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Waste to Energy Project in Ghana: Landfill Gas or Incineration

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Waste to Energy Project in Ghana: Landfill Gas or Incineration

  1. 1. Comparison Between Landfill Gas and Waste Incineration for Power Generation in Accra, Ghana Serwaa ANAGLATE Syawalianto RAHMAPUTRO Carlos RUIZ Prof. Luis Rojas 1
  2. 2. Outline  Accra  Objective & Scope  RETScreen  Waste Characterization  Landfill Gas  Waste Incineration  Results  Social Impact  Conclusions  Outlook 2
  3. 3. Accra, Ghana  1,800 Daily Tons of Waste  Open Dump Sites  Insufficient Waste Collection  Insufficient Power Capacity Source: www.atokd.com Source: http://raklak.wordpress.com 3
  4. 4. Objective & Scope Objective  Assess and compare landfill gas and waste incineration  Technical  Environmental  Economic  Social Impact Scope  Total Electricity Exported  GHG Emissions Reduction  Approximate Costs  Financial Summary  Pre-feasibility Level 4
  5. 5. RETScreen®  Free Software  Clean Energy Project Analysis  Inexpensive Technical and Financial Feasibility Analysis Energy Model Cost Analysis GHG Analysis Financial Summary Sensitivity & Risk Analysis 5
  6. 6. Waste Characterization 3% 3% 3% 2% 6% 17% 66% Organic Inert Paper Plastic Glass Metal Textile & Leather 6
  7. 7. Landfill Gas Source: Affiliated Engineers, 2010 7
  8. 8. Landfill Gas Simulation Amount of Waste Input Parameter Value Waste Disposal Rate (mi) 270,000 t/yr Landfill Opening Year 2014 Landfill Closing Year 2044 Generation Constant (k) 0.06 yr-1 Generation Potential (Lo) Waste Composition 170 m3/t Climatic Conditions 6MW  Assumptions:  Constant Biodegradable Fraction in Waste  50% of CH4 by Volume  75% Collection Efficiency 8
  9. 9. Waste Incineration Electricity Generation  Pretreatment  Furnace - Waste Incinerator Flue Gas Treatment Drying in the receiving pit. Source: www.sick.com Moving grate furnace is the most Boiler robust.  Energy Recovery - Low-pressure steam boiler is convenient when energy recovery is designed for electricity use only (Haukohl, J., Rand, T., & Marxen, R. ,1999)  Energy Production - Rankine cycle with steam turbine, condenser, boiler, and pump for power generation.  Flue Gas Treatment - For 600 ton to 900 ton/day: SNCR, semi-dry scrubber, activated carbon, and a bag house filter are usually used (Kuo, Lin, Chen, Tseng, & Wey, 2011). Grate Furnace Receiving Area Receiving Pit Source: www.valorena.fr 9
  10. 10. Waste Incineration Simulation Proximate AnalysisAsh Combustibles Moisture 14% Ash 31% 1 Waste Analysis WASTE INCINERATION Waste Feed Rate Dry Weight of Feed Waste 270,000 120,727.12 Feeding Rate Lower Heating Value Moisture 55% t/yr t/yr 13.78 t/hr 15.854 Ultimate Analysis 2 Fuel Potential POWER SYSTEM GJ/t Fuel Potential 218.49 Gj/hr Predefined: • Udomsri, Petrov, Martin, & Fransson, 2011 • Suggested values from RETScreen Simulation: Energy Model Combustibles 3 Power Generation Availability 8,401 hours Back Pressure 5.6 kPa Steam Temp. 380 °C Return Temp. 90 °C Steam Flow 68,600 kg/hr Operating Pressure 80 bar Turbine Efficiency 75 % Fuel Required 218 Gj/hr 10
  11. 11. Results – Energy and Environment Landfill Gas Technology Engine Power Capacity (kW) Electricity Exported (MWh/yr) Waste Incineration 6,000 16,505.24 48,000 138,658 Electricity Export Rate - $ 58.7 Source: www.engineeringnews .co.za Source: www.siemenspowergeneration.c om Technology Landfill Gas Waste Incineration Emission Factor (Kg/GJ) CO2 CH4 N 2O Annual GHG Reduction (tCO2) 0 0.0040 0.00010 273,657 29.43 0 0.00315 41,413.4 Energy Mix in Ghana: • Hydro Power 67.6% • Thermal Power 32.4%  WI energy output > 8 times that of LFG  GHG reductions are achieved in both technologies  LFG GHG reductions > 6 times that of WI 11
  12. 12. Results - Financial 25,000,000 Cost Breakdown Accumulated Landfill Gas WI CashFinancial Flow 20,000,000 Cash Flow (USD) Engineering $ 3,743,026 $ 10,455,025 $ 7,512,749 Balance of System $ 3,630,152 $ 23,679,131 Total Initial Cost $ 15,135,177 $ 34,934,905 5,000,000 Results 8.1% 4.8% Payback Period $ 1,050,000 Power System 10,000,000 WI IRR Initial Cost 15,000,000 Landfill Gas 13.2 15.9 years Annual Income $2,817,600 $8,139,215 Net Present Value (NPV) Benefit-Cost Ratio $4,612,086 $826,358 1.61 1.05 Project Year 0 1 2 3 Annual Cost 0 -5,000,000 and Debt Payment 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 -10,000,000 O&M $ 1,531,000 $ 5,460,225 Debt Payment (10 yr) $ 1,028,193 $ 2,373,267 $ 2,559,193 $ 7,833,492 $ 2,817,600 $ 8,139,215 -15,000,000 Total Annual Cost LFG Waste Incineration -20,000,000 Annual Income  Inflation Rate – 3%  Debt Interest Rate – 6%  Discount Gas rendered better profitability  Electricity Export Escalation – 2%  Landfill Rate – 4.5%  Since Ghana is a developing country, affordability is important 12
  13. 13. Social Impact  Job Creation Source: www.rvg-ghana.com  Improvement of the City’s Image  Improved Sanitation Source: Schah Fekri, 2011  Productivity Increase Source: Journalists for Human Rights, 2010 13
  14. 14. Conclusion & Outlook  Both technologies are environmentally friendly and economically feasible.  Any solution would represent a great improvement.  LFG is preferred due to its outstanding environmental performance.  WI is more suitable in case of limited space.  Risk and sensitivity analysis are recommended.  Inclusion of carbon credits should be considered.  Further on-site tests should be carried out. 14
  15. 15. Thank you. Any Questions? Pictures in cover page courtesy of: •www.treehugger.com •Graham Turner (http://www.guardian.co.uk) •www.sick.com 15

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