According to the US EPA, in 2010 the US produced almost 250 million tons of municipal solid waste (MSW), of which only 12% was diverted towards waste-conversion (example: waste to energy) facilities. This generated approximately 14 million megawatt hours of electricity.
Landfilling is still the largest single means of trash disposal as more than half of all MSW produced in the US was sent to landfill in 2011 (The average American produces 4.4 pounds of waste per day with landfill diversion targets becoming more widespread and stringent). Diverting waste from a landfill to generate value from it is in itself a compelling reason to invest in waste conversion and/or waste to energy, however it also reduces greenhouse gas emissions.
In 2009, 17% of all human-related methane emissions in the US came from landfills. Further, the scarcity of land around urbanized areas means some municipalities are forced to transport waste long distances for disposal. For example, New York’s Department of Sanitation spends in excess of $300 million per year moving waste by truck to landfill and waste disposal facilities outside of the city.
PEAT’s TVRC is an innovative waste to energy technology that combines a thermal volume reduction (“TVR”) system on the front end with a core plasma-arc, plasma gasification PTDR system on the back-end for ash treatment. This combination maximizes electricity generation and minimizes residual by-product treatment.
Finally, in 2007, the EPA stated that waste to energy facilities comply with stringent air emissions standards and produce electricity with less environmental impact than almost any other source of electricity.
According to the United States Environmental Protection Agency’s “Solid Waste Management and Greenhouse Gases: A Lifecycle Assessment of Emissions and Sinks”, disposing of 650,000 tons per year in a landfill without gas collection, could reduce its Greenhouse Gas (GHG) emissions by about 260,000 Metric Tons Carbon Equivalent (MTCE) per year by managing waste in a mass burn combustor unit. For this preliminary discussion, this equates to 0.40 MTCE/ton avoided from landfilling.
However, the EPA’s document uses a combustion system efficiency of 550 kWh per ton of mixed MSW. The high temperature boiler/reactor system in the TVRC system, which combines a high temperature boiler/reactor with a plasma-arc, plasma gasification sytem, has an efficiency of approximately 690 kWh per ton – 25% greater efficiency; thus the high temperature boiler/reactor has the potential to generate approximately 0.50 MTCE/ton avoided from landfilling or in total up to 82,500 MTCE, when assuming 500 TPD.
Additionally, the EPA estimates greenhouse gas (GHG) emissions range from 10 to 20 million metric tons, depending on the different methods used to estimate the biogenic fraction of MSW. EPA’s eGrid (a database of information on electrical generators in the United States) indicates about 53% of the energy generated by MSW combustion facilities is from biogenic sources and 47% is fossil-fuel derived power. If we take that 53% and presume the same percent of GHG emissions are from biogenic sources, then MSW combustion facilities generate less GHGs than fossil-fuels.
||CO2 (lbs per MWh)
EPA estimates the GHG savings from WTE to be about 1 on of GHGs saved per ton of MSW combusted.
PEAT’s solution for municipal solid waste is the Thermal Volume Reduction & Conversion™ (“TVRC”) technology – an innovative system that combines a thermal volume reduction system with its core PTDR plasma-arc plasma gasification system.
Each TVRC system (modular) can process up to 250 tons per day of municipal solid waste (MSW) with no secondary pollution or unusable by-products generated: all feedstock represents a 100% waste diversion, eliminating the need for landfill disposal and/or further processing. It eliminates any future liabilities to the generators resulting from the use of outside collection, treatment and disposal services/facilities that are potentially unscrupulous. Further, a TVRC system generates high volume (over 8 to 1) and weight (over 4 to 1) reductions.
In a TVRC, MSW is first thermally processed in a high temperature reactor/boiler to generate steam. This steam is then processed in a full condensing steam-turbine generator for electricity production.
Any gas generated is processed through a flue gas cleaning system that removes any potentially harmful gases to surpass European emission standards.
Any fly ash generated in the high temperature reactor/boiler is processed is the PTDR plasma-arc plasma gasification & vitrification system. The PTDR converts the ash into an inert, non-leachable vitrified matrix that can be used in a variety of commercial applications including concrete aggregate, insulation, roadbed/fill construction and even in decorative and non-decorative tiles. Independent laboratory tests (i.e. “TCLP”) have proven that the vitrified matrix does not leach, is totally benign and safe for any re-utilization.
Any residual by-products generated in the gas cleaning systems (i.e. baghouse catches, scrubber residue, etc.) is collected and also processed in the PTDR system, thereby creating zero residual waste from the TVRC.