Trash talking

Trash talking

Trash talking is not new to society however recently there has been an increasing amount of it. Specifically surrounding the debate regarding the benefits of landfills turning trash into power. While waste-to-energy technology has been around since the 1930s, as the ‘green’ movement has picked up speed so has technology dedicated to transforming our trash into ‘clean, green energy’. However is this all just a load of trash? Not according to the EPA, which has it’s own Landfill Methane Outreach Program (LMOP).

Overview

As garbage decomposes in landfills it emits landfill gas (LFG) consisting of fifty percent methane, which according to the EPA has 20x the global warming potential of carbon dioxide. In fact, “each pound of trash you throw away will emit approximately 0.94 pounds of carbon dioxide equivalent in the form of methane, and the average person in the U.S. throws away over 1,130 pounds of waste per year. For every person in the U.S., about 1,060 pounds of CO2 equivalent comes from the garbage we throw out every year.” Since methane is produced during the natural decomposition process it provides a constant power source, or so believes the 519 companies that now invest in this process. Nationally, landfill gas projects have increased 30% from 2005 to 2010. Below is a current map, courtesy of the EPA, of nationwide landfills as of December 16, 2009.

Landfill Gas Energy Projects and Candidate Landfills[1]

Success story?

While it is hard to imagine that the trash we throw away would be considered safe and clean, many companies have drank the kool-aid and are investing billions of dollars in our trash. Houston based company, Waste Management, is one such example. Waste Management currently runs around 115 landfill gas-to-energy projects. The company has even gone a step further and partnered with the North American engineering unit of Linde Group to build a $15.5 million liquefied natural gas (LNG) facility near Livermore, California. This LNG plant will use LFG to produce clean fuel that will help power about 300 Waste Management collection trucks. As Waste Managements, Director of Communication, Wes Muir stated, “It’s a great use for our landfill gas”.

Safe or dirty?

Turning trash into efficient sources to fuel trucks is good in theory however how safe is this technology? According to the EPA small amounts of dioxins/furans can be released during the LFG combustion process. Specifically, “based on national and international source tests, the concentration of dioxins from LFG combustion ranges from non–detectable to 0.1 nanograms (10–9 grams) of toxic equivalents per dry standard cubic meter of exhaust, at 7 percent oxygen.” Even with the release of toxins, the EPA claims that mercury emissions from combusted trash is safer than emissions released from ‘uncontrolled’ LFG. Personally I think this is a load garbage.


[1] http://www.epa.gov/lmop/



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3 Comments

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3 responses to “Trash talking

  1. Aaron Townsend

    I think you may be confusing two different technologies. Waste-to-energy technology burns the trash directly, and although the emissions have been lowered drastically in the last 15 years, the emissions of dioxins, mercury, etc are still higher than coal or other combustion sources per MWh of electricity generated. With waste-to-energy technology, the trash is converted to ash before it gets to the landfill. On the other hand, the EPA landfill gas outreach program focuses on capturing landfill gas that occurs naturally as the trash in the landfill decomposes. Combusting these gases generates some electricity but its main purpose is to reduce the amount of methane and other hydrocarbon gases that escape from the landfill. It does not increase the amount of mercury that is emitted.

  2. blackpressinc

    Great blog post.

    Turning trash to waste is a very interesting technology that’s been evolving for years. One of it’s best features is that it doesn’t necessarily have to generate energy for it to be successful. Cities like New York pay around $150/ton of waste for disposal and more money is saved when used as an alternative of expensive recycling plants. This means that a plant can operate without generating net electricity but as the process becomes more efficient they gain profits from lower operating costs and the ability to charge for electricity.

    One of the most recent methods has been using massive graphite electrodes and passing trash through an electric arc which turns the trash into a plasma. The plasma releases heat which is used to power a boiler and create electricity. Some of the difficulties had been arc control in a changing environment and maintenance because a small percentage of the waste is converted into a highly toxic slag at around 1~5% of the original trash volume.

    This technique has the benefit of generating a substantial amount of electricity while disposing of significant amounts of waste. Look forward to waste to energy in the future.

    http://www.entrepreneur.com/tradejournals/article/166944606.html

    http://science.discovery.com/videos/invention-nation-trash-furnace.html

    http://www.scientificamerican.com/article.cfm?id=medical-waste-gas-energy

  3. ll22584

    I’m a bit confused,
    – first I’m not sure if this LFG technology you’re talking about is the same as the waste-to-energy technology (which have been around for decades), if not, then how are they different?
    – Like the first commentor mentioned, conventional waste-to-energy combusts municipal trash and make use of the heat generated from the process while reducing the mass of trash by 90%+. This technology is widely applied in Europe and is gaining popularity in the U.S. As far as emission goes, however, according to my research, WTE plants are currently the cleanest electricity generators in the country [1]. This is the result of EDA’s regulation which required all WTE plants to employ the most advanced gas treatment technologies. Also, combusting 1lb of trash will produced approx. 1lb equivalent of CO2, whereas, putting 1lb of trash into landfill will generate 2 times the GHG equivalent of methane; making WTE a superior waste-treatment option to landfill. Currently, the WTE facilities in the U.S. is generating 2700MW of energy per year!

    – The landfill gas to energy concept is really interesting, thought it seems to offer more potential in reducing methane production from landfills and less effecient in its ability to generate energy. I’m really curious about the technology in general, specifically how the methane is captured.

    – I’m also a bit confused about your opinion on the topic, all of the information you poses this technology in a positive light, but you seem to be disapproving of it, what is your rational behind it?

    [1] http://web.archive.org/web/20071009073636/www.wte.org/docs/epaletter.pdf

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