Socio-Environmental Analysis
Jaka Isgiyarta 1,*, Bambang Sudarmanta 2, Jalu Aji Prakoso 3, Eka Nur Jannah 4 and Arif Rahman Saleh 5,*
1 Department of Accounting, Faculty of Economics and Business, Diponegoro University, 50275 Semarang, Indonesia
2 Department of Mechanical Engineering, Faculty of Engineering, Institut Teknologi Sepuluh Nopember, 60111 Surabaya, Indonesia; [email protected]
3 Department of Economic Development, Faculty of Economics, Universitas Tidar, 56116 Magelang, Indone- sia; [email protected]
4 Department of Agrotechnology, Faculty of Agriculture, Universitas Tidar, 56116 Magelang, Indonesia;
5 Department of Mechanical Engineering, Faculty of Engineering, Universitas Tidar, 56116 Magelang, Indone- sia
* Correspondence: [email protected] (J.I.); [email protected] (A.R.S.)
Abstract: The utilization of new and renewable energy sources explicitly based on biomass needs to be increased to reduce dependence on fossil fuels. One of the potential biomasses of plantation waste in Indonesia that can be utilized is oil palm plantation waste in the form of fronds and trunks that are converted with multi-stage downdraft gasification technology. This study aimed to conduct a technical analysis, economic analysis, investment risk analysis, social analysis, and an environ- mental impact assessment of power plants fueled by oil palm plantation waste. The method used was the upscaling of a prototype of a 10 kW power plant to 100 kW. The results showed that it was technically and economically feasible to apply. The economic indicators were a positive NPV of USD 48.846 with an IRR of 9.72% and a B/C ratio of 1.16. The risk analysis predicted a probability of an NPV 49.94% above the base case. The study of the social aspects suggested that the construc- tion of power plants has a positive impact in the form of increased community income and the growth of new economic sectors that utilize electricity as a primary source. An analysis of the envi- ronmental effects is critical so that the impacts can be minimized. Overall, the construction of small- scale power plants in oil palm plantations is worth considering as long as it is carried out following the applicable regulations.
Keywords: gasification; multi-stage; techno-economic; power plant; oil palm waste
1. Introduction
The availability of clean energy is necessary to meet national energy needs to effi- ciently support the goal of the sustainable development of new and renewable energy in Indonesia. By 2025, it is expected that the renewable energy mix can grow to 23% with an installed capacity of 5500 MWe as shown in Figure 1. Until 2018, the percentage of renew- able energy utilization reached 6.2%. The bioenergy sector is expected to contribute 8.2%
to national energy, one way of which is through the development of bioenergy power plants [1]. The utilization of new and renewable energy has become a topic of interest and is on the agenda in the world as one of the solutions to overcome the problems of the current energy crisis. The cause of this energy crisis is the decreasing availability of fossil fuels. Biomass, because of its abundant availability, can substitute for the use of fossil fuels. Compared to other renewable energy sources (wind, solar, etc.), energy production
Citation: Isgiyarta, J.; Sudarmanta, B.; Prakoso, J.A.; Jannah, E.N.; Saleh, A.R. Micro-Grid Oil Palm Plantation Waste Gasification Power Plant in Indonesia: Techno-Economic and Socio-Environmental Analysis.
sEnergies 2022, 15, x.
https://doi.org/10.3390/xxxxx Academic Editor(s):
Received: 7 December 2021 Accepted: 19 January 2022 Published: date
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from biomass requires lower capital investment costs [2]. To encourage the acceleration of the use of renewable energy in Indonesia, the government has established various pol- icies. The government has the target of an additional installed capacity from renewable energy power plants of 905.73 megawatts (MW), consisting of 196 MW from geothermal powerplants, 557.93 MW from hydro power plants, 138.8 MW from solar power plants, and 13 MW from bio power plants. Meanwhile, the renewable energy investment target in 2021 will increase to USD 2.05 billion or approximately IDR 28.9 trillion (assuming an exchange rate of IDR 14,100 per dollar) from the investment achievement in 2020, which amounted to USD 1.36 billion or approximately IDR 19.2 trillion. Some of the govern- ment’s policies on new energy are as follows [3]:
a. Implementation of the mandatory B30 program for all sectors, followed by the devel- opment of biodiesel trials as a substitute for fossil diesel with B100 (biodiesel 100%) development technology;
b. Mixing of research octane number 92 Oil Fuel in East Java in the context of efforts to procure bioethanol-type biofuel, in accordance with the Regulation of the Minister of Energy and Mineral Resources Number 12 of 2015;
c. Acceleration of waste power plant development in 12 selected cities, as mandated by Presidential Regulation Number 35 of 2018 concerning the acceleration of waste power plant development programs;
d. Encouraging the use of rooftop solar power plants in accordance with the mandate of the Minister of Energy and Mineral Resources Regulation Number 49 of 2018 con- cerning the Use of Rooftop Solar Power Generation Systems by state power plant consumers;
e. Simplifying the bureaucratic process through the of Energy and Mineral Resources Online Licensing Application, which is integrated with data on natural resources, operations, production, and marketing/sales of each type of energy;
f. Increasing the use of renewable energy to reduce dependence on fossil fuels, which will have an impact on increasing Indonesia’s economic stability.
