Not Your Granddaddy's Garbage Burners: Why Burning Waste for Energy Fights Climate Change
The technology is cleaner and safer than generally believed
By Shawn Lawrence Otto | Jun 06, 2013 | Comments (2)
When we think of climate change deniers, tea partiers and republicans often come to mind. But some of the most troubling stumbling blocks to reducing greenhouse gases come from urban liberals and left-leaning environmental groups who oppose burning municipal solid waste to produce energy.
In California, when new Waste To Energy plants (WTEs) are proposed, they run into buzz saws of liberal opposition. Consequently, California leads the nation in landfilling, at 28 million tons. Plans to increase the volume of waste burned at a Minneapolis WTE facility have been blocked for four years, and the issue recently divided the Democratic candidates for mayor. So they landfill the extra instead. From New York to Massachusetts to Rhode Island to Pennsylvania to Maine, opposition has delayed or stopped WTE plants across the nation, largely in liberal-controlled urban areas.
But the opposition is misguided. Today's Waste To Energy plants (WTEs) are not your granddaddy's trash burners, and some liberal groups, like the Center for American Progress, are starting to look at the actual science and reevaluate long-held assumptions in light of new information and increasing concern over climate change. When they do, they are finding that today's Waste To Energy plants look surprisingly good for the environment and for fighting climate change.
How Waste To Energy Plants Work
Source: Covanta Energy, one of the two major US WTE operators.
Reduce, reuse, recycle—and then what?
Americans generate about 390 million tons of trash every year—as much as 7 pounds per day for every man, woman and child. The problem ranks with energy, food, population and the economy as one of the biggest issues humans need to tackle to create a sustainable world. The US recycles and composts about 94 million tons of that waste, or roughly 24%, but could do much, much more.
Even if the US doubled its rate of recycling, there would still be hundreds of millions of tons of post-recycled, post composted solid waste. What you do with it is the question, and there are two options: dump it in a landfill or burn it/gasify it for energy.
Liberals, overwhelmingly, are choosing to dump, which science shows is the most polluting alternative. Because of liberal opposition, almost no WTEs have been built in the United States for twenty years, despite the science-based classification of WTE as clean or renewable energy by the EPA and 31 state environmental agencies.
Things are very different in green-conscious Europe. While the US has just 89 WTE facilities, Europe has 420 and is building more. Northern Europe, the most environmentally-conscious part of the continent, is also where the most WTEs are located.
WTE construction in the US is being held back by fears that burning trash will cause people to reduce their recycling effort or will put dangerous toxins into the environment. But are those fears supported by the evidence?
Evidence shows recycling and WTE are complimentary
It is certainly true that maximum recycling effort should be put in to remove all recyclables and compostables before the remaining waste is disposed of in a landfill or a WTE facility. But the worry that WTEs reduce recycling rates does not appear to be borne out by the evidence, which shows that to the contrary, they tend to be associated with increased recycling effort.
The five European nations with the highest recycling rates—Germany, the Netherlands, Austria, Belgium, and Sweden—also have among the highest WTE usage, to the point that they have reduced landfill use to less than one percent of their waste. Sweden even competes to import waste. While this is questionably desirable, it does not appear to have reduced their recycling effort, which is higher than the twenty two other European nations.
In America, by contrast, where environmental groups frequently portray the issue as an either/or choice between recycling and WTEs, both rates are much lower, and a whopping 69 percent of US municipal solid waste winds up in landfills.
As in Europe, the trend of increased recycling rates in communities that use WTE also holds in the US, where communities that have a WTE plant show higher recycling rates than the national average.
Finally, recycling itself is not without waste. For example, recycling mixed paper leaves a 15 percent residue that itself has to be disposed of somehow.
Clearly, recycling and WTE can and do go hand-in-hand in a responsible waste management plan, and co-promotion by environmental groups would likely increase both WTE and recycling, both of which are preferable to landfilling in the waste management hierarchy.
Clean air technology cuts emissions to near-zero
While trash burners once did put dangerous toxins into the air, in the last ten years WTE pollution control technology has become so advanced that the most common and dangerous toxins have been almost completely eliminated, something that the environmental groups who still oppose WTEs rarely mention.
