The largest part of our business—operating WTE facilities—is recognized internationally as a source of GHG mitigation. WTE facilities avoid GHG emissions in part by combusting municipal solid waste (MSW) as a source of heat energy instead of fossil fuels. The U.S. EPA has determined that, by replacing fossil fuels, WTE facilities avoid GHG emissions at the rate of one metric ton of CO2e per ton of MSW combusted. WTE is the only major source of electricity that reduces GHG emissions. WTE facilities reduce GHG emissions by:

  • Diverting post-recycled solid waste from landfills, which emit methane, a potent GHG, for decades, even when factoring in landfill gas collection.
  • Replacing fossil fuels as a source of power generation; recovering metals for recycling, thereby avoiding GHGs associated with the production of materials from virgin inputs.

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Global WTE Net GHG Avoided


WTE Around the World

In addition to WTE, effective waste management offers several options for reducing GHG emissions. By targeting waste reduction, reuse and recycling, the amount of waste sent to landfills is reduced. Landfills are the third-largest source of methane, which is a potent GHG that is over 80 times stronger over 20 years.

Landfills are a leading source of anthropogenic methane, globally and in the United States. When biodegradable waste is placed in landfills, it breaks down anaerobically, generating methane. While today many landfills have systems in place to capture and combust this methane, either via flares or for energy recovery, it remains a highly imperfect system: landfills only capture a fraction of the gas generated. New peer-reviewed research studies are revealing much larger methane emissions than previously thought. Actual measured emissions from landfills using aircraft have averaged more than twice the amount reported in GHG inventories.

Meeting the Challenge in the Waste Sector

Transformative change to waste and materials management is among many innovative solutions the world’s economies need to meet the IPCC goal to keep global temperature rise to below 1.5°C. Examples of such changes include the following:

  • Today’s advanced WTE facilities provide opportunities to reduce GHG emissions that are not possible through landfilling.
  • Advanced sustainable waste management infrastructure, such as materials recovery facilities and anaerobic digestion, can further enhance GHG reductions.
  • The combination of carbon storage with energy sourced from sustainable biomass sources, such as the biogenic fraction of MSW, is an important component of many of the IPCC’s most recent GHG mitigation scenarios.

Accordingly, Covanta is meeting this challenge with the following:

  • Advancing recovery of aggregate materials and additional metals from ash through the start up and development of ash recycling facilities.
  • Partnering with university teams on the next generation of precious and rare earth metal recovery and upcycling of ash materials.
  • Planning tomorrow’s plants to facilitate potential inclusion of carbon capture use and storage.

In addition, we are developing a science-based target and implementation plan by 2022. Diversion of organics from landfills will play a key role, as will efforts to further reduce GHG emissions from the WTE itself across the value chain.

WTE’s Most Effective Tools in Reducing GHG Emissions

Project/GHG Reduction Goal TypeGHG Emissions Reduction as Tons CO2e
Additional energy recovery capacity0.6–1.2Per ton of MSW diverted
Recovery of metals from ash10.0Per ton of aluminum
5.2Per ton of copper
2.0Per ton of ferrous metal
Energy efficiency projects0.8Per MWh of electricity saved
Materials management1.0Per ton of MSW diverted
0.7Per ton of packaged foods diverted
Raw materials efficiency0.8Per ton of lime saved
2.6Per ton of ammonia saved

* Conservatively based on 100-yr methane global warming potential of 28 from the IPCC 5th Assessment Report. As the importance of reducing methane emissions becomes clearer, many of moving toward 20-year GWP values of over 80 to reflect methane’s short-term potency.

Our GHG Inventory

The first step in executing our GHG strategy is to understand our current emissions. Of the two major options for managing waste remaining after recycling, WTE is the only one where GHG emissions can be accurately monitored and measured. Landfills do not measure their emissions. Instead, they model them, and are allowed by U.S. EPA regulations to pick from two different approaches, which often give very different answers. We remain committed to measuring and disclosing the GHG emissions data associated with our waste management processes. Our strategy incorporates different methods, including:

  • Our larger facilities measure CO2 emissions directly through continuous emission monitors (CEMS).
  • Our smaller facilities rely on a robust emission calculation methodology that is based on the heat input to our boilers as determined by measurements of steam output. Heat input is directly proportional to the carbon content in MSW.
  • Our facilities collect samples every quarter for radiocarbon dating to ascertain the ratio of fossil to biogenic carbon.

Covanta reports its GHG emissions to the U.S. EPA GHG Reporting Program and has responded to the CDP climate change questionnaire since 2007. Our Scope 1 (direct), Scope 2 (indirect) and Scope 3 (indirect) emissions can be found in the Performance Tables.

This year, we updated our GHG inventory to reflect the 20-year Global Warming Potential of methane from the IPCC’s Fifth Assessment Report (AR5). When the convention for using the 100-year GWP was established, climate change was viewed as a longer-term problem. Today, we now know that climate change tipping points are much closer than we initially thought. As a result, both policymakers and scientists are calling for a more urgent need to address short-lived climate pollutants, like methane. Using the 20-year GWP better focuses efforts on the short term. Most recently, NY State included the 20-year GWP for methane in the Climate Leadership and Community Protection Act (CLCPA). Additionally, disclosure and ranking companies such as CDP have made the AR5 20-year GWP available to companies for reporting. The CDP’s guidance recommends using the GWPs from the most recent IPCC Assessment Report. It is becoming increasingly clear to policy makers that, in order to reach short-term GHG goals, we cannot overlook the potency of methane or the benefits of avoiding it.

For more information, please see our most recent CDP responses, covering emissions from 2016 through 2020:

WTE and GHG-Limiting Programs

Although WTE is widely recognized as a source of GHG mitigation, our combustion process results in facility-level GHG emissions that could be subject to cap-and-trade or other laws or regulations designed to limit or reduce GHG emissions. We continue to advocate for consistent treatment of GHG emissions from the waste management sector to ensure that economic signals (e.g., allowance purchase requirements, carbon taxes) align with the relative life-cycle GHG emissions of different waste management options.

In 2020, 2.3% of our total equity-share GHG emissions were subject to a cap-and-trade program. The status of Covanta’s WTE operations in current emissions-limiting programs is as follows:

  • The European Union Emissions Trading Scheme (EU-ETS), the largest and longest running carbon cap-and-trade program, currently excludes WTE from the cap. However, the benefits of WTE are recognized though the concurrent inclusion of WTE in renewable energy programs and the implementation of the landfill directive, which calls for a minimum of 65% of biodegradable waste to be diverted from landfills to alternatives, including recycling, composting, anaerobic digestion and WTE.
  • California’s Global Warming Solutions Act of 2006 (AB 32) seeks to reduce GHG emissions in California to 1990 levels by 2020, through an economy-wide cap-and-trade program. As part of the program, WTE facilities are granted a provision for free allowances that reduce the compliance burden.
  • The Regional Greenhouse Gas Initiative (RGGI) is an operating regional cap-and-trade program in the Northeastern United States focused on fossil fuel-fired electric generators; it does include WTE facilities. We operate one natural gas-fired boiler at our Niagara facility that is included in the RGGI program.
  • WTE is recognized as a source of credits under the United Nations’ Clean Development Mechanism (CDM), where more than 40 million projects have been registered with a combined annual GHG reduction of 5 million metric tons of CO2e a year.