New energy from waste capacity is eligible to generate carbon offsets based on a Clean Development Mechanism offset methodology through the Verified Carbon Standard (VCS). To date, two facilities in North America have progressed through the carbon offset generation process, successfully validating and verifying their projects in accordance with the standard. The Lee County facility began generating carbon offsets with the 2007 emissions year, and the Hillsborough County facility has verified carbon offsets beginning with the 2009 emissions year. The credits are associated with the avoidance of landfill methane and displaced grid-connected fossil fuel electricity generation. Due to extensive conservatism on the part of the CDM methodology, approximately 0.15–0.3 tons of credits are generated per ton of waste processed, depending on the specific operation generating the offsets. This is in contrast to an overall net lifecycle greenhouse gas reduction of approximately 1 ton of carbon dioxide equivalents (CO2e) per ton of waste processed relative to the business as usual practice of landfilling. More realistic methodologies could generate offset credits at a rate approaching the life cycle benefits. However, even with the current methodology, the energy from waste carbon market could exceed 800 thousand metric tonnes per year, with a value of $1.6–$3 million a year, based on current voluntary carbon offset pricing.

The role that chlorine and polyvinyl chlorine (PVC) plays in dioxin emissions from municipal solid waste (MSW) combustion has been studied and debated for 25 years. Despite energy-from-waste (EfW) facilities’ dramatic emission reductions following implementation of USEPA’s Maximum Achievable Control Technology (MACT) Guidelines, the PVC/dioxin relationship remains a source of controversy. The issue is whether removal of PVC from waste to be combusted will result in further dioxin emission reductions, as waste separation proponents allege. This paper uses the large volume of post-MACT emission testing data to describe the relationship between MSW chlorine content and dioxin emissions at operating EfW facilities and thereby determines whether PVC separation is likely to be an effective component of a dioxin emission reduction strategy. The paper also shows chlorine and PVC contents and trends in MSW, reviews dioxin formation/destruction/collection mechanisms in EfW facilities, and presents emission data as a function of EfW facility designs. The paper concludes that dioxin emissions at existing EfW facilities are insensitive to MSW chlorine content and that pre-combustion PVC removal offers no discernable emission reduction benefit.

A carbon offset program is likely to be part of any future federal cap-and-trade program and is included in both the U.S. House of Representatives passed American Clean Energy and Security Act of 2009 and the Kerry-Boxer Senate draft greenhouse gas legislation. Internationally, Energy-from-Waste (EfW) facilities in emerging economies are eligible for carbon offset credits under the Clean Development Mechanism of the Kyoto Protocol. These carbon offset credits can be purchased by developed countries, such as those in Western Europe, to help comply with their obligations under the Kyoto Protocol. Although a similar mandatory market does not yet exist in the United States, there is a growing voluntary market in carbon offsets and a set of standards designed to provide some order to this market. One of the key players in the voluntary market is the Voluntary Carbon Standard (VCS). Project types, such as EfW, that are eligible for credits under the Clean Development Mechanism are also eligible to generate voluntary carbon credits under the VCS. This paper reviews the current methodology for calculating offsets from EfW projects. The current methodology is very conservative, severely restricts the accounting for avoided landfill methane, and significantly underestimates greenhouse gas savings relative to life cycle assessments performed on waste management practices. The current methodology for offsets is compared and contrasted with a more realistic methodology more in line with life cycle assessment calculations. A review of the potential for EfW offsets under evolving state and federal programs and precedents for offsets generated based on avoided landfill methane is also completed.

This paper compares life-cycle greenhouse gas (GHG) emissions from two municipal solid waste (MSW) management options, municipal waste combustion, and landfilling, using a U.S. EPA life-cycle assessment (LCA) model, the MSW Decision Support Tool. Unlike previously reported LCAs, key combustion model inputs—total MSW carbon content and its biogenic/fossil split—are determined not from MSW composition studies, but from measurements taken at operating municipal waste combustors (MWCs). MWC measurement data show U.S. MSW carbon content averages of 30% with a biogenic/fossil split of 66%/34%. The LCA also considers a range of landfilling scenarios which account not only for alternative landfill gas (LFG) management techniques, but also for the variability of landfill methane generation and capture. The LCA found that for the range of inputs and scenarios considered, municipal waste combustion outperforms landfilling in terms of GHG emissions, regardless of the LFG management technique.

Anthropogenic sources of greenhouse gas emissions are known to contribute to global increases in greenhouse gas concentrations and are widely believed to contribute to climate change. A reference carbon dioxide concentration of 383 ppm for 2007 is projected to increase to a nominal 500 ppm in less than 50 years according to business as usual models. This concentration change is equivalent to an increase of 7 billion tonnes of carbon per year (7 Gt C year(-1)). The concept of a stabilization wedge was introduced by Pacala and Socolow (Science, 305, 968-972, 2004) to break the 7 Gt C year(- 1) into more manageable 1 Gt C year(- 1) reductions that would be achievable with current technology. A total of fifteen possible 'wedges' were identified; however, an integrated municipal solid waste (MSW) management system based on the European Union's waste management hierarchy was not evaluated as a wedge. This analysis demonstrates that if the tonnage of MSW is allocated to recycling, waste to energy and landfilling in descending order in lieu of existing 'business-as-usual' practices with each option using modern technology and best practices, the system would reduce greenhouse gas emissions by more than 1 Gt C year( -1). This integrated waste management system reduces CO(2) by displacing fossil electrical generation and avoiding manufacturing energy consumption and methane emissions from landfills.