Waste-Based Energy: One Piece Of The Sustainable Energy Puzzle
Spittelau waste to energy plant provides district heating in Vienna. Image credit:Wikipedia
In the past few years, there's been much talk about the variety of available and developing technologies that could help secure a more sustainable energy future. Since October is Energy Awareness Month, the discussion of these energy alternatives is even more pertinent. You've probably heard about these developments, such as wind and solar power, as they have dominated headlines in the news and broad-scale discussions about renewable energy. But one technology that is both sustainable and consistently available yet rarely mentioned as an alternative to fossil fuels is waste-based energy. On average, Americans throw away 4.7 pounds of garbage each day - which equates to about 254 million tons of waste each year. While recycling and composting have proven to divert some of this waste from landfills, other options with waste exist that provide a sustainable source of energy. This waste-based energy can be created through a variety of technologies, including landfill gas-to-energy (LFGTE), waste-to-energy (WtE), and other emerging processes that convert waste into cleaner gases, fuels and additional sources of power.
Here are a few numbers to consider: nationwide, waste-to-energy facilities process nearly 30 million tons of trash each year and generate enough power to meet the needs of three million homes, allowing more than 36 million people in 27 states to rely on WtE plants. What's more, according to the EPA, waste-to-energy facilities produce electricity with "less environmental impact than almost any other source of electricity."
Keeping in mind the high volume of waste Americans produce, such facilities were designed to divert garbage from landfills, and also develop a viable and economical alternative to burning fossil fuels. This process involves extracting energy from trash in the form of high-pressure steam using high temperature combustion. The steam is converted into electricity in the turbine-generator, or provided in its base form to municipal or industrial heating systems. Wheelabrator Technologies, a wholly-owned subsidiary of Waste Management, operates 16 waste-to-energy facilities in the U.S. that process more than 21,000 tons of waste per day, generating 609 megawatts of power. In all, this delivers enough electricity to power more than 900,000 homes. To learn more about Wheelabrator and how the waste-to-energy system works, click here for pdf file.
Other waste-based technologies allow for the development of gas and fuel alternatives that can be used to power homes, fuel truck fleets and aid in other industrial processes. Following is an overview of just some of these game-changing technologies that Waste Management is currently using:
- Landfill gas to energy: Much of the waste sent to landfills is organic in nature - paper, food scraps and wood. As these items break down, they release gases that consist of approximately 50-60 percent methane and 40-50 percent carbon dioxide. At Waste Management's more than 100 LFGTE facilities across the U.S., the methane is collected and used to fuel onsite engines or turbines, generating electricity to power surrounding homes and neighborhoods. Additionally, landfill gas can be used to create liquefied natural gas (LNG), a clean fuel for vehicles. Waste Management, in a joint venture with Linde North America, will soon create the world's largest landfill gas to LNG facility in the world, capturing and reusing the gas to produce up to 13,000 gallons a day of transportation grade LNG to fuel the company's fleet of natural gas powered trash and recycling trucks.
- Plasma gasification: Right now, plasma gasification facilities are not as widespread as other waste-to-energy plants, but this may be about to change. Waste Management recently entered into a joint venture with InEnTec to create S4 Energy Solutions, which will develop, operate and market plasma gasification facilities throughout the U.S. using InEnTec's Plasma Enhanced Melter (PEM™) technology. With the PEM™ process, waste materials are fed into a closed chamber where they are superheated to temperatures of between 10,000 and 20,000 degrees Fahrenheit using an electricity-conducting gas called plasma. This intense heat rearranges the molecular structure of the waste materials, transforming them into an ultra-clean, synthesis gas (syngas).
- Clean syngas can be converted into a variety of other products, including transportation fuels such as ethanol and diesel, industrial products like hydrogen and methanol or even for electricity generation. In the secondary stage of the PEM™ process, inorganic (non-carbon-based) materials are transformed into environmentally beneficial glass products that could be used as a substitute for a number of construction applications. For a detailed video of this process, visit the S4 Energy Solutions Web site http://www.s4energysolutions.com/ and click "Play Video."
- MixAlco™ technology: Recently, Waste Management joined with Valero Energy Corporation to invest in Terrabon's unique waste-to-fuel conversion technology, MixAlco™. This technology converts organic waste streams into a variety of chemicals and secondary alcohols that can be further refined into renewable high-octane fuels, such as gasoline, jet fuel and diesel.
Amid the vast discussion of possible additions to America's renewable energy portfolio, we've rarely seen any mention of one clear resource that, for the time being, is ever-present: our waste. Waste remains a sustainable, indigenous resource in this country and can now be processed in such ways that provide a variety of energy solutions in a cleaner manner than through the typical burning of fossil fuels. While the development and use of waste-based technologies may not be the only path to energy independence, it's certainly something to consider - and a valuable piece of the puzzle that the waste management industry will use to lead us in the direction of a sustainable energy future.