Converting Waste to Energy Concurrent Workshop
15-‐04-‐23 Waste to Energy • Thermal Systems: • • • • • Converting Waste to Energy presented at: Association of Vancouver Island & Coastal Communities AGM and Convention Thermal Treatment or Conditioning Conversion Technologies Mass Burn Combustion Gasification, Pyrolysis, Or just plain – Incineration • Biological Systems 11 April, 2015 Courtenay, BC • Anaerobic digestion • Landfill gas recovery What we will talk about today • • • • Where does WTE fit in? The role of waste to energy (WTE) How WTE works What does it cost? Environmental and health impacts Reduce • 4th R - Recovery of energy and materials after the first 3Rs, prior to disposal • Common myths Reuse Recycle Recovery • Questions and discussion Residuals 3 4 The role of WTE in an Integrated System How Thermal WTE works • With recycling and organics treatment: Recycling Organic Treatment Thermal Treatment Landfill • Technologies offer different ways of releasing the energy in the waste • Conventional WTE systems are essentially power plants using waste as fuel instead of natural gas or wood • Advanced WTE systems use heat to convert the energy in the waste into a gas that can be burned for power, or converted to fuel (for burning) Landfill 1 15-‐04-‐23 Advanced thermal technologies: gasification/pyrolysis Conventional waste to energy Electricity Electricity Steam Heating Steam Gas Turbine or Recip. Engine Exhaust Exhaust Feedstock Preparation Combustion Energy Recovery Bottom Ash (60160 Waste to Energy 14Feb06.vsd) Burnaby, BC Mass Burn Facility (280,000 T/a) Flu Gas Cleaning Feedstock Preparation Gasification or Pyrolysis Syngas Cleaning Char / Ash Residue / Ash Energy Recovery Fly Ash (60160 Waste to Energy Pyrolysis 14Feb06.vsd) Wainwright WTE (10,000 T/a) • Showing the process steam line for energy utilization Gasification Plant in Edmonton 80,000 T/a Biological WTE • Anaerobic Digestion (AD) • • • • Page 11 Bacteria degrade organics and form methane Methane is captured and cleaned Can be burned as fuel, or Upgraded to natural gas quality (to be used as fuel) 12 2 15-‐04-‐23 Anaerobic Process Organics separated from waste stream Pulping and decontamination of feedstock AD Pictures Material fed into reactor Biogas recovered from reactor Energy recovery Digestate removed from reactor Liquid fraction recycled Solids dewatered Aerobic composting 14 Bioreactor Landfill Energy Comparison Potential kWh per tonne of waste 800 700 600 500 400 300 200 100 0 Thermal WTE Gasifica>on WTE Anaerobic Diges>on Courtesy SSWM Page 15 Bioreactor Landfill 16 Waste Diversion Potential • Thermal WTE • Takes 100% of residual waste after recycling • 75% converted to energy • 25% to landfill as ash Landfill Reduction • Biological WTE • Takes 35 – 40% of waste (Organic part) What still goes to landfill in % by weight 120 100 • 60% to 65% still goes to landfill • About half of the diverted organics become compost • The rest goes towards making energy 80 60 40 20 0 Thermal WTE 17 Gasifica>on WTE Anaerobic Diges>on Bioreactor Landfill 18 3 15-‐04-‐23 Economies of Scale for Thermal WTE Cost comparison $ per tonne comparative estimates, including capital repayment Courtesy Ramboll (developed for York – Durham) 150 100 50 0 Thermal WTE Gasifica>on WTE Anaerobic Diges>on Bioreactor Landfill 19 20 Long term WTE costs versus Landfill Environmental Issues • Air emissions • Emission standards more stringent than for most wood fired power plants or industrial boilers • In Europe, air emissions from WTE considered irrelevant compared to industry and transportation • Residues from thermal systems • Bottom ash generally safe to dispose in landfill or use as cover • Fly ash (5%) needs to be stabilized before landfilling • AD residue is compost, which can be land applied 21 Reduction of Mercury from WTE in the USA Dioxin Emissions in the USA Source: (P. Deriziotis, MS Thesis, Columbia University, 2003; data by U.S. EPA) Source: Waste-toEnergy Research and Technology Council (WTERT) 4 15-‐04-‐23 GHG Emissions from Thermal Electricity Production Comparing GHG Emissions Tonnes CO2e Reduced per Tonne Material Handled Tonnes 2.5 1.5 Composting 0.5 -0.5 Steel Paper Plastics Anaerobic Digestion Yard & Food Yard & Food Garden Scraps Garden Scraps 1000 CO2e emissions (kg/MWh) Recycling 3.5 500 0 Residual Coal Waste Thermal Treatment Natural Gas (CCGT) MSW BC Energy Intensity Myths – true or false Myths (continued 2) • Thermal WTE has no future • Revenues from WTE can pay for everything and put money back into the community • False: there are 800 plants worldwide and over 400 in Europe, with many new ones on the way • False: Capital and operating costs are too high to be fully offset by energy revenues • Thermal WTE will reduce recycling • False; those countries with the highest WTE also have the highest recycling • Emerging technologies carry a high risk • True: Many promises are made, but most cannot deliver. See Plasco example • WTE will eliminate the need for landfills • False: landfills will be needed for ash, for downtime and to handle growth 27 • Thermal systems can cause health issues • False: Modern systems have not been linked to health issues 28 Myths (continued 3) Myths (continued 4) • WTE is too expensive for smaller communities: • WTE facilities will never be sited anywhere close to anyone • True: In most cases, maximized recycling and landfill will be less costly (if landfill capacity is available) • False: see location of WTE plant in downtown Paris • AD is growing worldwide and pays for itself: • False: AD plant construction in Europe has slowed to a crawl because subsidies have been reduced. • Current energy prices are hurting WTE projects • True: Even large scale plants need good energy revenues to keep tipping fees reasonable 29 30 5 15-‐04-‐23 THANK YOU QUESTIONS AND DISCUSSION 6
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