Figure 1. Primary energy supply by 2025.
The utilization of biomass waste into energy can be a solution to reduce dependency on fossil fuel. The potential energy from biomass is currently at 32,654 MW and 1716.5 MW has been developed [4]. Development of bioenergy-based power plants (on-grid) un- til 2013 reached 90.5 MW, while for those off-grid it reached 1626 MW [5]. One of the most significant biomass potentials in Indonesia is from solid waste from oil palm plantations.
Oil palm plantations in Indonesia are the largest source of biomass with a total electricity energy that can be generated of 5495 MWe [6]. The sources come from plantation wastes (oil palm fronds and oil palm trunks) or waste from oil palm mill production (meso scrap
28%
23%
28%
21%
Renewable Energy Oil Coal Gas
fiber, palm kernel shell, and oil palm mill effluent). However, not all these wastes are utilized as energy, so they have the potential to become sources of greenhouse gas emis- sions when they decompose. In addition, in terms of the environment in recent years, the oil palm plantation industry in Indonesia has been in the European Union’s and the United States’ spotlight because it is considered an industry that is not environmentally friendly due to the impact it causes [7]. If the renewable energy target policy is imple- mented by 2030, it is expected to reduce greenhouse gas emissions by 29% compared to 2010.
Indonesia has five provinces with the most extensive oil palm plantations, namely, South Sumatra, Central Kalimantan, West Kalimantan, North Sumatra, and Riau. In 2019, the Indonesian State Electricity Company reported that Indonesia’s electrification ratio had reached 99%. However, the electrification ratio is still calculated from the number of people who obtain electricity for access to lighting and not for the productive sector. The Ministry of Energy reported the data on villages that did not have access to electricity to be as many as 2281 villages out of a total of 232,128 villages in Indonesia [1]. Meanwhile, for the five provinces with the most extensive oil palm plantations, there are 785 villages, 2510 villages, 13,595 villages, 634 villages, and 5209 villages, respectively, as shown in Figure 2. The condition is ironic, since these five provinces produce much of the oil palm plantation waste. At present, access to electricity only benefits people in urban areas where there is an installed electricity network. In contrast, construction of the network constrains those plantations because the cable must pass through the plantations. Thus, the issue of land acquisition is a significant factor in the lack of access to electricity in rural communities located in oil palm plantations.
Figure 2. Villages that have no access to electricity in Indonesia.
Oil palm plantation wastes are oil palm fronds and oil palm trunks. Oil palm fronds during pruning and replantation activities are always stacked and collected at an average production rate of 9.8 t-dry/ha-estate/year and 14.9 t-dry/ha-replantation/year. A study reported that oil palm fronds contain 25.5% (dry basis) hemicellulose material, which has excellent potential to be used as a raw material for biofuels and bio-based material pro- duction [8–11]. Oil palm trunks are the second type of biomass residue produced during replanting. Oil palm trunk production is estimated at 62.8 t-dry/ha-replantation/year. At present, oil palm fronds are usually burned as fuel in processing plants, and the remainder is disposed of in plantations, while oil palm trunks after the replanting process are not utilized [10]. Utilization of oil palm waste as a raw material for renewable energy that can generate electricity is a solution to the residue of oil palm industry activities in Indonesia.
According to the Ministry of Energy and Mineral Resources of the Republic of Indonesia,
the renewable energy market in Indonesia is not yet optimal because it relies on solar panels which have components that are imported. Thus, the government is pushing a draft Indonesian Presidential Regulation that will regulate the price of new renewable electricity. Through this policy, it is hoped that the production of renewable energy that utilizes oil palm waste as a raw material can grow in oil palm industrial areas in Indonesia.
In addition, the push for the use of renewable energy is in line with the global commitment to the 7th point of the Sustainable Development Goals that are to be achieved by 2030 regarding clean and affordable energy.
