Waste to Energy

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Waste-to-energy

Spittelau incineration plant is one of several plants that provide districtheating in Vienna.

Waste-to-energy or energy-from-waste is theprocess of generating energy in the form ofelectricity and/or heat from the incineration ofwaste. WtE is a form of energy recovery. MostWtE processes produce electricity and/or heatdirectly through combustion, or produce acombustible fuel commodity, such as methane,methanol, ethanol or synthetic fuels.[1]

Incineration

Main article: IncinerationIncineration, the combustion of organic materialsuch as waste with energy recovery, is the mostcommon WtE implementation. All new WtEplants in OECD countries incinerating waste(residual MSW, commercial, industrial or RDF)must meet strict emission standards, includingthose on nitrogen oxides (NOx), sulphur dioxide(SO2), heavy metals and dioxins. Hence, modernincineration plants are vastly different from oldtypes, some of which neither recovered energynor materials. Modern incinerators reduce thevolume of the original waste by 95-96 percent,depending upon composition and degree ofrecovery of materials such as metals from the ash for recycling.[2]

Incinerators may emit fine particulate, heavy metals, trace dioxin and acid gas, even though these emissions arerelatively low[3] from modern incinerators. Other concerns include proper management of residues: toxic fly ash,which must be handled in hazardous waste disposal installation as well as incinerator bottom ash (IBA), which mustbe reused properly.[4]

Critics argue that incinerators destroy valuable resources and they may reduce incentives for recycling. The question,however, is an open one, as countries in Europe recycling the most (up to 70%) also incinerate their residual waste toavoid landfilling.Incinerators have electric efficiencies of 14-28%. In order to avoid losing the rest of the energy, it can be used fore.g. district heating (cogeneration). The total efficiencies of cogeneration incinerators are typically higher than 80%(based on the lower heating value of the waste), and may even exceed 100% when equipped with flue gascondensation.The method of using incineration to convert municipal solid waste (MSW) to energy is a relatively old method of WtE production. Incineration generally entails burning waste (residual MSW, commercial, industrial and RDF) to boil water which powers steam generators that make electric energy and heat to be used in homes, businesses, institutions and industries. One problem associated with incinerating MSW to make electrical energy, is the potential for pollutants to enter the atmosphere with the flue gases from the boiler. These pollutants can be acidic and in the 1980s were reported to cause environmental damage by turning rain into acid rain. Since then, the industry has

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removed this problem by the use of lime scrubbers and electro-static precipitators on smokestacks. By passing thesmoke through the basic lime scrubbers, any acids that might be in the smoke are neutralized which prevents the acidfrom reaching the atmosphere and hurting the environment. Many other devices such as fabric filters, reactors andcatalysts destroy or capture other regulated pollutants. According to the New York Times, modern incinerationplants are so clean that "many times more dioxin is now released from home fireplaces and backyard barbecues thanfrom incineration. " According to the German Environmental Ministry, "because of stringent regulations, wasteincineration plants are no longer significant in terms of emissions of dioxins, dust, and heavy metals".

WtE technologies other than incinerationThere are a number of other new and emerging technologies that are able to produce energy from waste and otherfuels without direct combustion. Many of these technologies have the potential to produce more electric power fromthe same amount of fuel than would be possible by direct combustion. This is mainly due to the separation ofcorrosive components (ash) from the converted fuel, thereby allowing higher combustion temperatures in e.g.boilers, gas turbines, internal combustion engines, fuel cells. Some are able to efficiently convert the energy intoliquid or gaseous fuels:Thermal technologies:• Gasification (produces combustible gas, hydrogen, synthetic fuels)• Thermal depolymerization (produces synthetic crude oil, which can be further refined)• Pyrolysis (produces combustible tar/biooil and chars)• Plasma arc gasification or plasma gasification process (PGP) (produces rich syngas including hydrogen and

carbon monoxide usable for fuel cells or generating electricity to drive the plasma arch, usable vitrified silicateand metal ingots, salt and sulphur)

Non-thermal technologies:• Anaerobic digestion (Biogas rich in methane)• Fermentation production (examples are ethanol, lactic acid, hydrogen)• Mechanical biological treatment (MBT)

