International Journal of Computer and Information System (IJCIS) Peer Reviewed - International Journal Vol : Vol.
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php/ijcis/index Techno-Economic Feasibility Analysis of Waste-to-Energy Power Plant Based on Anaerobic Digestion: A Case Study on Sabira Island Saskia Saraswati Harahap, 2Iwa Garniwa Departement of Electrical Engineering.
Faculty of Engineering University of Indonesia Depok.
Indonesia Email: 1saskia.
saraswati@ui.
id, 2iwa@eng.
AbstractAiThis study explores the techno-economic feasibility of establishing a small-scale waste-to-energy (WTE) power plant using anaerobic digestion technology on Sabira Island, one of the outermost islands of Jakarta.
Indonesia.
As an isolated area with limited energy access and increasing organic waste generationAiestimated at around 1 to 1.
2 tons per dayAiSabira presents both an environmental challenge and a renewable energy opportunity.
Through the conversion of organic waste into biogas, which can then be used to generate electricity, this project seeks to address waste management issues while contributing to sustainable energy production in remote regions.
A comprehensive techno-economic analysis was conducted, incorporating factors such as capital and operational costs, biogas yield potential, energy conversion efficiency, and local electricity pricing.
Two different electricity selling price scenarios were evaluated to determine financial viability.
The results show that under the first pricing scheme, the project fails to meet the minimum return expectations, whereas the second scenario demonstrates acceptable economic performance, suggesting that the project can be considered feasible if more favorable electricity tariffs are adopted.
The study concludes that successful implementation of such a WTE system would depend not only on technical and economic parameters but also on supportive policy frameworks, appropriate pricing mechanisms, and access to clean energy financing.
The findings offer valuable insights for policymakers and stakeholders aiming to promote decentralized renewable energy solutions in IndonesiaAos remote islands.
Keywords : Waste for Energy.
Electrical.
Anaerobic Digestion.
Renewable Energy INTRODUCTION Indonesia, as one of the worldAos largest archipelagic nations, faces a unique set of challenges in providing reliable electricity and sustainable waste management solutions to its outer and remote islands.
Sabira Island, located at the northernmost part of JakartaAos Thousand Islands Regency, is a small but inhabited island that exemplifies these dual issues.
Due to limited access to centralized waste processing and electricity infrastructure, the local community relies heavily on diesel generators (PLTD) for power and often resorts to open burning for waste disposal.
These practices not only burden the environment but also pose health and sustainability risks.
In recent years, the Indonesian government has promoted the development of renewable energy sources such as solar photovoltaic systems (PLTS).
However, on islands like Sabira.
PLTS alone is often insufficient due to intermittent generation and limited energy storage capacity, especially during cloudy or Journal IJCIS homepage - https://ijcis.
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php/ijcis/index rainy seasons.
Moreover, the increasing electricity demand continues to outpace the supply capabilities of existing systems.
As such, there is a critical need for complementary and more resilient energy sources that can operate independently of weather conditions.
At the same time, the substantial proportion of organic waste generated daily on Sabira Island estimated between 1 to 1.
2 tons per day presents an untapped opportunity for local energy generation.
Waste-to-energy (WtE) technologies, particularly anaerobic digestion (AD),.
offer a viable pathway to address both energy and environmental challenges in one integrated solution.
Anaerobic digestion is a biological process that converts organic waste into biogas, primarily methane, which can be used as a fuel for electricity generation.
This study explores the feasibility of implementing a small-scale WtE power plant based on anaerobic digestion technology in Sabira Island.
The research focuses on evaluating the technical potential of local Page 151 International Journal of Computer and Information System (IJCIS) Peer Reviewed - International Journal Vol : Vol.
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php/ijcis/index organic waste as a feedstock and analyzing the economic viability of the project under two electricity pricing scenarios.
The goal is to determine whether PLTSa-AD can serve as a sustainable and replicable model for remote island communities across Indonesia.
The anaerobic digestion process occurs in methanogenesis culminating in the production of methane-rich biogas.
The key parameter that determines biogas yield is the amount of Volatile Solid (VS) content within the Total Solid (TS) fraction of organic waste.
Total Solid (TS) refers to the dry matter in the organic waste .
n % of feedstock Volatile Solid (VS) is the combustible portion of TS, and directly contributes to methane production.
a parameter that is directly related to the amount of electrical energy, while other gases are not related to the process, the amount of methane produced based on the amount of volatile solid (VS) for 1 kg of organic waste mixture is as in the following table (K.
Muthupandi.
March Table 2.
Biogas Calculation Biogass Production .
3 / har.
