There’s no denying it: People produce a lot of trash. In fact, the world has more waste now that it ever has in the history of humankind. In the United States alone, we produce almost 300 million tons of trash every year. And that number is rising as our population continues to grow, according to the latest research from experts.
In fact, there is so much trash across the planet that it has actually created an eighth continent — the Great Pacific Garbage Patch. This human-made mass, which floats between California and Hawaii, is three times the size of France and is comprised of 1.8 billion plastic pieces.
Clearly, trashing the planet has reached a critical point and we need a more sustainable, eco-friendly, and cost-effective way to manage it all. One such way to address the problem is “waste-to-energy,” or WTE for short, which approaches energy production a bit differently from traditional fossil fuels or renewable energy systems.
Proponents assert that waste-to-energy plants reduce greenhouse gas emissions, boost our energy efficiency, and lower the amount of waste that ends up in landfills or in the ocean. But is burning trash really the answer to our environmental woes? Let’s take a closer look at waste-to-energy practices, how WTE plants operate, and some of the pros and cons of using trash as a means to generate power.
What Does Waste-to-Energy Mean?
As its name implies, waste-to-energy refers to the process of converting waste (called municipal solid waste or MSW) into energy. In the United States, there are three methods of solid waste management:
- Treatment and disposal, mostly via landfills (52.5%)
- Recycling and composting (34.7%)
- Waste-to-energy (12.8%)
Cities use labyrinthine sewer systems for solid waste management, landfills act as permanent storage facilities for organic waste, and hazardous waste management systems exist for dealing with especially toxic substances.
But despite its name, waste isn’t always just waste. It can be used in energy production, be it electricity for a home or industrial building. In the next few sections, we’ll discuss the different ways in which waste-to-energy facilities can be used to simultaneously lighten the burden of waste management while also serving as valuable supplements to our existing energy system in a potentially more sustainable way.
What Do They Do at Waste-to-Energy Plants?
Human ingenuity is as operative in waste management as it is anywhere else. Long ago, it occurred to enterprising thinkers that it might be possible to treat waste less like waste and more like a potential source of energy. Today, there are several kinds of waste-to-energy practices — incineration, gasification, and pyrolysis.
Incineration of Municipal Solid Waste
You might think incineration is just a fancy word for “burning,” but it refers specifically to burning potentially dangerous substances at high enough temperatures to destroy most contaminants. Though simple burning can take place almost anywhere, incineration requires a special furnace called an incinerator.
The combustion of municipal solid waste is a form of waste incineration. It’s fairly straightforward: rather than sending organic waste to a landfill for all eternity, it can be burned. This produces steam, which can be used to turn a turbine to generate electricity.
Once the trash arrives at the waste-to-energy facility, it’s processed in machines that transport it into incinerators where it’s burned at high temperatures. The released heat then produces steam, which powers a turbine, and the turbine produces electricity.
It’s worth noting that this method can create a fair bit of air pollution, including fine particulates, dioxins, ash, and flue gas. While many facilities tout that they are precisely engineered with pollution control in mind to keep residues at a minimal level, there is plenty of backlash, including as it pertains to environmental justice.
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Gasification and Pyrolysis
Another way to convert waste materials into energy is the process of gasification, in which feedstock like waste or coal is turned into synthesis gas (syngas) in a high-temperature gasifier. This syngas can be enriched with hydrogen and converted into diesel fuel or gasoline.
A related but distinct procedure is called pyrolysis, which involves burning a solid or liquid in a range of temperatures in the absence of oxygen. When plastics are put through pyrolysis, for example, oil is created as a byproduct. Whether it’s syngas or oil, the end result is a usable fuel resulting from what had been a waste product.
Do Landfills Produce Energy?
Even if waste does end up in a landfill, there are still ways it can contribute to the energy system. Though landfills are dotted with washing machines, old clothing, and pots and pans, quite a lot of what’s stored there is biomass.
Biomass is organic material that is produced by plants and animals. It can include manure, wood products, crops, and crop waste materials. When biomass goes through anaerobic digestion (that is, when bacteria breaks down organic matter), the result is an energy-dense byproduct called biogas that can be burned for energy.