• MBT + Anaerobic digestion• MBT to Refuse derived fuel

Global WTE developmentsDuring the 2001-2007 period, the WTE capacity increased by about four million metric tons per annum. Japan andChina built several plants that were based on direct smelting or on fluidized bed combustion of solid waste. In Chinathere are about 50 WTE plants. Japan is the largest user in thermal treatment of MSW in the world with 40 milliontons. Some of the newest plants use stoker technology and others use the advanced oxygen enrichment technology.There are also over one hundred thermal treatment plants using relatively novel processes such as direct smelting,the Ebara fluidization process and the Thermo- select -JFE gasification and melting technology process.[5] In Patras,Greece, a Greek company just finished testing a system that shows potential. It generates 25kwatts of electricity and25kwatts of heat from waste water.[6] In India its first energy bio-science center was developed to reduce thecountry’s green house gases and its dependency on fossil fuel.[7]

Biofuel Energy Corporation of Denver, CO, opened two new biofuel plants in Wood River, NE, and Fairmont, MN,in July 2008. These plants use distillation to make ethanol for use in motor vehicles and other engines. Both plantsare currently reported to be working at over 90% capacity. Fulcrum BioEnergy incorporated located in Pleasanton,CA, is currently building a WTE plant near Reno, NV. The plant is scheduled to open in early 2010 under the nameof Sierra BioFuels plant. BioEnergy incorporated predicts that the plant will produce approximately 10.5 milliongallons per year of ethanol from nearly 90,000 tons per year of MSW.(Biofuels News)

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Waste to energy technology includes fermentation, which can take biomass and create ethanol, using waste cellulosicor organic material. In the fermentation process, the sugar in the waste is changed to carbon dioxide and alcohol, inthe same general process that is used to make wine. Normally fermentation occurs with no air present. Esterificationcan also be done using waste to energy technologies, and the result of this process is biodiesel. The cost effectivenessof esterification will depend on the feedstock being used, and all the other relevant factors such as transportationdistance, amount of oil present in the feedstock, and others.[8] Gasification and pyrolysis by now can reach grossthermal conversion efficiencies (fuel to gas) up to 75%, however a complete combustion is superior in terms of fuelconversion efficiency.[9] Some pyrolysis processes need an outside heat source which may be supplied by thegasification process, making the combined process self-sustaining.

Carbon dioxide emissionsIn thermal WtE technologies, nearly all of the carbon content in the waste is emitted as carbon dioxide (CO2) to the atmosphere (when including final combustion of the products from pyrolysis and gasification; except whenproducing bio-char for fertilizer). Municipal solid waste (MSW) contain approximately the same mass fraction ofcarbon as CO2 itself (27%), so treatment of 1 metric ton (1.1 short tons) of MSW produce approximately 1 metric ton (1.1 shorttons) of CO2.In the event that the waste was landfilled, 1 metric ton (1.1 short tons) of MSW would produce approximately 62cubic metres (2,200 cu ft) methane via the anaerobic decomposition of the biodegradable part of the waste. Thisamount of methane has more than twice the global warming potential than the 1 metric ton (1.1 short tons) of CO2, which would have been produced by combustion. In some countries, large amounts of landfill gas are collected,but still the global warming potential of the landfill gas emitted to atmosphere in e.g. the US in 1999 wasapproximately 32% higher than the amount of CO2 that would have been emitted by combustion.[10]

In addition, nearly all biodegradable waste is biomass. That is, it has biological origin. This material has been formedby plants using atmospheric CO2 typically within the last growing season. If these plants are regrown the CO2 emitted from their combustion will be taken out from the atmosphere once more.Such considerations are the main reason why several countries administrate WtE of the biomass part of waste asrenewable energy.[11] The rest—mainly plastics and other oil and gas derived products—is generally treated asnon-renewables.

Determination of the biomass fractionMSW to a large extent is of biological origin (biogenic), e.g. paper, cardboard, wood, cloth, food scraps. Typicallyhalf of the energy content in MSW is from biogenic material. Consequently, this energy is often recognised asrenewable energy according to the waste input.Several methods have been developed by the European CEN 343 working group to determine the biomass fraction ofwaste fuels, such as Refuse Derived Fuel/Solid Recovered Fuel. The initial two methods developed (CEN/TS 15440)were the manual sorting method and the selective dissolution method. A detailed systematic comparison of thesetwo methods was published in 2010.[12] Since each method suffered from limitations in properly characterizing thebiomass fraction, two alternative methods have been developed.The first method uses the principles of radiocarbon dating. A technical review (CEN/TR 15591:2007) outlining the carbon 14 method was published in 2007. A technical standard of the carbon dating method (CEN/TS 15747:2008) will be published in 2008.Wikipedia:Manual of Style/Dates and numbers#Precise language In the United States,

