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Waste-to-Energy: a mountain of trash, or a pile of energy?

The views expressed are those of the author and are not necessarily those of Scientific American.

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By, Melissa C. Lott and David Wogan

The Baltimore Sun recently ran an article about the need for new power plants in Maryland and a proposal to use garbage as the fuel for some new generation facilities. The article’s focus was apparently supposed to be on how utilities can finance new construction. But, in its opening, the article highlighted the active debate surrounding waste-to-energy as a “green” power source. According to the article:

There is some question about whether the electricity plant planned for a vacant, brown patch on Baltimore’s waterfront would be truly “green” and “renewable.”

The generator built by Energy Answers would burn waste otherwise destined for the dump. It would blow carbon dioxide and other unnatural stuff into the air. Its backers say it’s cleaner than a coal-burning plant and will save many acres of landfill space.

Below is an article that we wrote about Waste-to-Energy and its dirty reputation.

Collect trash, burn it, and then generate electricity. The technology is called Waste-to-Energy, and it uses our waste streams to produce electricity that can be cleaner than the average kilowatt-hour (kWh) generated in the United States today. A mountain of trash becomes a pile of energy. But, will this domestic renewable resource be able to move beyond its “dirty” reputation to become a larger portion of the U.S. electricity supply?

European countries have embraced Waste-to-Energy (WTE) as a way to reduce landfill growth as well as dependence on imported fuels. Today, about 400 WTE facilities are operating in Europe, using municipal solid waste as their primary fuel source. In Denmark alone, 29 WTE plants are currently in operation with 10 more on the way. In Sweden, the city of Kristianstad has essentially weaned itself off of fossil fuels in just ten years by replacing these energy sources with the city’s own waste.

In the United States, only 86 plants use municipal solid waste as fuel. The amount of trash that these facilities process is dropping – by more than 7% from 2006 to 2008. And very few new facilities are being discussed.

Why is the United States so far behind?

On the surface, WTE looks like a feasible option in the United States’ search for renewable and domestic energy resources. Today’s WTE technology is safe – assuming you can separate out hazardous materials (like batteries) in the incoming fuel (trash). In areas where tipping fees are high – primarily major metropolitan areas – these facilities can be economically viable without government subsidies.

If deployed nationwide, WTE facilities could reduce the volume of the more than 250 million tons of material being thrown away each year by up to 90%. If burned properly, the remaining 10% would be mostly inert ash. With proper filtering systems in place, WTE facilities can meet and even exceed federal air emissions standards. But, despite these positive environmental attributes, the concept of burning trash does not appear able to shake its “dirty” image in America.

In Austin, Texas, Waste-to-Energy has been a “dirty” word for more than 30 years. In 1984, voters authorized bond money for the construction of a WTE plant on the edge of the city. But, vocal opposition from environmental activists and resulting runaway project costs led to a showdown that would scuttle the project 8 years later. The bad-blood resulting from this ordeal still runs thick today. Even when faced with a 30% renewable energy requirement (WTE qualifies), Austin’s city government and local utility (Austin Energy) did not seriously consider any WTE proposals. Instead, city residents receive renewable power primarily from wind farms in West Texas. They will soon buy power from a 100 MW biomass facility that will burn wood chips (not trash), located hundreds of miles to the east of Austin.

A different story has played out on the East Coast – home to high tipping fees and limited land availability for new landfills. In 1984, while Austinites were arguing over the environmental benefits (and costs) of a WTE facility, Baltimore residents were celebrating the opening of the city’s own Waste-to-Energy plant. Still in operation today – and profitable without government subsidies – the Refuse and Energy Systems Company (RESCO) facility processes about 2,250 tons of trash per day. The facility produces enough electricity to power 40,000 homes, as well as steam for the heating and cooling of local commercial buildings. According to RESCO employees, this no-sort facility has also improved local water quality, because of strict discharge requirements for power generation facilities.

So, why were these experiences so different?

Economics and land availability played significant roles in the decisions in Austin and Baltimore. But, these experiences also showed how WTE’s image problem can be a significant roadblock. Its “dirty” stigma has and could continue to prevent the expanded use of this technology in the United States even under favorable economic conditions. Until Americans become tired of dedicating space for new landfills, the country’s mountain of trash is unlikely to become a pile of energy. And waste will remain an untapped domestic renewable energy resource.

Photo Credit:

1. Photo of crane with garbage at Vestforbrænding, courtesy of Vestforbrænding and found using Creative Commons.

[This post was originally published on 12/16/2010 on Scientific American’s Guest Blog]

Melissa C. Lott About the Author: An engineer and researcher who works at the intersection of energy, environment, technology, and policy. Follow on Twitter @mclott.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. pdcaton 8:14 pm 09/19/2011

    Waste to energy is just about the best compromise one can reach on renewable energy.

    People will not stop consuming goods, and this results in waste. Wealthy countries create huge amounts of waste. This waste generates MORE greenhouse gas (methane) if landfilled than when burned (carbon dioxide). And when coupled with the other environmental concerns with landfills (groundwater contamination, space requirements, aesthetics, etc), the by-products of combustion have additional uses while burial does not. And the average calorific value of waste is fairly consistent, allowing for a predictable power output, which other renewables cannot provide. People are used to having access to power on demand, and this behaviour is hard to change.

    It is a straightforward process to use electrostatic precipitators to remove ash and ionized compounds from the waste stream post combustion. This can be teamed with scrubbers, but that is not always necessary to meet emissions standards. Much depends on the source waste stream, a primarily residential stream has much fewer toxins than an industrial one.

    The ash can then either be buried, or more practically, used to create concrete. Cement bonds well with the ash, and ameliorates many compounds that would otherwise leach into the environment. Any metals can also be more easily separated from the waste after combustion, and then recycled.

    It surprises me that the US has been so slow to embrace this technology.

    Link to this
  2. 2. kwilson962 3:15 am 09/20/2011

    Thermal depolymerization is also an option for trash. The energy efficiency is upwards of 85%, depending on the material. The process can handle prions and even anthrax, producing environmentally benign materials from toxic waste. The only material that cannot be handled is radioactive material.

    “Anything Into Oil” ( outputs water, minerals, oil, and gas (which is used to power the process). For instance, 100 pounds of medical waste is converted to 65 pounds oil, 10 pounds gas, 5 pounds carbon and metal solids, and 20 pounds of water. The process can handle municipal liquid waste, plastic bottles, all kinds of tires, infectious medical waste, old computers, and heavy oil, including refinery residues and tar sands.

    This would seem to be better and safer than the burning of trash with a 30% efficiency.

    Link to this
  3. 3. davidwogan 11:01 pm 09/20/2011

    Thanks for the comments. As both of y’all point out, the technology for waste-to-energy is readily available. The resistance lies in public perception of WTE, and public policies. It is just cheaper to throw away garbage than do something else with it, like create energy.

    Link to this
  4. 4. khernau 5:23 pm 03/6/2012

    Great post! It would fantastic if we could use waste to create energy. That would be one heck of a power saver! I always try to save what power I can and recycle. Anything for mother earth!

    Link to this

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