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. Outline
 Accra
 Objective & Scope
 RETScreen
 Waste Characterization
 Landfill Gas
 Waste Incineration
 Results
 Social Impact
 Conclusions
 Outlook
2

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. 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. 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. Waste Characterization
3%
3%
3%
2%
6%
17%
66%
Organic
Inert
Paper
Plastic
Glass
Metal
Textile & Leather
6

7. Landfill Gas
Source: Affiliated Engineers, 2010
7

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. 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. 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. 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. 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. 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. 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. Thank you.
Any Questions?
Pictures in cover page courtesy of:
•www.treehugger.com
•Graham Turner (http://www.guardian.co.uk)
•www.sick.com
15