Under the Clean Air Act, WTE facilities are required to be equipped with the most modern air pollution control technology available to ensure that smokestack emissions are safe for human health and the environment. This new equipment must meet or exceed the EPA’s Maximum Achievable Control Technology (MACT) Standards. WTE plant emissions are far below the limits the EPA set as safe, and get better all the time.
The Minneapolis WTE facility, for example, uses the following process to control their emissions:
- Air is injected into the boiler to control nitrogen oxide emissions.
- Activated carbon is injected into the exhaust gases to control mercury.
- Flue gases then pass through a dry scrubber, where a lime slurry is injected to control sulfur dioxide and hydrochloric acid.
- Combustion gases pass through a bag house containing a series of fabric filters to remove particulate matter (ash), metals and dioxins.
Emissions are monitored on a continuous basis for multiple pollutants.
Using the antiscience playbook
Another common tactic is to use EPA data stating that trash burning is the largest source of cancer-causing dioxins. This is true, but the data refer to the uncontrolled backyard barrel burning of trash, and specifically not to WTEs.
These are the sort of antiscience tactics—quoting old data, misattributing data or results, cherry picking data—that have been used by climate change deniers.
Testing shows the ash to be non-toxic and it is widely used
WTEs reduce the volume of trash by about 90 percent, leaving about 10 percent in the form of ash that still needs to be landfilled unless it can be used elsewhere. Opponents often argue that the ash is toxic, but the EPA developed a test called the Toxicity Characteristic Leaching Procedure that tests the ash with an acidic liquid, causing any of forty identified contaminants, or reactive metals such as cadmium, to leach out. If these metals are found in amounts greater than a fraction of a percent, the ash is considered hazardous. Scientists have tested ash from every WTE facility in the country over the course of several years, and the tests have consistently shown that the ash is non-hazardous.
Consequently, about 3 million tons of concrete-like ash, or more than one-third of all WTE residue, are being reused annually as roadbed material, as daily and final landfill cover, as an aggregate in road construction, as an additive to asphalt, in the construction of artificial reefs, and in cement blocks. WTE operators are actively looking for other ways to reuse the concrete-like ash renewably instead of disposing of the balance in landfills. Mixing it into concrete is one solution that offsets the production of cement, which otherwise accounts for 5% of the world's carbon emissions.
The big one: WTEs fight climate change
Burning trash puts large amounts of carbon dioxide into the atmosphere. And the atmosphere is already at a dangerously high 400 parts per million of carbon dioxide—higher than it has been in at least 600,000 years. 350 parts per million is the maximum level many climate scientists consider safe and sustainable, which is still considerably higher than the roughly 290 ppm it was at the beginning of the industrial revolution.
Classed as low-carbon, renewable energy. But it turns out that while WTEs do emit greenhouse gases, they emit far fewer GHGs on a ton-for-ton basis than America's current practice of landfilling. In fact, 31 state pollution control agencies and two US territories now class WTEs as renewable energy and as preferable to landfilling. To understand why, consider a ton of post-recycled, post-composted trash in either of two scenarios: landfilled, or burned for energy with pollution capture technology.
Half of post-recycled MSW is part of the carbon cycle already. First, roughly 53 percent of post-recyled, post-composted trash is still derived from organic materials and so is part of Earth's carbon cycle anyway. Burning it does not increase the atmosphere's carbon load.
One ton MSW burned prevents one ton GHGs. Burning the remaining 47 percent, which is derived from petroleum carbon, prevents other, worse emissions. According to the EPA, every ton of garbage processed at a WTE facility actually prevents approximately one ton of emitted carbon-dioxide equivalent from going into the atmosphere.
Methane is a far worse GHG. One way this happens is by reducing landfilling. Landfills are the US's largest emitter of methane, a very potent greenhouse gas. According to the United Nations Intergovernmental Panel on Climate Change's Fourth Assessment on Climate Change, in a 20-year window methane is 72 times more potent a greenhouse gas than carbon dioxide. Capped landfills now have the technology to capture methane, but only about 34 percent of that methane is actually used to generate electricity. The rest leaks away or is flared off, and nothing at all is captured for the first few decades that a landfill sits open while being filled.
