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Waste to energy projects with reference to MSW, Sourabh Manuja, TERI, India


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This lecture is part of the 2016 ProSPER.Net Young Researchers’ School on sustainable energy for transforming lives: availability, accessibility, affordability

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Waste to energy projects with reference to MSW, Sourabh Manuja, TERI, India

  1. 1. WASTE to ENERGY PROJECTS with reference to MSW 10th February 2016 Sourabh Manuja Source:
  2. 2. Content of the presentation • Overall scenario of MSW management • Need for looking at W2E options • International status • Technology options • Financial viability • Barriers • Conclusions
  3. 3. Waste-to-energy Process of capturing energy from processing of waste, in the form of electricity or heat (Termed as Thermal and Biochemical Recovery) Source:
  4. 4. Typical MSW characteristics in Indian cities Parameter Unit Range Compostable % 30 – 55 Recyclable (Plastics, Paper, Metal, Glass etc) % 5 – 15 Inert including C&D waste % 40 - 55 Carbon/Nitrogen (C/N) Ratio 14 – 53 Moisture % 17 – 65 Calorific Value kcal/kg 520 – 3766 Source:
  5. 5. Key features of MSW management • Recyclable content of the MSW is picked up by waste pickers and send for recycling • India reports high recycling rate of 70% though most of it happens in informal sector • C&D waste presently disposed on land but can be recycled • High moisture content and low calorific value of organic fraction of Indian MSW makes it more amendable to biochemical conversion
  6. 6. Key Issues(1/2) • Growing waste quantities – MSW has increased from just 7 MTPA in 1947 to staggering amount of 62 MTPA in 2014, about 50% of which is organic waste – Industrial hazardous waste is reported to be around 6.23 MTPA of which 30% around is organic waste – Would require around 1240 hectare of land per year if landfilled. • Growing demand for power – Most of the Indian cities face peak hour power shortages due to T&D losses and increasing demand for power due to life style changes • Indifferent supply situation of fossil fuels – Limited crude resources
  7. 7. Key Issues(2/2) • Change in waste composition, increasing quantities of packaging waste, 40-50% of organics in waste stream • General apathy of local bodies and public to deal with the issues related to management of MSW • This problem can be addressed to extent by adopting W2E technologies to maximize processing of waste which goes to sanitary landfill for disposal • This is also in compliance with MSW Rules 2000
  8. 8. Problem in adopting W2E • There is however problems in adopting W2E technologies to MSW – Variability in composition – High moisture content – Can cause fouling of equipment if inerts are high – Use of unsegregated waste can also lead to emission of toxic heavy metals • Need for improvement in present waste management practices
  9. 9. Impetus • NEP, 2006 and NAPCC, 2008 also give emphasis to – Need for W2E projects – Need for indigenous development and customization of W2E technology
  10. 10. W2E – International status • Around 600 facilities processing around 130 MTPA of waste • The focus is to move away from landfilling and maximize resource recovery including energy generation Source: %20Around%20the%20World%202009-L.jpg
  11. 11. Available Technology options – Landfilling with gas recovery – Incineration – RDF based power generation – AFR (Alternate Fuel and Raw Material) – Biomethanation process – Pyrolysis/gasification – Plasma arc pyrolysis
  12. 12. Disposal in landfills Source:
  13. 13. Key features • Biodegradable waste is deposited in a landfill which slowly decomposes leading to landfill gas production that can be used to power engines, turbines or vehicles • Advantages: – Low cost energy recovery due to scale economies – Controlled LFG recovers high percentage of total gas potential • Disadvantages – Uncontrolled, methane gas easily escapes – Requires significant landfill infrastructure – Requires very high volumes of waste and large land areas • As per MSW 2000 rules, however, biodegradables cannot be disposed off to landfills
  14. 14. 14 Pilot demonstration of clean technology for LFG recovery from Okhla disposal site