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there is already an equivalent carbon 14 method under the standard method ASTM D6866.The second method (so-called balance method) employs existing data on materials composition and operatingconditions of the WtE plant and calculates the most probable result based on a mathematical-statistical model.[13]

Currently the balance method is installed at three Austrian and eight Danish incinerators.A comparison between both methods carried out at three full-scale incinerators in Switzerland showed that bothmethods came to the same results.[14]

Carbon 14 dating can determine with precision the biomass fraction of waste, and also determine the biomasscalorific value. Determining the calorific value is important for green certificate programs such as the RenewableObligation Certificate program in the United Kingdom. These programs award certificates based on the energyproduced from biomass. Several research papers, including the one commissioned by the Renewable EnergyAssociation in the UK, have been published that demonstrate how the carbon 14 result can be used to calculate thebiomass calorific value. The UK gas and electricity markets authority, Ofgem, released a statement in 2011accepting the use of Carbon 14 as a way to determine the biomass energy content of waste feedstock under theiradministration of the Renewables Obligation.[15] Their Fuel Measurement and Sampling (FMS) questionnairedescribes the information they look for when considering such proposals.[16]

Examples of waste-to-energy plantsAccording to ISWA there are 431 WtE plants in Europe (2005) and 89 in the United States (2004).[17] The followingare some examples of WtE plants.Waste incineration WtE plants• Lee County Solid Waste Resource Recovery Facility, Fort Myers, Florida, USA (1994)[18]

• Montgomery County Resource Recovery Facility in Dickerson, Maryland, USA (1995)• Spittelau (1971), and Flötzersteig (1963), Vienna, Austria (Wien Energie [19])• SYSAV in Malmö (2003 and 2008), Sweden (Flash presentation [20])• Algonquin Power, Brampton, Ontario, Canada[21]

• Teesside EfW plant near Middlesbrough, North East England (1998)• Edmonton Incinerator in Greater London, England (1974)• Burnaby Waste-to-Energy Facility, Metro Vancouver, Canada (1988).Liquid fuel producing plants (planned or under construction)• Cynar PLC: The technology is pyrolysis of plastic with destillation of the pyrolysis oil into several liquid fuels.

Cynar has one operating demonstration plant in Portlaoise, Ireland. The first commercial plant with an annualcapacity of 6.000 tonnes of plastics in Bristol, UK commenced commissioning in October 2013.[22] A secondcommercial plant is under construction in Almeria, Spain.[23] According to Cynar, approximately 1,000 litres ofusable liquid fuel can be produced for every tonne of plastic.[24]

• Edmonton Waste-to-ethanol Facility, Enerkem-process, fueled by RDF, initially scheduled for completion 2010,.Commissioning of front-end systems commenced December 2013, and Enerkem then expected initial methanolproduction during 2014.[25] Located in Edmonton, Alberta, Canada.

• Mississippi Waste-to-ethanol Plant, Enerkem-process, initially scheduled for completion 2013. Pontotoc,Mississippi, USA.[26] As of February 2014 still in under development.

Plasma Gasification Waste-to-Energy plants•• The US Air Force Transportable Plasma Waste to Energy System (TPWES) facility (PyroGenesis technology) at

Hurlburt Field, Florida.Besides large plants, domestic waste-to-energy incinerators also exist. For example, the refuge de Sarenne has adomestic waste-to-energy plant. It is made by combining a wood-fired gasification boiler with a Stirlingmotor.[27][28]

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References[1] NW BIORENEW (http:/ / nwbiorenew. com/ Technologies. htm)[2] Waste to Energy in Denmark (http:/ / www. zmag. dk/ showmag. php?mid=wsdps) by Ramboll Consult[3] Emissionsfaktorer og emissionsopgørelse for decentral kraftvarme (http:/ / www2. dmu. dk/ 1_viden/ 2_Publikationer/ 3_fagrapporter/

rapporter/ FR442. pdf), Kortlægning af emissioner fra decentrale kraftvarmeværker, Ministry of the Environment of Denmark 2006 (inDanish)

