When a ton of trash is delivered to a waste-to-energy plant, several things happen: the energy content of the waste is retrieved, metals are recovered and recycled, and electricity is generated. An EPA-sponsored lifecycle analysis evaluated a variety of waste management options and their associated environmental and energy impacts, and found that waste-to-energy does the most to reduce greenhouse gas releases into the atmosphere.
The EPA’s Municipal Solid Waste Decision Support Tool has demonstrated that a modern waste-to-energy plant provides for the avoidance of greenhouse gases through three different operations:
For every megawatt of electricity generated through the combustion of solid waste, a megawatt of electricity from conventional, e.g., coal or oil-fired, power plants is avoided, creating a net savings of emissions of greenhouse gases, i.e., carbon dioxide.
A modern municipal waste-to-energy facility separates ferrous and/or nonferrous metals for recycling. This is more energy efficient than mining virgin materials for the production of new metals such as steel. As a result, there is a significant energy savings and additional avoidance of greenhouse gas emissions.
- When a ton of solid waste is delivered to a waste-to-energy facility, the methane that would have been generated if it were sent to a landfill is avoided. While some of this methane could be collected and used to generate electricity, some would not be captured and would be emitted to the atmosphere. Methane is a potent greenhouse gas twenty-three times more potent than carbon dioxide.
In addition to the analysis using EPA’s Decision Support Tool, a detailed, project analysis of a facility’s contribution to solving the threat of global warming has been completed for a 1500-ton-per-day waste-to-energy facility in the Saugus, Massachusetts. Researchers used information regarding alternative landfill disposal, plant emissions, trash composition and other plant-specific data and analyzed the information using the EPA Decision Support Tool. The study determined that about 270,000 tons of carbon dioxide equivalent emissions are avoided annually because of this one plant’s operations.
When the greenhouse gas footprint of a waste-to-energy plant is compared to the greenhouse gas releases avoided, you discover that nearly one ton of carbon dioxide equivalents are avoided for every ton of trash handled by a waste-to-energy plant. As you can see, waste-to-energy plants are tremendously valuable contributors in the fight against global warming.
The ability of waste-to-energy to prevent greenhouse gas emissions on a lifecycle basis and mitigate climate change has been recognized in the actions taken by foreign nations trying to comply with Kyoto targets. The European Union (Council Directive 1999/31/EC dated April 26, 1999) established a legally binding requirement to reduce landfilling of biodegradable waste. Recognizing the methane release from landfills, the European Union established this directive to prevent or reduce negative effects on the environment “including the greenhouse effect” from landfilling of waste, during the whole life-cycle of the landfill.
The Intergovernmental Panel on Climate Change (IPCC) has also recognized the greenhouse gas mitigation aspect of waste-to-energy. The IPCC acknowledges that “incineration reduces the mass of waste and can offset fossil-fuel use; in addition greenhouse gas emissions are avoided, except for the small contribution from fossil carbon.” This acknowledgement by the IPCC is particularly relevant due to the IPCC being an independent panel of scientific and technical experts that shared the Nobel Peace Prize with Al Gore.
The German Ministry of the Environment published a report in 2005 entitled “Waste Sector’s Contribution to Climate Protection,” which states that “the disposal paths of waste incineration plants and co-incineration display the greatest potential for reducing emissions of greenhouse gases.” The German report concluded that the use of waste combustion with energy recovery coupled with the reduction in landfilling of biodegradable waste will assist the European Union-15 to meet its obligations under the Kyoto Protocol.
Under the Kyoto Protocol, the Clean Development Mechanism (CDM) is a method of emissions trading that allows the generation of tradable credits (Certified Emission Reductions [CERs]) for greenhouse gas emissions reductions achieved in developing countries, which are then purchased by developed countries and applied toward their reduction targets. CERs are also accepted as a compliance tool in the European Union Emissions Trading Scheme.
Waste-to-energy projects can be accorded offset status under the CDM protocol (AM0025 v7) by displacing fossil fuel-fired electricity generation and eliminating methane production from landfills. An associated CDM memorandum that set out methodology for including waste-to-energy, among others, in CDM projects. The memorandum, entitled “Avoided emissions from organic waste through alternative waste treatment processes,” stated in part that CDM status could be accorded projects where “the project activity involves … incineration of fresh waste for energy generation, electricity and/or heat” where the waste “would have otherwise been disposed of in a landfill.”
The contribution of waste-to-energy to reduce greenhouse gas emissions has been embraced by The U.S. Conference of Mayors through the U.S. Mayors Climate Protection Agreement. Signed by more than 1,050 mayors, the Agreement supports a 7 percent reduction in greenhouse gases from 1990 levels by 2012 and recognizes waste-to-energy technology as a means to achieve that goal. In addition, the newly formed Global Roundtable on Climate Change (GROCC) unveiled a joint statement on February 20, 2007 identifying waste-to-energy as a means to reduce carbon dioxide emissions from the electric generating sector and methane emissions from landfills. This important recognition from the GROCC, which brought together high-level, critical stakeholders from all regions of the world, lends further support that waste-to-energy plays an important role in reducing greenhouse gas emissions. The breadth of support for the GROCC position is evidenced by those that have signed the joint statement, including Dr. James Hansen of the NASA Goddard Institute for Space Studies and David Hawkins of the Natural Resources Defense Council’s Climate Center, as well as entities as diverse as General Electric, Florida Power and Light, Covanta Energy Corporation and Environmental Defense.
Better Management of Municipal Solid Waste Will Reduce Greenhouse Gas Emissions (European Environment Agency)
Waste Sector’s Contribution to Climate Protection (German BDE [Environment Department])
Using a Carbon Balance to Estimate GHG Emissions and Mitigation from Municipal Solid Waste (Bahor, Weitz, Szurgot)
Is It Better to Burn or Bury Waste for Clean Electricity Generation (Kaplan, DeCarolis, Thorneloe)