  15. 15. Study objectives • Objective of this pilot demonstration was to capture and purify LFG currently being emitted from Okhla waste disposal site by using Clean Technology (CT) and thereby utilize the energy and reduce the risk of uncontrolled methane emissions 15
  16. 16. Status in India • Uncontrolled methane emission from MSW disposal sites are potential source of GHG emission • There are close to 5100 cities and towns in the country each having atleast one (mostly two) such sites which are such source of such emissions • Such landfill once they reach their capacities will have to be closed and redeveloped into alternative post closure land use • Efforts worldwide to tackle the problem have focused on gainful recovery of methane as potential energy source • In India, as on date, no pilot was demonstrated in field conditions based on actual site data
  17. 17. Status of disposal sites in Delhi • Delhi generates around 7000 TPD of municipal waste • The waste is presently disposed in three disposal sites – Okhla – Bhalaswa – Ghazipur • All the three disposal sites have reached their capacities and due for closure 17 Description Okhla Ghazi pur Bhalaswa East West Start Year 1996 1984 1992 1998 Estimated closure year 2007 2008 2007 2007 Total MSW disposal by end 2006 (million tonnes) 4.14 6.93 5.39 1.52 Current disposal rate (tonnes/day) 1200 2000 2400 800 Area for disposal (ha) 16.9 29.6 26.2 9.2
  18. 18. LFG potential for Delhi 18 S. No. Location of landfill in India LFG Recovery (m3 hr-1 ) Projected LFG To Energy Potential Reference 1. Okhla Landfill, New Delhi 1,522 2.7 to 1.9 MW for 10 years IRADe/ USEPA (2009)/MCD 2. Okhla Landfill, New Delhi 1,660 0.8 to 1.0 MW for 10 years SCS Engineers/USEPA (2007) 3. Bhalswa Landfill, Delhi 2,400 3.7 to 2.6 MW for 10 years USEPA (2009)/MCD 4. Ghazipur Landfill, Delhi 2,700 2.0 to 1.8 MW for 10 years USEPA (2009)/MCD 5. Ghazipur Landfill, Delhi 1,200 8.8 MW GAIL/SENES (2012)
  19. 19. Why Okhla site? • The disposal site has suitable flat terrain available for setting up pilot; accessibility of borewell drilling apparatus not a problem at site • Waste disposal history of around 12 years • Suitable depth (average 30 m) available for possible LFG generation and recovery • Densely populated residential areas towards Eastern and Southern sides of the landfill – Possible users of the LFG – Site therefore needs to be closed and rehabilitated urgently • Proposed laboratory for environmental monitoring to be set up at JMIU which is close to the site
  20. 20. Google earth view Site for pilot
  21. 21. Flow sheet for basic LFG extraction
  22. 22. Graphical representation
  23. 23. Pilot instrumentation
  24. 24. LFG extraction Gas well
  25. 25. Network of gas wells
  26. 26. Results of static measurements
  27. 27. Summary of static monitoring   CH4 (%) CO2 (%) O2 (%) H2S (%) Balance (%) PLFG (Millibar) Maximum 54.2 22.0 2.2 0.9 38.2 0.9 Minimum 27.7 7.7 0.5 0.1 4.5 -0.4 Average 44.6 15.9 1.1 0.8 26.6 0.2
  28. 28. Dynamic monitoring of LFG
  29. 29. Summary of dynamic monitoring   CH4 (%) CO2 (%) O2 (%) H2S (ppm) Balance (%) PLFG (Millibar) TLFG (0 C) QLFG Max 58.3 23.3 15.3 >500 57.1 28.1 41.0 31.5 Min 20.2 8.1 1.4 >500 19.5 -32.5 21.1 5.84 Average 43.3 16.9 5.7 >500 34.0 -17.0 34.5 19.6
  30. 30. LFG Modeling Results • Under aggressive conditions for the year 2012 = 5447 m3 /hr • Under conservative conditions for the year 2012 = 2723 m3 /hr
  31. 31. Economic benefits • Thermal – For drying landfill leachate – As cooking fuel or fuel for boiler, furnace or kilns in the neghbourhood – Space heating • Power generation if the grid for evacuation is available • Further purification and use as transportation fuel
  32. 32. Environmental benefits • Prevents uncontrolled emission of GHG • No adverse health impacts on sanitary workers and waste pickers working at disposal sites and nearby residential population • Reduces fire and explosion hazards at landfills
  33. 33. Conclusions • Uncontrolled LFG emission from disposal sites is a national problem which needs to be addressed • LFG harvesting during closure of disposal sites not only stabilises it but also provides energy for neighbourhood usage • Proper closure with provision of impermeable cover is desirable before LFG harvesting • Ministry should request GAIL to prepare a master plan for harvesting LFG from such uncontrolled dumps • CPCB needs to take up the matter with concerned ULBs to facilitate the process 34