When refined, biogas can even be turned into renewable natural gas, a form of gaseous energy pure enough to be substituted for standard natural gas. This means it can be used in many applications where natural gas would provide power, such as fueling certain kinds of vehicles.
Is Waste-to-Energy Effective?
Waste-to-energy refers to a family of approaches for turning waste products—including biomass, organic waste, and even plastics—into energy. This can be accomplished in numerous ways, including incineration, pyrolysis, and gasification.
Whether or not it’s effective depends upon what you’re trying to accomplish. Though it’s unlikely that waste-to-energy is soon going to power the whole world, it is one way of moving towards a circular economy (an approach to production that minimizes and reuses waste) by producing valuable energy from what is essentially trash.
Is Waste-to-Energy Sustainable?
In conversations about the environment, sustainability refers to any process that can be carried forward into the future indefinitely. Some assert that WTE is a sustainable option because there’s unlikely to ever be a serious shortage of waste. In fact, some states consider WTE plants to be renewable energy facilities that reduce methane and greenhouse gas emissions.
What Are Some of the Drawbacks of Waste-to-Energy?
Waste-to-energy has both benefits and drawbacks. It produces energy, an essential commodity for everyday life, and it does so using waste, which reduces the amount of trash that might otherwise end up in a landfill or the ocean.
That said, waste-to-energy does have certain negative environmental impacts. For instance, WTE plants that utilize incineration create fine particulates and release harmful pollutants in the air, such as lead and mercury, that affect both the environment and people. In particular, research shows that WTE plants are often found in low-income neighborhoods spanning from Detroit to the suburbs of California and Florida.
The same concerns also come up when discussing pyrolysis, which creates both carbon monoxide and carbon dioxide. It also creates biochar, an ashy substance similar to charcoal. By weight, biochar is about 70% carbon, which can stored or used as a fertilizer.
What Are the Benefits of Waste-to-Energy?
WTE is an approach to waste treatment that both directly produces energy for lighting homes and running industry while also directly reducing waste. Waste-to-energy helps to reduce the use of landfills and puts waste to use in energy production.
According to the California Department of Resources Recycling and Recovery, “Anaerobic decomposition of organic materials in landfills produces methane (CH4), a greenhouse gas with global warming potential approximately 85 times higher than carbon dioxide (CO2) over a 20-year time period.”
As such, burning trash instead of fossil fuels like coal and natural gas is more eco-friendly. This is an enormous benefit, especially considering the World Bank Report’s prediction that there will be a 70% increase in the amount of global waste production by the year 2050.
For all its benefits, waste-to-energy presents some problems. For one thing, it’s a relatively small source of energy, accounting for just 14% of renewable energy production in the U.S. We won’t soon be replacing fossil fuels with biogas from landfills. That said, it’s worth making every effort to increase our energy efficiency while reducing waste.
Also, waste-to-energy is not a perfectly clean, efficient process. Technology has been developed to substantially reduce the contaminants that result from waste-to-energy production methods. Modern furnaces, for example, use oxygen enrichment, waste pre-treatment, and advanced, high-efficiency combustion systems to reduce particulate waste.
What’s the Difference Between Waste-to-Energy and Recycling?
Though there are obvious surface similarities, waste-to-energy processes are not the same thing as recycling.
Recycling refers to taking waste products, like plastic bottles and cardboard boxes, and pre-sorting them into different categories, then converting them directly back into new products for consumption.
Waste-to-energy, on the other hand, refers to any of a family of techniques for taking waste products and converting them directly into energy through a process like incineration or anaerobic digestion.
If you’re taking used plastic and turning it into new plastic, that’s recycling. If you’re taking used plastic and burning it for fuel, that’s waste-to-energy.
Learn More About Waste-to-Energy
It’s well-established that fossil fuels produce greenhouse gas emissions, with methane being especially problematic. The hope is that cost-effective energy technologies will continue to power our growing populations without worsening climate change.
While renewable energy options like nuclear power, hydro power, solar power plants continue to gain attention, waste-to-energy cannot be ignored. It’s likely not the panacea for all our environmental problems, but it’s certainly worth learning about. To be part of the solution, discover some easy ways to become more energy efficient at home and how to make a difference for your family with clean energy.
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