Introduction: Addressing the Global Waste Crisis

Waste-to-energy facilities offer significant environmental protection, reduce greenhouse gas emissions, and play an important complementary role in recycling efforts, according to a new City College of New York Grove School of Engineering report that reviews the most up-to-date scientific studies of the industry.
The report, “The Scientific Truth about Waste-to-Energy” by City College chemical engineer Marco J. Castaldi, calls upon dozens of independent scientific reviews to offer a comprehensive assessment of waste-to-energy’s influence on environmental sustainability and public health. The report was peer-reviewed by subject matter experts at Columbia University, University of Maryland, North Carolina State University, State University of New York- Stony Brook, and several international and U.S.-based energy and resource management officials.

The report can be used to address outdated data and unscientific conclusions that have fueled debate around the safety and benefits of waste-to-energy. By analyzing the findings of a wide range of independent research studies conducted around the globe, the report serves as an in-depth guide for policy makers and municipalities evaluating the scientific merits of waste-to-energy and its appropriate role in sustainable waste management initiatives.
“In recent years, it has become evident that local policy makers struggling to manage daunting waste management challenges are doing so with outdated or erroneous information,” Castaldi said. “This report is an effort to provide officials with a single source of reliable information that draws its conclusions from a wide range of research and has undergone rigorous vetting by subject matter experts from diverse backgrounds and organizations. My hope is that, moving forward, officials will be well positioned to make policy decisions based on established facts rather than unsubstantiated claims.”

The world currently has more trash than at any point in history – with the U.S. generating nearly 300 million tons a year, according to the most recent EPA figures.  Waste-to-energy facilities generate renewable energy from non-recyclable and non-compostable waste that would otherwise be landfilled. Castaldi’s report notes the amount of waste to be landfilled can be reduced up to 90% when employing waste-to-energy.

What is Waste-to-Energy?

WtE encompasses a range of technologies that convert non-recyclable waste into usable energy, including:

• Thermal treatment (incineration with energy recovery)
• Gasification and pyrolysis
• Anaerobic digestion for organic waste

These technologies enable the recovery of electricity, heat, and secondary materials, aligning with circular economy principles .

Climate Impact: A Key Tool for Greenhouse Gas Reduction

Scientific consensus confirms that WtE plays a critical role in reducing greenhouse gas emissions:

• Landfills emit methane through anaerobic decomposition
• WtE avoids these emissions by diverting waste from landfills
• Each ton of waste processed can avoid approximately one ton of CO₂-equivalent emissions

Additionally, WtE generates energy that displaces fossil fuel-based power, further contributing to decarbonization.

Complementarity with Recycling

Contrary to common misconceptions, WtE does not compete with recycling—it complements it. Evidence shows that regions with WtE infrastructure often achieve higher recycling rates, as systems are designed to:

• Prioritize material recovery
• Treat only non-recyclable residual waste
• Recover metals from incineration residues

This integrated approach optimizes resource efficiency across the waste hierarchy.

Environmental and Health Considerations

One of the most debated aspects of WtE is its impact on public health and the environment. However, decades of peer-reviewed studies demonstrate that:

• Emissions from modern WtE plants are well below regulatory limits
• Advanced flue gas cleaning systems capture pollutants such as dioxins, particulates, and heavy metals
• Epidemiological studies show no significant adverse health effects for populations living near properly operated facilities

In fact, compared to uncontrolled landfilling or open burning, WtE provides a controlled and environmentally sound alternative.

Contribution to the Circular Economy

WtE facilities are not merely disposal plants—they are resource recovery hubs:

• Metals are recovered and recycled from bottom ash
• Energy is produced for electricity grids and district heating
• Residual materials can be reused in construction applications

This aligns with global sustainability goals and supports efficient resource utilization.

Strategic Role in Global Waste Management

WtE is particularly critical for:

• Densely populated urban areas with limited landfill space
• Developing economies facing rapid waste growth
• Regions seeking to reduce methane emissions under climate commitments

As part of an integrated system—including reduction, reuse, recycling, and recovery—WtE provides a reliable and scalable solution.

Conclusion: Science over Perception

The scientific evidence is clear: Waste-to-Energy is a safe, efficient, and climate-beneficial technology when properly implemented.
Policy decisions should be guided by data-driven analysis and peer-reviewed research, rather than misconceptions. WtE is not a standalone solution, but a critical pillar of sustainable waste management, enabling societies to transition toward a low-carbon and circular economy.