  34. 34. Incineration Source:
  35. 35. Incineration MSW Drying Segregation Heat Flue gas Incineration Pelletisation (optional) Fuel, binder Ash Fuel
  36. 36. Key features • Direct burning of wastes in the presence of excess air at high temperatures liberates heat energy, inert gases and ash. • Advantages: – Most suitable for high calorific value waste (paper, plastics, wood) – Relatively free of noise and odor; requires small land area • Disadvantages: – Low heating value waste -not ideal for energy recovery – Toxic metals/PVC lead to increased air emissions – High capital and O&M costs
  37. 37. AFR Source:
  38. 38. Waste combustion in cement kilns • Alternatively waste can be used as fuel to substitute tradition fuel in cement kiln • Advantages – Supplements traditional fuel – Waste treatment is achieved • Disadvantages – High level of chlorides is not acceptable – Distance over which waste can be transported is also limiting factor
  39. 39. Co-combustion in cement kilns
  40. 40. Refuse Derived Fuel MSW Drying Segregation Steam Flue gas Boiler PelletisationFuel, binder Ash Turbine
  41. 41. content/uploads/2015/09/Subcoal-NP.jpg
  42. 42. MSW palletization plant at Hyderabad (courtesy MNRE)
  43. 43. Key features • Segregating, crushing and drying of organic material from MSW into dense and solid fuel pellets that can be used as main or supplementary fuel for industrial boilers • Advantages: – High energy content – Convenient for storage and transport • Disadvantages: – High energy consumption for crushing and drying – Inorganic content tends to reduce effectiveness – Only conducive during periods of lower rainfall – May require gas cleanup to avoid air emissions
  44. 44. Suitability of different W2E option for India (1/3) Technology Advantages Disadvantages Applicability for India Landfill with LFG extraction Low cost energy recovery Controlled, high recovery Uncontrolled gas can escape Requires significant landfill infrastructure Requires high volume of waste and large land area Not recommneded as MSW Rules 2000 prohibit disposal of organic waste at landfill Incineration More suitable for high calorific waste like paper wood and plastics Relatively free from noise, odour and require less land area Capital intensive Low heating value waste not suited Toxic metals and chlorinated plastics lead to pollution Requires high O&M Cost Not recommended unless waste stream is supplemented by high calorific value waste free from chlorinated plastics
  45. 45. Suitability of different W2E option for India(2/3) Technology Advantages Disadvantages Applicability for India Biomethanation Can be small scale with no external power source required Totally enclosed, modular construction possible Odour and visible pollution reduced Capital intensive Requires high degree of easily biodegradable material Recommended only with segregated MSW RDF burning Fuel produced has high energy content Fuel is convenient to store and transport High energy use in crushing and drying of waste High inorganic content reduces effectiveness of fuel Recommended if the waste is free from chlorinated chemicals
  46. 46. Suitability of different W2E option for India(3/3) Technology Advantages Disadvantages Applicability for India Gasification/pyrolysis Can be small scale with modular design Closed system with no smell or odour Less expensive gas clean system than incinerators Net energy recovery might of affected by moisture No commercial model on MSW as yet Technology adaptation for MSW feedstock required, therefore not recommended
  47. 47. Experience in India so far(1/4) As per information available for 2012, compiled by CPCB, municipal authorities have so far only set up 279 compost plants, 172 biomethanation plants, 29 RDF plants and eight Waste to Energy (W to E) plants in the country. •RDF – Initially RDF plants were installed in India in the mid-nineties followed by larger ones later: – 5 TPD plant in Bangalore (private entrepreneur) – MSW to pellets – 80 TPD plant in Mumbai (1994, DST) – MSW to pellets – 200 TPD plant in Hyderabad – MSW to pellets (1999, DST Technology), private company (SELCO) upgraded to 1000 TPD with power generation