VBS
(%)
Biogas Productionn (M3/Kg TS) 0,676 Reference Tanya McDonald.
Gopal Achari and Abimbola Abiola Article Feasibility of from the codigestion municipal and agro-industrial wastes in rural communities.
Muthupandi.
March 2.
Economic analysis in planning the construction of PLTSa with Anaerobic Digestion technology is very important, because it is closely related to the economic feasibility of the project.
Table 1 TS and VS Calculation (%) Reference Engineering Economics is a process related to methods that allow someone to make economic decisions to minimize costs and or maximize benefits for business organizations on technical problems (Panneerselvam, 2.
In order for the target of engineering economics to be achieved, the solution provided must show a positive benefit to long-term costs.
addition, the solution provided must also show the sustainability of an organization from the idea to the expected technology.
According to Frear et al.
(Washington State University, 2.
, the estimation of biogas and methane production from organic waste in an anaerobic digester can be modeled through the following formulas:
types of (K.
Organic Total Gas Metane (%) Life Cycle Cost Life Cycle Cost(LCC) is an approach in economic analysis that calculates the total costs that will arise during the life of a project.
LCC = EC IC SV NFOMC NRC RC .
To calculate the amount of potential electrical energy produced in an anaerobic digestion process, the amount of methane gas is Journal IJCIS homepage - https://ijcis.
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php/ijcis/index Where:
LCC:present valuefrom LCC value : present valuefrom energy costs IC : present valuefrom investment costs SV : present valuefrom the value of the asset after use .
NFOMC: present value of operating costs and repair costs that recur each year Page 152 International Journal of Computer and Information System (IJCIS) Peer Reviewed - International Journal Vol : Vol.
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php/ijcis/index NRC: present valuefrom operational costs and repair costs that do not recur every year yaycIycI = ycn1 [ RC : present valuefrom other costs ycAycEycO1 cn Oe ycn1 )] ycAycEycO1 Oe ycAycEycO2 2 Where :
Cost of Energy Cost of energy (COE) is a comparison between the total cost per year of the system with the energy produced during the same .
yaycCya : interest value that produces a positive NPV value : interest value that produces negative NPV NPV1 : positive NPV value yayaya ycU yaycIya ycNycuycycayco yaycuyceycyciycn ycycaycuyci yccycnEaycaycycnycoycoycaycu .
coycOE.
NPV2 : negative NPV value Net Present Value NPV is a parameter that uses a relevant interest Where:
rate to calculate the difference between the present COE: Cost of Energy value of total investment and the present value of LCC:Life Cycle Cost value or life cycle cost total revenue during the operational period.
ycu CRF: Cost Recovery Factor NPV =Oc yaAycu =yaycu .
ycu yc=ycu .
Where :
Levelized Cost of Energy Levelized Cost of energy (LCOE) is used to assess how much it costs a system to produce power per unit of time.
ya ycC ycA ya Ocycuyc=1 yc yayaycCya = yc yc .
yc yayc Ocycuyc=1 .
yc :receipts in year n : totalinvestment costs in year n : timeoperating system .
:interest rate per year (%) yc II.
RESEARCH METHODS
Where:
It : investment cost in year t Ot : operating cost in year t Mt : maintenance cost in year t Ft : fuel cost .
f an.
in year t Et : energy produced .
in year t r : discount rate .
nterest rat.
n : project life .
n year.
Internal Rate of Return Internal Rate of Return (IRR) is a financial measure that shows the rate of return of an investment project.
IRR is calculated based on cash inflows and outflows that occur during the life of the project and is technically defined as the discount rate at which the net value of the cash flows becomes zero.
The study uses field surveys to estimate daily waste volume and composition.
Techno-economic modeling includes: Total Solid (TS) and Volatile Solid (VS) content biogas yield, and methane The economic analysis applies two tariff scenarios over a 25-year project life using NPV.
IRR, and DPP metrics.
The system design assumes integration with existing PLTS and PLTD infrastructure on Sabira Island.
RESULT AND ANALYSIS
Based on waste generation data.
Sabira Island produces approximately 1 to 1.
2 tons of waste per day, with organic waste dominating the composition at 83.
35%, and the remaining 16.
consisting of non-organic materials and other Journal IJCIS homepage - https://ijcis.
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php/ijcis/index Table 3.
Presentage of Waste Amount Type of waste Organic Non-Organic Presentage (%) 83,35% 16,65% 324,921 240,7665 162,7581 97,65488 0,91112 411,899 305,2172 206,3268 123,7961 1,155017 445,416 330,0533 223,116 133,8696 1,249003 339,048 251,2346 169,8346 101,9007 0,950734 8150,55 5509,772 3305,863 30,8437 average/day (MW) 0,994958 From this volume, the average daily Total Solid total energy 1 year (MW) 363,1597 (TS) content is estimated at 336.
