Recover and Generate EnergyResource
Dry Organic Waste:
- Wood Residuals
- Yard Waste
- Non-Recyclable Paper
- Construction and Demolition Waste
When is it Waste?
After initial use.
Conventional Approach
Collect and landfill.
Regenerative Approach
Collect and divert to composting or to energy production through combustion.
Considerations for Implementation
Communities with wood residues which are not suitable for other uses could consider including this source with dry organic waste from the community (e.g. paper and cardboard products which cannot be recycled) as feed stock for a gasification and cogeneration plant. If the plant could be located on an existing industrial site, then capital and operating costs could be reduced by sharing operating and maintenance personnel.
This strategy is particularly well suited to a public-private partnership with an industry partner that produces a large amount of wood waste.
Environmental Benefits
Diversion of organic waste from landfill, resulting in: reduced greenhouse gas emissions, reduced leachate & reduced need for land for landfill expansion Diversion of dry organic waste from conventional mass burn incineration Reduced air pollution Production GHG-neutral fuel that can offset fossil fuels and be used in cogeneration plants to produce electricity Production of cleaner ash that can be added to composting feed stocksSocial Benefits
Reduced pollutants and air particulars compared to conventional mass burn of wood residues
Revenues that stay within the community
Local job creation
Economic Benefits
Reduced overall lifestyle cost of infrastructure
New revenue source from sale of biofuel, tipping fees, and greenhouse gas credits
Combustion of Wood Waste
How It Works
When mixed with wet organic waste, dry organic waste can be composted, however the low moisture content makes it difficult for microorganisms to digest the material through biological treatment. Instead, dry organic waste is suitable for thermal treatment.
Wood residuals, such as waste from sawmills, is burned as a fuel to produce heat. The heat can be delivered to nearby users through a district energy system.
Where is it Happening?
Prince George Downtown District Energy System
Waste to Energy
How It Works
Incineration of municipal solid waste in conventional mass burn systems is an old waste management practice that alone is not an integrated resource recovery approach; However, there are methods of generating energy from combustion of municipal solid waste that use newer technologies to recover some energy and better manage air pollution.
In some Waste to Energy combustion facilities, sorted dry waste such as non-recyclable paper, cardboard, plastics, textiles and wood residues combust to generate heat and electricity.
But First
Reduce solid waste through diversion programs first and apply the principle of highest and best use.
Waste-to-Energy facilities should be built to an appropriate scale, sited beside a customer that could benefit from the energy generated, and accept diverse waste streams to ensure viability.
Where is it Happening?
The Burnaby Waste-to-Energy facility, operating as Covanta Burnaby Renewable Energy, converts post-recycled solid waste and other materials to steam and electricity through cogeneration.
Gasification
How It Works
During gasification, the waste is heated in a vessel with limited amounts of oxygen. The waste decomposes to ash and "synthesis gas" (“syngas” for short), a mixture of hydrogen, carbon monoxide, carbon dioxide, methane, and more complex hydrocarbons. Synthesis gas can be burned in a boiler for heat, or in a cogeneration plant to produce heat and electricity. It is not suitable for transmission through natural gas networks. Synthesis gas can also be reformed into liquid fuel and blended with gasoline for use in fleet vehicles.
Gasification is a cleaner process than traditional incineration, since the process can be more tightly controlled and since it presents two opportunities for removing contaminants: first from the synthesis gas stream between the gasifier and the cogeneration engine or boiler, and again from the exhaust stream from the cogeneration engine or boiler to heat or electricity.
What are the Costs?
Economic viability of gasification plants depends on their size, the composition of source waste stream, whether it receives tipping fees, whether the produced energy can be sold via cogeneration of electricity and heat, and whether greenhouse gas credits are sold. Gasification plants require less land than biogas plants.
Where is it Happening?
Kwadacha First Nation Off-grid Utility Standard Biomass Gasification-to-Electricity Project