  48. 48. Experience in India so far…(2/4) – RDF plant in Vijaywada (fluff) along with pelletization plant at Guntur, pellets transported to Vijaywada followed by combined power generation – 5 MW power generation capacity, BOT operator (DST technology) – RDF plant in Jaipur (fluff), BOT operator, baled fluff sent to cement plant for CDM benefits (500 TPD capacity) – RDF plant in Chandigarh (fluff) – Un-operational, BOT operator, baled fluff sent to cement plant for CDM benefits (500 TPD capacity)
  49. 49. Experience in India so far (3/4) • Biomethanation – Plant in Pune (pilot plant) using technology from Paques (5 TPD capacity) – mid nineties (closed) – Plant in Vijaywada using segregated MSW (16 TPD) and slaughterhouse waste (4 TPD), technology from Mailhem, Pune – Plant in Chennai (Koyembedu flower market) of 30 TPD capacity, BIMA technology, Austria – Plant in Lucknow, 5 MW designed capacity, 500 TPD MSW input (closed)
  50. 50. Experience in India so far (4/4) Harnessing of biogas (landfill gas) from landfills (dumpsites) – Attempted in Delhi by DEDA in a small scale – Large scale closure and harnessing of landfill gas under construction at Gorai in Mumbai – Similar closure and landfill gas harnessing plans for two other sites in Mumbai (Deonar and Mulund) – Plans under way for Delhi – A number of Municipal Corporations have floated bids for such projects in the recent past
  51. 51. Issues in W2E technologies • Competing technologies, particularly composting • The emphasis is on ‘royalty’ rather than ‘tipping fee’ • The technology with lower capital outlay and higher overall revenue accrual is preferred
  52. 52. Need for the sector • The need of different site situations have to be thoroughly analyzed and solutions have to be accordingly designed • E.g. in case of close proximity of habitation, open windrow composting would not be the preferred option in spite of cost advantage • W2E and in-vessel composting would then be the competing technologies
  53. 53. Need for the sector… • Integrated facilities are gradually coming into consideration • E.g. a combination of aerobic windrow composting and RDF such attempts at Rajkot and Delhi • Decentralized facilities based on dedicated waste stream (Vijaywada, Chennai, TEAM process of TERI)
  54. 54. Financial assessment of options • High rate AD must be considered a high priority for wet organic waste • RDF based power generation from already existing or dedicated boiler holds promise and the option is commercially available; this would be attractive especially when it is expected that packaging waste in going to increase in future • Gasification/pyrolysis has a distinct promise, and although there are limitations to its uptake, these can be circumvented as the technology matures • The present trend is in favour of material recovery facilities and a shift away from landfills for MSW disposal. LFG recovery also not favoured by MSW Rules
  55. 55. Financial cost estimation • Biomethanation and RDF options considered for detailed financial analysis as these have been working/tried in India • Three scenarios considered for biomethanation option – 300 TPD (3 MW) – 500 TPD (5 MW) – 1000 TPD (10 MW) • One scenario considered for RDF option – 700 TPD (6.5 MW)
  56. 56. Inputs and assumptions Inputs Units Biomethanation RDF Plant capacity MW 3 5 10 6.5 Waste processed TPD 300 500 1000 700 Life of plant Years 15 15 15 15 Land reqd. m2 /Tonne 175 175 175 200 Capital cost Rs. Cr. 40.25 57.3 102.0 60.0 Land cost Rs. Cr. 0.3 0.5 0.6 0.4 O&M Rs. Cr. 2.72 4.13 8.25 3.0 Annual escalation in O&M % 4.83 4.83 4.83 4.83 Debt-Equity ratio Ratio 70:30 70:30 70:30 70:30 Interest rate % 12 12 12 12 Note: 1 crore is 10 million
  57. 57. Inputs and assumptions… Inputs Units Biomethanation RDF Repayment period (including 1 yr moratorium) Years 10 10 10 10 Return on equity % 14 14 14 14 Discount rate % 12.6 12.6 12.6 12.6 Capital recovery factor % 15.2 15.2 15.2 15.2 Source: National Master Plan for W2E Plants, MNRE and TERI Estimates
  58. 58. Estimation of annual generation Particulars Units Biomethanation RDF Plant capacity MW 3 5 10 6.5 Parasitic consumption MW 0.45 0.75 1.50 1.00 Net electricity for sale MW 2.45 4.08 8.16 5.25 Annual hours of generation Hours 7920 7920 7920 6132* Annual generation MU 20.20 33.66 67.32 33.73 Source: National Master Plan for W2E Plants, MNRE and TERI Estimates
  59. 59. Levelised unit cost of electricity generation Technol ogy option Plat capacity Annutis ed Capital cost O&M Fuel cost Less sale of by product Net levelise d cost LUCE Unit MW Rs/Cr Rs/Cr Rs/Cr Rs/Cr Rs/Cr Rs/kWh Biometh anation 3 0.76 2.85 2.48 2.48 3.61 1.79 5 1.09 4.32 7.84 4.13 9.12 2.71 10 1.92 8.64 22.28 8.25 24.58 3.65 RDF 6.5 1.13 3.14 9.16 Nil 13.43 3.98 Source: TERI Estimates
