Long considered a costly problem, municipal solid waste is now emerging as an important revenue-generating feedstock for waste-to-energy systems.
As municipalities look to improve energy efficiency and reduce greenhouse gas emissions as part of their sustainability planning initiatives, new and innovative methods for burning wastes to generate heat and power are emerging.
And while, at first glance, disposing of municipal wastes would not appear to lend itself to high tech solutions, technologies that convert waste materials such as paper and plastics to produce synthetic gas (syngas) that, in turn, can be burned to generate energy are changing the economics of waste management.
What's more, technologies that reduce the volume of solid wastes in landfills have environmental benefits worthy of consideration.
Even though improved technologies have largely eliminated such risks, opponents of waste-to-energy systems resist any form of wastes incineration near homes and businesses for fear that fine particulates, heavy metals, trace dioxins, acid gas emissions, toxic fly ash, or incinerator bottom ash might escape into the atmosphere or pollute sensitive urban eco-systems.
Modern direct incineration plants must meet strict emission standards in most countries and thus are vastly different from older systems that in some cases did not recover energy or materials. These new systems can reduce the volume of original waste by 95-96 %, depending on what is being burned and what is recovered, such as metals from the ash for recycling.
But there is a wide variety of new technologies entering the marketplace that are replacing direct waste incineration as a means to generate energy. These include:
- Gasification - which produces combustible gas, hydrogen, and synthetic fuels;
- Thermal depolymerization - w hich produces synthetic crude oil that can be further refined;
- Pyrolysis - which produces combustible tar or bio-oils; and
- Plasma arc gasification or plasma gasification - which produces rich syngas including hydrogen and carbon monoxide usable for fuel cells or generating electricity.
Municipal authorities are increasingly viewing such waste-to-energy conversion systems as potentially profitable alternatives to direct incineration or the use of landfills.
And while the public sector has traditionally dominated the waste management industry, rising oil prices, and ever-increasing demand for energy are attracting private sector investment into the market, now estimated to reach $28.8 Billion by 2015. (See GLOBE-Net article 'Global Waste-to-Energy Market to Reach $28.8 Billion by 2015.'
While Europe dominates the highly competitive world waste-to-energy market, key players can be found on all continents. Leading companies include AE&E Group GmbH, Axpo Kompogas AG, Babcock & Wilcox Volund A/S, Bedminster International Ltd., BiogenGreenfinch, BTA International GmbH, Community Power Corporation, CNIM, Covanta Holding Corporation, EcoCorp Inc., Keppel Integrated Engineering Ltd., North American Power Group Ltd., Organic Waste Systems NV, STRABAG Umweltanlagen GmbH, Veolia Environmental Services, Waste Management Inc., and Wheelabrator Technologies Inc., among others.
Covanta Holding Corporation operates 44 Energy-from-Waste facilities for communities worldwide that collectively process 20 million tons of waste per year, recycle over 400,000 tons of metals, and generate nine million megawatt hours of electricity.
A Covanta subsidiary, Covanta Burnaby Renewable Energy, Inc., operates a waste-to-energy facility responsible for the environmentally safe disposal of over 25 % of the Metro Vancouver region's waste. Each year it turns 285,000 tonnes of garbage into steam and electricity. The plant is one of the cleanest WTE facilities of its kind on the continent.
Veolia ES Waste-to-Energy, one of four business units of Veolia ES North America, operates waste-to-energy plants under long-term, fixed-price contracts with performance guarantees in communities throughout North America. Veolia has several facilities in Quebec and is looking to expand elsewhere in Canada.
North American Power Group Ltd. operates several facilities in California, recyclingurban and agricultural wood waste into energy sold under contract to Pacific Gas & Electric Company through to 2020.
Other companies with innovative technologies hold promise for urban-based energy plants using other waste streams.
Ottawa-based Plasco Energy Group employs a patented process using plasma arc technology for the conversion of waste material into synthetic gas and marketable products. Plasco recycles heat from the process to gasify the waste and then uses the plasma to refine the gaseous products into a clean, consistent syngas
Vancouver-based Nexterra Energy Systems' proprietary gasification technology provides a clean, versatile, and low-cost means of converting wood and other solid fuels into syngas to produce heat and power at plant-scale applications.
The company initially developed gasification systems to displace natural gas at sawmills, panel board plants, pulp and paper mills, and institutional facilities using wood fuel.
Nexterra's technology has been deployed at several universities in Canada and the United States and is being used to generate heat at Dockside Green, the 1.3 million-square- foot residential and commercial development in Victoria's Inner Harbour.
At GLOBE 2012, taking place on March 14-16, 2012 in Vancouver, leading world city planners, technology developers, and energy experts will be on hand to address issues around access to waste-to-energy feed stocks, emissions, and particulate matter management, and public health and safety concerns in order to help determine the place for these technologies in the cities of tomorrow.