58 kg, with Volatile Solid (VS) content reaching 249.
4 kg per These VS materials can be converted into Based on the table above, it can be concluded biogas with an estimated volume of 168.
6 kg/day, that in one day it produces an average of 0.
which in turn contains approximately 101.
16 MW of electrical energy.
In one year, the electrical kg/day of methane gas (CHCE).
The energy potential energy that can be produced is 363.
15 MW
of this methane is equivalent to approximately Waste and Energy Graph 9944 MWh/day of electricity.
Table 4.
Energy Calculation Daily Garb
Pile
,7%*
Total Garbage Pil.
kg/day .
,1%* TS), kg/day VBS
,6%*V
S), kg/day VGM
%*VB
S) kg/day (VGM*9,3 9/1x10^.
MWh
338,494
250,8241
169,5571
101,7342
0,94918
340,433
252,2609
170,5283
102,317
0,954618
333,508
247,1294
167,0595
100,2357
0,935199
326,306
241,7927
163,4519
98,07114
0,915004
353,729
262,1132
177,1885
106,3131
0,991901
310,517
230,0931
155,5429
93,32576
0,870729
364,532
270,1182
182,5999
109,5599
1,022194
353,175
261,7027
176,911
106,1466
0,990348
307,193
227,63
153,8779
92,32673
0,861408
350,128
259,4448
175,3847
105,2308
0,981804
322,428
238,9191
161,5093
96,90561
0,904129
311,071
230,5036
155,8204
93,49226
0,872283
483,642
358,3787
242,264
145,3584
1,356194
341,264
252,8766
170,9446
102,5668
0,956948
426,026
315,6853
213,4032
128,0419
1,194631
343,757
254,7239
172,1934
103,316
0,963939
233,511
173,0317
116,9694
70,18164
0,654795
409,129
303,1646
204,9393
122,9636
1,14725
320,766
237,6876
160,6768
96,40609
0,899469
372,842
276,2759
186,7625
112,0575
1,045497
374,227
277,3022
187,4563
112,4738
1,04938
317,719
235,4298
159,1505
95,49032
416,608
308,7065
208,6856
339,602
251,6451
376,166
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31
Timbunan Sampah Harian E (VGM) kWh Figure 1.
Waste and Energy Graph Referring to Article 5 of Presidential Regulation of the Republic of Indonesia Number 112 of 2022(Presidential Regulation of the Republic of Indonesia Number 112 of 2022, 2.
, it is stated that the purchase price of electricity from power plants that utilize renewable energy sources is listed in the table below, taking into account the location factor (F).
The purchase price of electricity from Waste Power Plants (PLTS.
with land provided by the government .
xcluding battery facilities or other electrical energy storage Table 5.
Energy Selling Price Determination Regulation Capacity 0 Ae 1 MW
0,890925
125,2114
1,168222
170,1121
102,0672
0,952287
278,739
188,4276
113,0565
1,054818
338,217
250,6188
169,4183
101,651
0,948404
>1 MW Ae 3
> 3 MW Ae 5
>5 MW Ae 10
>10 MW
373,119
276,4812
186,9013
112,1408
1,046273
Journal IJCIS homepage - https://ijcis.
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php/ijcis/index Highest Benchmark Price (USD cents/kW.
Years 1 Ae Year 11 Ae 30 (Max.
F)*
F)*
F)*
F)*
F)*
Page 154 International Journal of Computer and Information System (IJCIS) Peer Reviewed - International Journal Vol : Vol.
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php/ijcis/index After setting the energy price based on the regulation above, because the generating capacity of the PLTS on Sabira Island is less than 1 MW, then we can determine the energy price with the equation in column 1, using the F factor in the Java.
Madura.
Bali (Small Island.
region with an F value of 1.
With a dollar exchange rate of Rp.
16,454, it can be calculated in the equation below.
In years 1 Ae 10:
= 10,18 ycu ya The initial investment cost consists of the cost of procuring the main system, installation, construction, and supporting components.
The following estimate refers to a small-scale PLTSa project .
-80 K.
commonly used in remote areas, in this case the initial investment value for the construction of PLTSa anaerobic digestion technology is assumed to be 4 billion Rupiah and the Operational and Maintenance Cost Estimation is Rp.
000, this evaluation uses several important indicator as below Table 7.
Economic and Social Parameter = ycIycy 1.
850,47/ycoycOEa Aspect
MARR
Lifetime Depreciation Period Depreciation Cost Income Tax Inflation In years 11 Ae 25:
= 6,11
= ycIycy 1.