One technology that can be used to convert biomass into alternative energy without producing emissions is gasification [12]. Gasification is the process of converting solid or liquid raw materials into thermochemical gases [13]. Different to combustion, gasification produces higher efficiency, and the pollutants are still below emissions standards. The gasification process consists of several sequential stages, namely, the drying, pyrolysis, partial oxidation, and reduction stages. Gasification requires media such as air, oxygen, or water vapor. The gas produced from the gasification process, commonly called syn- thetic gas (syngas), consists of combustible syngas (i.e., CO, H2, and CH4) and non-com- bustible gas (i.e., CO2, N2, and the remaining O2) [14]. Gasification reactions occur in a reactor called a gasifier. There are various types of gasifiers such as updraft, downdraft, cross draft, bubbling fluidized bed gasifiers, and circulating fluidized beds (CFBs) [15].
One type of gasifier that is widely used is the downdraft [16–18]. A downdraft gasifier has the advantage of a high carbon conversion rate, low tar production, and simple construc- tion compared to other types [19].
The aim of this study was to analyze the utilization of oil palm plantation waste as fuel in gasification power plants. The analyses simultaneously carried out were technical, economic, investment risk, social, and environmental impact analyses. Oil palm planta- tion wastes used were oil palm fronds and oil palm trunks. Both of these plantation wastes have been reported by several previous studies and are suitable as feedstock for gasifica- tion. The power plant analyzed was upscaled from a laboratory-scale prototype with a capacity of 10 kW, which has been reported in previous studies, to a small-scale power plant with a capacity of 100 kW. The gasification technology used the multi-stage downdraft gasifier [20]. This technology has the advantage of being able to produce syn- gas with a high–low heating value and a low tar content of 2.6 times compared to the single-stage downdraft gasifier that has been reported in other studies. Moreover, this multi-stage gasification technology was also equipped with an air heating system that was also capable of producing low tar content up to 27.8 mg/Nm3 and temperature increases at the partial oxidation zone with a constant equivalent ratio [18].
Several previous studies using gasification technology for power generation have been carried out. Romaniuk [21]conducted research by utilizing agricultural waste as fuel in gas generators. Modification of the gas generator was conducted by adjusting the sup- ply of oxidizer (air supply) into the reaction zone. A downdraft-type gasification power plant with a capacity of 25 kW was also developed by ENTRAGE Energies System AG, using a 4.3 L six-cylinder petrol engine coupled to an electric generator. A downdraft-type gasification power plant was also developed by ALL POWER LABS with a power output of 15 kW [21,22]. The gasifier was coupled to a four-cylinder diesel engine and an electric generator. Currently, one of the largest biomass power plants is located in the UK, near Cheshire, and it produces 21.5 MW of electrical energy. A gasification power plant with a capacity of 100 kW in current market conditions is more profitable than a larger capacity provided that the fuel used is not difficult to supply [23]. Situmorang [24] reports that gasification power plants can be used to utilize locally available biomass as fuel with a generating capacity of less than 200 kW.
Before the power plant was implemented, it was necessary to evaluate the feasibility and sustainability of the project in terms of economic, social, and environmental as well as the risk variables that could hinder the success of the project. Some analyses that needed to be conducted were techno-economic, risk, and social–environmental. Techno-economic
analyses of gasification power plants have been carried out in several previous studies.
Porcu [25] conducted a techno-economic analysis of a gasification power plant being up- scaled from 500 to 200 kW using a bubbling fluidized bed gasifier. Singh conducted a techno-economic analysis of hybrid power plants between gasification, solar PV, and fuel cells, but the gasification technology used was not mentioned. Economic and environmen- tal impact analyses of an 11 MW capacity gasification power plant were carried out by Cardoso [23], and the results of the study reported that the NPV was influenced by reve- nue from electric sales. Sobamowo [26]conducted a techno-economic analysis of a gasifi- cation power plant using downdraft gasification technology with a capacity of 60 MW;
the results of the study reported that the distance between the power plant and the source of raw materials affected the raw material costs. Moreover, local materials for capital in- vestment, maintenance, and fuel costs provided higher profit margins.
