Waste incinerators do not eliminate waste – in fact they generate it. Since physical matter cannot be destroyed, an incinerator actually transforms the original wasted materials (or resources) into several new forms of waste: air emissions, ash, and liquid discharge (resulting from cleaning processes within the incinerator). Incinerators reduce solid waste to approximately 10-15% of the original volume and 20-35% of the original weight, which exits the incinerator in the form of fly ash and bottom ash. These new forms are far more difficult to deal with than the original, raw wasted materials.
Alone, among waste management options, incineration knowingly creates hazardous waste where none existed in the feedstock (municipal solid waste).
Incineration has many downsides, including significant negative impacts on human health (cancer, birth defects and breathing problems), carbon emissions, low employment, large capital investment with low return and an ongoing landfill requirement for the remaining waste left over from incineration. Mixed-waste incinerators are inefficient energy producers, capturing only about 20% of energy generated by the waste.
Waste-to-energy proponents make claims about their energy production potential and consequent reduced use of fossil fuels without addressing a far more important issue: the huge loss of resources and energy already used to produce the material being burnt.
What is incineration?
Incineration refers to the combustion of waste materials, resulting in ash residues and air emissions. Gasification, pyrolysis, and vitrification are variations of incineration, and waste-to-energy refers to an incinerator that incorporates technology to generate power from the heat produced during the combustion process.
Read more about about so-called “advance recycling” and “chemical recycling” including waste-to-fuels, plastic-to-fuels.
The facts:
Incinerators destroy valuable resources
Incinerators destroy valuable, non-renewable resources, most of which are fossil-fuel based plastics. Several studies have shown that overseas waste-to-energy incinerators burn mostly recyclable or compostable waste. In Aotearoa NZ, council analyses of the average household rubbish bag repeatedly reveal that most of what we throw out is recyclable or compostable.
Everyone, everywhere is looking for ways to reduce, reuse, repair, refurbish and recycle the things we use so we can conserve resources and keep materials in use for as long as possible. Incineration works directly against these efforts.
Large-scale waste-to-energy incinerators for municipal solid waste are expensive to set up and require a return on investment - a long-term proposition. Once built, most large-scale modern incinerators require a consistent inflow of about 100,000 tonnes of municipal solid waste a year. Councils sign long-term contracts requiring them to deliver a minimum quantity of waste for 20 to 30 years. If they do not meet the minimum, they must pay fees to compensate the incinerator company for lost profits.
Incinerators also destroy human resources
Incinerators destroy good jobs. A key selling point used by incinerator companies is that they create jobs. The EU social enterprise reuse, repair and recycling group, RREUSE, recently looked into that and found that for every job an incinerator creates, recycling centres create 36 jobs, and reuse activities create 296 jobs. Waste and recycling services are set to become the fastest growing sector as our country moves towards a circular economy. Incineration is not part of this shift.
Incinerators contribute to climate change
Most of the gas coming from an incinerator is carbon dioxide. That is because most of the rubbish going into an incinerator is carbon-intensive plastic. Plastic is made of fossil fuels and burning it, rather than burying it in landfill, produces high levels of greenhouse gases.
In September 2024, the BBC published a report examining five years of data from across the UK, and found that burning waste produces the same amount of greenhouse gases for each unit of energy as coal power, which was abandoned by the UK.
The Intergovernmental Panel on Climate Change reports that each tonne of waste burnt produces up to 1.2 tonnes of carbon dioxide. As I’m sure you know, we’re looking for ways to urgently reduce our climate change emissions. Waste-to-energy incinerators work in direct competition with this goal.
The evidence suggests that the carbon intensity of energy produced through incineration is around 2 times greater than the carbon intensity of the average electricity grid intensity in the European Union and has significantly more adverse climate impacts than conventional electricity generation from fossil fuels such as gas. Meaning it is better and cleaner to just burn the fossil fuels directly for “energy” because incinerators are so inefficient and polluting.
Since these infrastructures are meant to last for about 20-30 years, they are delaying a much needed and urgent transition to less carbon intensive power generation infrastructure such as wind and solar renewable energy. It would be environmentally irresponsible to continue to promote waste to energy infrastructures that are already largely outperformed by the EU average and even worse, by conventional fossil fuel energy generation such as gas.
Incinerators pollute our air, land and water
Toxins that come out of incinerators include dioxins, mercury and cadmium that can cause cancer, nerve damage and birth defects. Anyone who lives downwind from an incinerator is in danger of breathing in these dangerous chemicals. Toxins also fall on the land to be eaten by livestock or washed into our rivers, harbours and coastal waters where they can enter our food chain.
Pollutants that escape smokestack accumulate over time. Both dioxins and heavy metals like mercury have toxic effects and are especially dangerous to unborn children. When they are ingested by animals, they contaminate dairy and meat. They can also wash off the land into our waterways where they pollute the fresh and marine water species. These toxins can then enter our bodies when we eat contaminated kai moana and kai awa. Meanwhile, toxins, heavy metals and other persistent organic pollutants (POP) are not destroyed during the incineration process. Those that are not captured in filters, are released to pollute the air. This is called ‘fly ash” which is classified as hazardous waste.
The rest ends up in ash, slag and contaminated wastewater: very large quantities of it. The ash from the incinerator fire box is known as “incinerator bottom ash” or “IBA” Numerous studies have shown that heavy metals can be released from IBA and be washed into the surrounding environment (see footnotes 5,17-19 in linked study). This poses a particular threat because heavy metals are highly toxic even at low concentrations. In Aotearoa NZ, the national dioxin inventory shows clearly that landfills are the largest source of dioxin, but landfills don’t create dioxin - the dioxin is simply that which went into the landfill and leaked out. Incinerators, by contrast, create dioxin by incomplete combustion. The ash that results contains high levels of dioxin, ensuring that the dioxins going into our landfills will significantly increase, and ultimately leak out into the environment to pollute our land and waterways.
Incinerators are dangerous to human health
Waste incineration poses a significant threat to public health and the environment. The major impact on health is the higher incidence of cancer and respiratory disease; other potential effects are congenital abnormalities, and hormonal defects. The contribution of incineration to climate change also has specific health implications.
Incinerators release particulates to that air that are the most dangerous for human health (PM2.5). In addition, recent evidence suggests that particles containing heavy metals and ultra-fine particles (UFP), such as those emitted from incinerators are especially of concern with regard to health.
Incinerators release a wide variety of pollutants depending on the composition of the waste. The significant pollutants emitted are particulate matter, dioxins and furans, heavy metals like mercury, lead and arsenic, persistent organic pollutants (POPs), acid gases, oxides of nitrogen, and sulfur, aside from the release of innumerable substances of unknown toxicity.
Carbon dioxide (CO2) is the largest emission from incinerators. It is responsible for climate change, which is in turn responsible for increasingly frequent extreme weather events, such as heatwaves, storms and floods, the disruption of food systems, increases in food-, water- and vector-borne diseases, and mental health issues.
Furthermore, climate change is undermining many of the social determinants for good health, such as livelihoods, equality and access to health care and social support structures. These climate-sensitive health risks are disproportionately felt by the most vulnerable and disadvantaged, including women, children, ethnic minorities, poor communities, migrants or displaced persons, older populations, and those with underlying health conditions.