099,68/ycoycOEa A Unit 25 Years 25 Years Rp144,000,000 / Year Sales Scheme I And with capital structure and financing Based on electricity sales data on Sabira Island, electricity sales per kWh are Rp.
1,522/kWh.
So, based on this price, the energy price in the 1st to 10th year is set at Rp.
1,522/kWh and in the 11th to 25th year it is 1099.
Based on the calculation of energy that can be produced in Table 4.
5 and the selling price determined by sales data on Sabira Island, then with the energy capacity generated for 25 years is 15 MW/Year.
Then the income from the 1st to the 10th year is Rp.
5,527,291,134.
78 and the income in the 11th to the 25th year is Rp.
5,986,688,196.
Table 6.
Energy Income and Prices I Aspect Table 8.
Capital Structure and Financing Aspect Unit Equity Share Debt Share Net Equity Net Debt Loan Payback Time Loan Interest Rate Rp1,200,000,000 Rp2,800,000,000 20 Years 50% / Year As presented in table we get value of the LCC.
LCOE.
COE.
IRR and NPV Table 9.
Investment Feasibility Result Scheme I Unit Mark Electricity production .
MWh/Year Aspect Unit Energy cost sold .
Rp1,522 Energy costs sold .
Income year 1-10 Income year 11-25 Rp1099.
Rp.
5,527,291,134.
Rp.
5,986,688,196.
Salvage Value Tipping fee Rp.
400,000,000
Rp.
81,525,487.
NPV (Net Present Valu.
Rp/kWh IRR (Internal Rate of Retur.
Rp/kWh DPP (Discounted Payback Perio.
Rp/Year LCOE Rp/Year COE Rp2,502,763,886 Rp 1.
Rp 768,26 Rp/Year Journal IJCIS homepage - https://ijcis.
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php/ijcis/index Table 11.
Investment and Feasibility Result Scheme II Arus Kas Aspect Unit NPV (Net Present Valu.
IRR (Internal Rate of Retur.
DPP (Discounted Payback Perio.
LCOE
COE
Rp3,906,962,974 11 years Rp.
997,19
Rp.
Rp4.
Rp2.
Rp0
1 3 5 7 9 11 13 15 17 19 21 23 25
-Rp2.
-Rp4.
-Rp6.
Arus Kas Figure 2.
Cash Flow Graph Scheme I Based on this sales scheme, the project is not financially viable based on MARR, because it means the project generates more money than the investment value but does not meet the minimum expected return required to cover the risk, cost of capital and other investment alternatives.
Rp6.
Rp4.
Rp2.
Rp0 -Rp2.
1 3 5 7 9 11 13 15 17 19 21 23 25
-Rp4.
A Sales Scheme II -Rp6.
Based on the calculation of the maximum value of electricity sales set at 4.
So, based on Figure 3.
Cash Flow Graph Scheme II this price, the energy price in the 1st to 10th year Based on this sales scheme, the project is is set at Rp1,850.
47/kWh and in the 11th to 25th financially viable based on MARR, because it means year it is 1099.
kWh.
the project generates more money than the investment Table 10.
Energy Income and Prices II value and also meets the minimum expected return required to cover the risk, capital costs and other Aspect Cost Mark investment alternatives.
Electricity production .
Energy cost sold
Energy costs sold
Income year 1-10
363,159
MWh/Year Rp1,850.
Rp/kWh VI.
CONCLUSION
Simulations show that borrowing costs play a major role in determining the financial feasibility Rp1099.
Rp/kWh of a PLTSa project.
The use of low-interest Rp.
6,720,161,909.
45 Rp/Year financing schemes such as green financing, grant Income year 11-25 Rp.
5,986,688,195.
91 Rp/Year contributions, or KPBU (Government Cooperation Salvage Value Rp.
400,000,000
and Business Entit.
schemes will make the project more attractive to investors and Tipping fee Rp.
81,525,487.
Rp/Year economically feasible.
In addition, renewable energy policies from the government .
or example.
By using the investment value, operational and special feed-in tariffs for green energy subsidie.
maintenance cost value.
MARR value, inflation are highly recommended to support the value, interest rate and the same loan term, we get implementation of similar projects in remote areas.
the valueas presented in Tables 11 as below The results of the economic analysis of the waste-to-energy power plant (PLTS.
system based on anaerobic digestion technology on Sabira Island show that this project has high strategic value from the social, environmental, and energy Journal IJCIS homepage - https://ijcis.
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php/ijcis/index security aspects, although from a purely financial aspect the project is not yet fully profitable without additional support or a subsidy scheme.
REFERENCES