[4] Waste Gasification: Impacts on the Environment and Public Health (http:/ / www. bredl. org/ pdf/ wastegasification. pdf)[5] columbia university (http:/ / www. engineering. columbia. edu/ announcements/ 2008/ Wtert_mtg10-31-08/ index. html)[6] clean-tech-Greece (http:/ / cleantech. com/ news/ 3874/ swedens-morphic-sells-waste-energy-system)[7] clean-tech- India (http:/ / cleantech. com/ news/ 4536/ mumbai-institute-opens-india)[8] bionomic fuel (http:/ / www. bionomicfuel. com/ cost-effective-waste-to-energy-technologies/ )[9] The Viability of Advanced Thermal Treatment of MSW in the UK (http:/ / www. esauk. org/ reports_press_releases/ esa_reports/

thermal_treatment_report. pdf) by Fichtner Consulting Engineers Ltd 2004[10] Themelis, Nickolas J. An overview of the global waste-to-energy industry (http:/ / www. seas. columbia. edu/ earth/ papers/

global_waste_to_energy. html), Waste Management World 2003[11] (http:/ / www. r-e-a. net/ power/ biomass-bioenergy/ energy-from-waste), from the homepage of the UK Renewable Energy Association[12] The biogenic content of process streams from mechanical–biological treatment plants producing solid recovered fuel. Do the manual

sorting and selective dissolution determination methods correlate? (http:/ / www. sciencedirect. com/ science?_ob=ArticleURL&_udi=B6VFR-4YBMT6V-4& _user=217827& _coverDate=07/ 31/ 2010& _alid=1412152242& _rdoc=1& _fmt=high& _orig=search&_cdi=6017& _docanchor=& view=c& _ct=2& _acct=C000011279& _version=1& _urlVersion=0& _userid=217827&md5=565ba44df8165c6b99c6722f5fbe30c5) by Mélanie Séverin, Costas A. Velis, Phil J. Longhurst and Simon J.T. Pollard., 2010. In: WasteManagement 30(7): 1171-1182

[13] A New Method to Determine the Ratio of Electricity Production from Fossil and Biogenic Sources in Waste-to-Energy Plants. by Fellner, J.,Cencic, O. and Rechberger, H., 2007. In: Environmental Science & Technology, 41(7): 2579-2586.

[14] Determination of biogenic and fossil CO2 emitted by waste incineration based on 14CO2 and mass balances. by Mohn, J., Szidat, S., Fellner,J., Rechberger, H., Quartier, R., Buchmann, B. and Emmenegger, L., 2008. In: Bioresource Technology, 99: 6471-6479.

[15] http:/ / www. ofgem. gov. uk/ Sustainability/ Environment/ RenewablObl/ FuelledStations/ Documents1/ 14C%20publicity. pdf[16] http:/ / www. ofgem. gov. uk/ Pages/ MoreInformation. aspx?docid=363& refer=Sustainability/ Environment/ RenewablObl/

FuelledStations[17] Energy from Waste (http:/ / www. iswa. org/ index. php?eID=tx_iswaknowledgebase_download& documentUid=1649) State-of-the-Art

Report, Statistics 5th Edition August 2006. International Solid Waste Association (ISWA)[18] Energy-from-Waste facility in Lee County (http:/ / www. covantaenergy. com/ facilities/ facility-by-location/ lee. aspx) run as Covanta Lee,

Inc.[19] http:/ / www. wienenergie. at/[20] http:/ / www. sysav. se/ upload/ flash/ sysav. swf[21] Algonquin Power Energy from Waste Facility (http:/ / www. algonquinpower. com/ business/ facility/ alternative_peel. asp) from the

homepage of Algonquin Power[22] Linkedin job offer: Operation Manager at Cynar (http:/ / www. linkedin. com/ jobs2/ view/ 9634788)[23] The Market Autum 2013 at Enterprise-Ireland webpage (http:/ / www. enterprise-ireland. com/ eReader/ TheMarket/

TheMarketAutumn2013/ files/ assets/ seo/ page30. html)[24] Cynar powerpoint presentation at Marine Litter, October 3rd 2013 (http:/ / www. gpa. unep. org/ index. php/

global-partnership-on-nutrient-management/ publications-and-resources/ second-global-conference-on-land-ocean-connections-gloc-2/216-murray-successfully-converting-end-of-life-plastics-to-liquid-fuels/ file?limit=20& start=40)

[25] Enerkem press release December 2013 (http:/ / www. prnewswire. com/ news-releases/enerkem-begins-commissioning-of-front-end-systems-at-the-enerkem-alberta-biofuels-facility-in-edmonton-canada-234229341. html) foundat the PR Newswire webpage.