Metal recycling is built in to WTE. Next, post-recycled trash still contains millions of tons of metals that are sent to landfills. At a WTE facility, those metals are automatically reclaimed and recycled as a part of its normal filtration process. This saves the time, materials, energy, emissions and environmental disruption of mining for an equivalent amount of new minerals. The WTE operator Covanta Energy recycled 415,000 tons of ferrous and 16,800 tons of non-ferrous metals in 2012 alone—enough steel to build 28 Brooklyn Bridges and and enough aluminum to produce over one billion beverage cans.
The aluminum that is reclaimed by WTEs from the already post-recycled waste is particularly important. Recycling one ton of aluminum prevents a whopping 13.7 tons of GHG emissions, compared to 4.3 tons for office paper and 2.5 tons for newspaper. Recycling a ton of ferrous metal prevents 1.7 tons of GHG emissions. None of this is recaptured when a truck tips its load into a landfill.
Cutting waste transportation cuts carbon. WTE facilities are sited close to where the waste is generated, in or near urban areas. This eliminates much of the carbon emitted by hauling waste to a distant landfill. In 2011, New York City spent more than $300 million transporting its trash by train and truck— roughly 12,000 tons a day—to landfills as far as 300 miles away, emitting tons more carbon and wearing down roads and vehicles in the process. In some cases, such as e-waste, the US is now even exporting its waste to third world countries, vastly compounding its carbon contribution.
Energy generated offsets fossil fuels. WTE facilities generate heat and electricity, reducing the burning of fossil fuels for those same purposes. For example, the Minneapolis WTE facility currently generates enough electricity to power 25,000 homes, and enough steam to heat 1,500. Their proximity also means less heat and electricity are lost in transit.
Lower carbon than fossil fuel. According to the EPA burning municipal solid waste (MSW) in WTEs emits less carbon dioxide per megawatt hour than fossil fuels, including natural gas.
New gasification technologies coming online promise even greater energy capture and lower emissions than WTE by incineration.
Cleaning up U.S. lakes and rivers
Leachate is a hazardous tea created when rain percolates through garbage. Landfills capture this leachate and pump it to a treatment facility, where pollutants are removed through biological and chemical processes, then it is discharged into public waterways. But these treatment facilities rarely have the expensive reverse osmosis filters necessary to capture pharmaceuticals and other bioactive chemical products. These agents, including psychoactive drugs like antidepressants and cocaine, are turning up in groundwater throughout the United States and polluting even remote lakes and rivers. Their presence affects fish and other aquatic species, and they are now found in several municipal water supplies that are drawn from pharmaceutically polluted waters.
WTE facilities provide a safe way to destroy pharmaceuticals and other bioactive products that are disposed of in landfills or that people flush down the toilet. The high temperature of WTE combustion completely destroys the chemicals, rendering them inactive and ensuring cleaner lakes, rivers, and human water supplies and less pharmaceuticals and bioactive agents entering the food chain and affecting public health.
The times they are a changin'
So with all these benefits—efficiency, clean energy, reduced greenhouse gases, reduced transportation and road repair, reduced mining, freeing green space otherwise used for landfills, protecting groundwater and public waters, keeping the food chain cleaner, recycling metals—why haven't US liberals, who control the politics in many metropolitan areas where WTEs should be being built, been all over them like they have been in Europe? The answer lies in the history of the American public's views toward science.
Suspicion of corporations and of hidden dangers to health or the environment have become core and often unquestioned assumptions of the liberal US politics that grew up out of the birth of environmental science and the environmental movement. But these days there is a growing rift between the science and the movement in areas related to energy, climate and waste management. While liberals are justified in their concern about the hidden dangers that pollution can pose to health and the environment, in the case of Waste To Energy plants that view has not kept pace with the facts. This has led them to adopt policies that are less effective than other countries when it comes to managing waste and fighting climate change.
It's time for a change. American liberals and environmentalists who care about climate change need to reexamine the science and get behind expanded recycling and waste to energy programs. Fortunately for the sake of our children, a few bold leaders are starting to do just that.
A version of this article also appears on http://www.Ensia.com.
Shawn Lawrence Otto is a science writer, filmmaker, novelist, and the co-founder of ScienceDebate.org, the home of the US presidential science debates. His new book is Fool Me Twice: Fighting the Assault on Science in America. He lives in a wind-powered, passive solar, superinsulated geothermal home he designed and built with his own hands. He recycles, composts and drives a hybrid car. Visit him at www.shawnotto.com and like him on Facebook. Join ScienceDebate.org to get candidates to debate science.
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