Originally Posted by Michael

Where is the down side to this? We have to dispose of waste, so why not do it in a manner that generates energy? M

Wednesday, July 02, 2008

Garbage In, Megawatts Out
Ottawa will build the first gasification facility in North America to make energy from waste.

By Peter Fairley



This week, city counselors in Ottawa, Ontario, unanimously approved a new waste-to-energy facility that will turn 400 metric tons of garbage per day into 21 megawatts of net electricity--enough to power about 19,000 homes. Rather than burning trash to generate heat, as with an incinerator, the facility proposed by Ottawa-based PlascoEnergy Group employs electric-plasma torches to gasify the municipal waste and enlist the gas to generate electricity.

A few waste-to-energy gasification plants have been built in Europe and Asia, where landfilling is more difficult and energy has historically been more costly. But PlascoEnergy's plant would be the first large facility of its kind in North America. The company's profitability hinges on its ability to use a cooler gasification process to lower costs, as well as on rising energy and tipping fees to ensure strong revenues.

PlascoEnergy's approval marked the latest in a string of positive developments for waste gasification projects in recent weeks. Last month, Hawaii okayed $100 million in bonds to finance a waste-to-energy plant using plasma-torch technology from Westinghouse Plasma, based in Madison, PA, that is already employed in two large Japanese waste processing plants. Meanwhile, Boston-based competitor Ze-gen reported the successful ramp-up of a 10-metric-ton-per-day pilot plant in New Bedford, MA, that uses molten iron to break down waste.

Most gasification plants work by subjecting waste to extreme heat in the absence of oxygen. Under these conditions, the waste breaks down to yield a blend of hydrogen and carbon monoxide called syngas that can be burned in turbines and engines. What has held back the technology in North America is high operating costs. Plasma plants, using powerful electrical currents to produce a superhot plasma that catalyzes waste breakdown, tend to consume most of the energy they generate. As a result, the focus of plasma gasification plants has been to simply destroy hazardous wastes. "There was really no thought of being able to produce net power," says PlascoEnergy CEO Rod Bryden.

PlascoEnergy started looking at gasification for municipal solid waste five years ago, when it determined through simulation that cooler plasma torches could do the job. "The amount of heat required to separate gases from solids was much less than the amount being delivered when the purpose was simply to destroy the material," says Bryden. PlascoEnergy tested the models on its five-metric-ton-per-day pilot plant in Castellgali, Spain (jointly operated with Hera Holdings, Spain's second largest waste handler). In January, the company began large-scale trials in a 100-metric-ton-per-day demonstration plant built in partnership with the city of Ottawa.


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Technology Review: Garbage In, Megawatts Out