[26] Enerkem. Pontotoc MSW-to-Biofuels plant (http:/ / www. enerkem. com/ en/ our-locations/ plants/ pontotoc-mississippi. html).[27] Refuge de Sarenne waste incinerator hooked up to Stirling motor (http:/ / www. connaissancedesenergies. org/

un-refuge-de-montagne-au-sommet-de-l-autonomie-energetique-120705)[28] Refuge de Sarenne using wood-fired gasification boiler (http:/ / ca-en. franceguide. com/

Environmentally-conscious-accommodations-in-the-Alps. html?NodeID=1& EditoID=200054)

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Further reading• Field, Christopher B. "Emissions pathways, climate change, and impacts." PNAS 101.34 (2004): 12422–12427.• Sudarsan, K. G., and Mary P. Anupama. "The Relevance of Biofuels." Current Science 90.6 (2006): 748. 18 Oct.

2009 <http://www.iisc.ernet.in/currsci/mar252006/748a.pdf>.• Tilman, David. "Environmental, economic, and energetic costs." PNAS 103.30 (2006): 11206–11210.• "Biofuels News". Chemical Engineering Progress. . FindArticles.com. 18 Oct. 2009.

<http://findarticles.com/p/articles/mi_qa5350/is_200808/ai_n28083407>• “Waste to Ethanol." Centurymarc. 2007. 10

External links• Waste-to-Energy Research and Technology Council (http:/ / www. seas. columbia. edu/ earth/ wtert)• WtERT Germany (http:/ / www. wtert. eu)• LowCarbonEconomy.com (http:/ / www. lowcarboneconomy. com)• Gasification Technologies Council (http:/ / www. gasification. org/ )• Google Map of Municipal Waste-To-Energy Plants: the privatization of government services (http:/ / maps.

google. com/ maps/ ms?msid=202977755949863934429. 0004f040169ee28b90e37& msa=0& ll=39.368279,-101. 25& spn=132. 21796,346. 289063)

Article Sources and Contributors 7

Article Sources and ContributorsWaste-to-energy  Source: http://en.wikipedia.org/w/index.php?oldid=605175430  Contributors: A.amitkumar, Absurdist, Alan Liefting, Alansohn, Anonymi, Antandrus, Anthony Appleyard,ApostleVonColorado, Atif.t2, Auntof6, AzureFury, Beagel, Bender235, Bill william compton, Biomanuk, BorgHunter, Candleabracadabra, Chostovs, Claush66, Cvelis, Cynarplc, DASonnenfeld,Dbtbandit67, Deanlaw, DisillusionedBitterAndKnackered, Dokla007, Dosemfbek123, E8, Engineman, Falcon8765, Fiftytwo thirty, Fintan264, GGByte, Gareth Griffith-Jones, Gcc111, Gilo1969,Glane23, Globallaw, GoingBatty, Gordon1104, Gralo, Hai398, Haruth, Hmbr, Hu12, Ian Pitchford, JLMadrigal, JaGa, John, John Broughton, Jordanamb, Jumping cheese, K2T2,Khabibulinfan96, Kilmer-san, Kjkolb, Lamro, Leland Searles, M@sk, Magioladitis, Maliknj, Mauls, Melaen, Millere08, Mmberney, Mogism, NeilN, Old Moonraker, Paul john kinsella,PaulCamp, Perrma25, Pinethicket, Pragmaticstatistic, Reaper Eternal, Samward1998, Some jerk on the Internet, SteveOnline, Sunray, TeH nOmInAtOr, TettyNullus, The Thing That Should NotBe, Theimtiaz, Timelezz, Timeshifter, Ttamers, Vortexrealm, Vrenator, Walter1975, Wanless.enviro, Watisfictie, Wavelength, Whitthom, 158 anonymous edits

Image Sources, Licenses and ContributorsImage:District heating plant spittelau ssw crop1.png  Source: http://en.wikipedia.org/w/index.php?title=File:District_heating_plant_spittelau_ssw_crop1.png  License: Creative CommonsAttribution 2.5  Contributors: Croped by Gralo from a self-taken image by Contributor

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