Emiliano [27,28] conducted a techno-economic assessment of power plants with gas- ification technology. The results of the study reported that the price of gaseous fuel (i.e., natural gas) dramatically affects the economics of the power plant project. In addition, power efficiency and the selling price of electricity can produce a higher NPV. Cali [29]
conducted a techno-economic analysis of the FOAK industrial gasification plant. The re- sults of the study reported that the cost of fuel dramatically affects the cost of electricity (COE), and the economic results can be increased by technical development to reduce op- erating costs. Kivumbi [30] conducted a techno-economic analysis of a gasification power plant with a capacity of 425 kW using municipal solid waste as fuel. The results of the study reported that for small-scale power plants, a high interest rate causes the return on investment to be longer, so it is not appropriate. In addition, the distance between the source of raw materials and power plants affects the total cost of transportation to increase the cost of electricity production. Gokalp [31] conducted a techno-economic analysis of a gas tire scrap power plant capacity of 5 MWe. The gasification technology used was a circulating fluidized bed. The results of the study reported that the price of raw materials dramatically influences the financial result, but if it cannot be reduced, the efficiency of the gasification system needs to be increased. Based on the results of the published techno- economic analyses, various variables affect the financial results of a gasification power plant and are different for each region, the type of raw material used, and the planned generating capacity. Moreover, most publications only discuss the economic analysis, and only a few discuss investment, social, and environmental risk analyses simultaneously, while these are interrelated. The generating capacity analyzed was also medium- to large- scale, while for the microscale, the literature is still limited.
This research is critical because of the limitations in the literature on technical and economic analyses; specifically, it was a small-scale 100 kW gasification power plant that utilized oil palm plantation waste as the primary fuel. In this study, the technical analysis carried out to calculate the capacity of the gasification system was based on the type of solid fuel and internal combustion engine. Meanwhile, the economic analysis conducted was calculated as the net present value (NPV), internal rate of return (IRR), benefit-to-cost ratio (B/C), and payback period (PBP). The investment risk was also analyzed using the Monte Carlo method. Furthermore, the final analysis carried out was an analysis of the social and environmental impacts due to the gasification power plant.
2. Materials and Methods
Multi-stage gasification power plant experiments have been carried out previously at the pilot scale with a capacity of 10 kW [18,20,32]. To estimate the economic value of a power plant on a micro-grid scale, in the analysis, the capacity was upscaled to 100 kW.
The aim was to obtain the difference between the non-profit models on the prototype scale and a profitable model on a commercial scale. The results of the pilot-scale experiment were used as a reference for modeling the performance of microscale gasification power plants. The technical aspects discussed in this study are feedstock characterizations using ultimate and proximate analyses, explanations of experimental activities, and analysis of
economic models. Techno-economic analyses were carried out including investment costs and operating costs. Meanwhile, for the technical analysis, the size of the biomass power plant was upscaled. Furthermore, an income analysis was carried out based on financial assumptions. After the technical aspects were defined, the next step was to perform an economic analysis and socio-environmental analysis. The Monte Carlo method was used for the risk analysis with Crystal Ball software Version 11.1.2.4®.
2.1. Multi-Stage Downdraft Gasification Power Plant
The experiments of pilot-scale gasification were conducted using a single-throat downdraft gasifier that was modified from a single-stage to a multi-stage [18]. The ad- vantage of this multi-stage gasifier is that it produces syngas with a lower tar content and a higher heating value. The multi-stage gasification technology was developed in the com- bustion laboratory and an energy system from the Sepuluh Nopember Institute of Tech- nology. The scheme of the gasification system is shown in Figure 3.
Figure 3. Prototype of a multi-stage downdraft gasifier.
The solid fuel consumption of this reactor was 8 kg/h. Before entering the reactor, the fuel was placed inside a hopper equipped with a screw conveyor. The amount of fuel entering was regulated through the screw rotation of the screw conveyor. The air used was ambient air, and before entering the gasifier, it was preheated until 200 °C. In addition to obtaining external heating, the air was also internally heated inside the gasifier by plac- ing an air ring in the form of a pipe that circled the inner wall of the reactor. In the first stage, the air was injected into the pyrolysis zone using six nozzles. The air in this pyrol- ysis zone initiated the oxidation reaction between the air and carbon, called oxidative py- rolysis [20,33–36]. The oxidation reaction released heat so that the pyrolysis properties changed from endothermal to exothermal. This was advantageous because the released heat from the partial oxidation zone was reduced. The temperature increased in the py- rolysis zone cracking the tar components from primary to secondary tar [18].
Furthermore, at the second stage, the air was injected in the partial oxidation, pre- cisely above the throat. In this position, the air was not distributed using the air ring be- cause it was heated from the oxidation region. Finally, in the third stage, the air entered the reduction zone using an air ring divided by six nozzles. Air entering the reduction