfills. They are not sustainable as the materials move in a single direction resulting in significant depletion of natural resources and causing environmental degradation over time. The creation of natural resources involves energy inputs which are embodied in the wastes that are generated at the end of material loops. Thus, closed material cycles where materials and energy are recycled or recovered hold a key to sustainable world.

Wednesday, November 3, 2010

Dioxins from WTE and coal-fired plants

QUESTION SENT TO Nickolas Themelis (NJT):

Dear Dr. Themelis,

My name is Nathan Walker and I work as an Environmental Scientist for the Shoshone-Bannock Tribes in SE Idaho. I have recently been doing research regarding waste to energy technologies for the tribes and just finished reading your 2009 Waste Management article entitle Waste-to-Energy: A review of the status and benefits in USA. I enjoyed the paper and found it informative, but was left with a nagging question that I thought you might be able to answer. The majority of the figures used to compare WTE technologies to fossil fuel energy production, especially coal, were not normalized to anything. For example, when you talk about dioxin emissions you attribute 12 g/year to WTE and 60 g/year to coal fired power plants, but fail to take into account how much coal and MSW was burned, or how many kWh were produced. If the mass/year emissions values were presented as mass/year/kWh, or mass/year/ton, or simply as a concentration of flue gas would the MSW emission values continue to hold up? I appreciate your time and look forward to your response.

Nathan Walker

Dear Nathan, there was no intention to castigate coal plants for dioxin emissions because both they and the WTE plants emit very little (by now 6 grams TEQ for WTEs and about 60 g TEG for coal fired power plants). The big dioxin emitter now according to EPA is "backyard barrel burning" (fireplaces, burning grass, etc. etc.,) amounting to about 550 grams TEQ, plus all the fireworks on the 4th of July. Even that 550 grams is insiginifant for a country the size of the U.S.