  60. 60. Viability gap analysis Technology Plant capacity LUCE of MSW Benchmark tariff Viability gap Units MW Rs/kWh Rs/kWh Rs/kWh Biomethanati on 3 1.79 3.14 (1.35) 5 2.71 3.14 (0.43) 10 3.65 3.14 0.51 RDF 6.5 3.98 3.14 0.84 Source: TERI Estimates
  61. 61. Role of CER to cover Viability gap Technology Plant capacit y Viability gap Additional revenues from CERs Viability gap after CERs Units MW Rs/kWh Rs Crores Rs/kWh Biomethanati on 3 (1.35) 2.00 (2.34) 5 (0.43) 3.34 (1.42) 10 0.51 6.68 (0.48) RDF 6.5 0.84 3.35 (0.15) Source: TERI Estimates
  62. 62. Proposed flow for 500 TPD city Generators Waste processing AD (250 TPD) 1.25 MW RDF (100 TPD) 1 MW Ragpickers D2D Collection Kabadiwala 50 TPD from Ragpickers 50 TPD direct Residue to landfill
  63. 63. National waste inventory database for W2E • As per estimates of CPCB, 31 larger cities in the country generate around 36000 TPD of MSW • This can generate around 36000 MW (2500 MW as per MNRE) of power • In addition, it is estimated that around 180 TPD of slaughter house waste and 1800 TPD fruit and vegetable market waste would generate around 3600 MW and 21000 MW of power, respectively • This can substantially improve viability of MSW based W2E projects
  64. 64. Impacts on livelihood of ragpickers • In most cities, around 10-15% of waste is removed from city streets by ragpickers • Large unorganized work force in the cities • If the paper and plastic waste collected by them can be diverted to W2E projects, it will make them financially more attractive • The ragpickers can be formally inducted by local bodies/NGOs/private operators for doorstep collection of recyclables and organic waste • This would not only protect their livelihood but also enhance their income
  65. 65. Barriers • Technical barriers • Incineration well researched but because of high capital cost and emissions, not in use in India • Other processes like pyrolysis and gasification need more work on making the product available at commercial level • Non technical barriers • Unavailability of source segregated waste • Higher cost of energy generation –High cost incurred on pollution control in thermochemical process –Poor management record of operations in India
  66. 66. Barriers… • Non-technical barriers – Lack of public acceptance – Due to negative perception of such projects – Focus on material recovery and recycling as compared to W2E – Poor construction practices and workmanship in India
  67. 67. Barriers… • Need to supplement MSW with other waste streams like paper, plastic, biomass as it is heterogeneous • ESCOs perceive failure/payment as risks for the project developers setting up such projects and therefore are not willing to take up municipal projects for financial considerations
  68. 68. Conclusions • MSW based W2E options can not only reduce the pressure on landfills but also can be source on power • High rate biomethanation system and RDF based power generation are attractive options and technologies are commercially available • Incinerator is not favored due to high capital and O&M costs and possible emission of toxics • Use of LFG is also not favored as this is not compliant with MSW Rules
  69. 69. Conclusions… • It is proposed that the project developer also carries out C&T as W2E projects are sensitive to level of waste segregation • Viability gap is nil or negligible in case of high capacity Biomethanation plants and RDF plants • Availing funds under CDM benefits through CERs, viability gap is fully met in all cases • Diversion of vegetable and fruit market wastes and slaughter houses waste improves project viability of W2E options
  70. 70. Recommendations • Integrated model of MSW management would be useful for W2E projects • Involving ragpickers in door step collection of segregated waste would protect their livelihood • For RDF projects, it is suggested that fuel preparation is done in semi-mechanized/ decentralized manner at lower cost and power generation in centralized manner to reduce the cost of setting up the project
  71. 71. Thank you
  72. 72. Schematic diagram of TEAM
  73. 73. TEAM Process (acidification) Startup of acidification process Drying of digested sludge for manure production