TEcHNO-EcONOMIc cOMPARATIVE STUDY OF

Teknologi Indonesia © LIPI Press 2014

Teknologi Indonesia 37 (2) 2014: 90–99

TECHNO-ECONOMIC COMPARATIVE STUDY OF VERY LOW HEAD HYDRO POWER: CASE STUDY IN BINTAR VILLAGE, NUNUKAN, EAST KALIMANTAN Ridwan Arief Subekti and Pudji Irasari

Research Centre for Electrical Power and Mechatronics– Indonesian Institute of Sciences Kompleks LIPI, Jalan Sangkuriang, Gedung 20 Lantai 2 Bandung 40135 Phone (022) 2503055 E-mail: [email protected] Received: 20-01-2014

Accepted: 01-04-2014

ABSTRACT This paper discusses techno-economic comparative study of very low head hydro power (VLHHP) between the penstock and non-penstock systems. The selected location is river current in the Bintar Village, Nunukan, East Kalimantan. The technical analysis is performed to determine the generated potential power, the type of components used and the investment cost per kW needed. The economic analysis is then conducted by implementing IRR and NPV methods to find out whether the project is economically feasible to be executed. The technical analysis results exhibit that the generated power using penstock system is higher than that of using non-penstock system; that is, 5.70 kW. The power of non-penstock system of 3.336 kW could be attained by applying modular system comprised by 4 units of propeller turbines installed in parallel. The economic analysis shows that the penstock system requires higher investment cost that is Rp58,480,272 and both systems are not feasible to be realized since they have negative NPVs. It is, therefore, recommended to fund the project through grant. Keywords: river current, very low head, penstock system, non-penstock system, techno-economic analysis ABSTRAK Makalah ini membahas perbandingan kajian tekno-ekonomi pembangkit listrik tenaga air dengan head sangat rendah antara sistem penstok dan non-penstok. Lokasi yang dipilih adalah arus sungai di Desa Bintar, Kabupaten Nunukan, Kalimantan Timur. Kajian teknis dilakukan untuk mengetahui potensi daya yang dibangkitkan, jenis komponen yang digunakan, serta biaya investasi per kW. Analisis ekonomi yang menggunakan metoda IRR dan NPV selanjutnya dilakukan untuk mengetahui apakah proyek yang akan dikerjakan layak untuk direalisasikan. Hasil analisis teknologi menunjukkan bahwa daya yang dibangkitkan oleh sistem penstok lebih tinggi dibanding sistem non-penstok, yaitu 5,70 kW. Daya sistem non-penstok sebesar 3,336 kW dapat dicapai dengan menerapkan sistem modular, yaitu dengan menggunakan 4 unit turbin propeler yang dipasang secara paralel. Hasil analisis ekonomi memperlihatkan bahwa sistem penstok memerlukan biaya investasi lebih tinggi yaitu Rp58.480.272 dan kedua proyek tidak layak untuk dikerjakan karena NPV-nya bernilai negatif. Oleh sebab itu direkomendasikan agar proyek didanai melalui dana hibah. Kata kunci: arus sungai, head sangat rendah, sistem penstok, sistem non-penstok, analisis tekno-ekonomi

INTRODUCTION Indonesia has many large rivers, some which are: Kapuas, Barito, and Mahakam Kalimantan, Bengawan Solo and Citarum Java, Musi and Asahan in Sumatra as well

90

of in in as

Memberamo and Digul in Papua. According to the Government Regulation,[1] rivers can be utilized for households, agriculture, sanitation, industries, tourisms, sports, fishing, defense, power generations and transportations. Various

Ridwan A.S. and Pudji I |Techno-Economic Comparative ...

efforts have been made by the government to explore these functions properly. However, for power generations particularly, until now, mostly were built by utilizing the waterfall and not the river current, which may imply the use of no dam, reservoir or augmentation. Problems of design, operation, and economic are obstacles and challenges altogether to explore it as an energy source.[2] Nevertheless, with the development of the technology of low-speed permanent magnet generators (PMG), those problems could be solved. By applying low-speed PMG in hydro power plant, the mechanical transmission ratio could be reduced or even abolished (called “direct drive system”), which leads to a better system efficiency. Conversion of the river current into electrical power requires a technology usually called LHHP. The turbine type for low head application is generally of reaction turbines, which are kaplan and propeller. Yet for the case of small river with low potential of power, Kaplan turbine is less suitable because it is expensive and has complicated construction. Propeller turbine is more frequently used to operate on the head of between 3-20 m.[3] Several studies on the design and optimization of low head hydro turbines are discussed in [4,5,6] while the implementations with the head of less than 1 m are conducted by [7,8,9] , usually called very low head hydro power (VLHHP). Some rivers in Indonesia mentioned above have the characteristics of large debit but very low head. VLHHP technology is suitable for such circumstances. This paper discusses the comparative techno-economic study of two types of power plants. Those are penstock and non-penstock systems of VLHPP, that could be employed in one of the rivers in Bintar Village, East Kalimantan.

to find out the generated power. A point along the river is then determined as the plant location considering the proximity to the settlements. Referring to those parameters (the generated power and the plant location), the components and the construction type of each plant are specified. Afterward, the economic analysis is performed to obtain the price of electricity per kWh and to find out the feasibility of the project.

Small Hydro Power Technology Small hydro power (SHP) is usually based on a dam, penstock and canal. The plant is constructed by utilizing different altitude and conveys water to the turbine through the penstock. The kinetic and potential energy of water are converted into energy of motion such as turbine rotation that is then converted into electrical energy by a generator. In constructing a hydroelectric plant, the head is not always derived from a natural waterfall. It could be acquired by making intake on the river, running the water into the right place and storage it in a basin, forming an ideal height. For Propeller turbine, head is calculated from the up to the bottom of water level.[10] Layout of SHP applying propeller turbine is shown in Figure 1. This model requires various civil constructions such as intake, weir, pipe or canal, forebay tank, turbine housing and tail race. Water in the weir is tapped through the intake then flows through canal into forebay tank. Furthermore, the water flows into the penstock, and then enters the turbine located on the turbine house and flows out through the tail race. Once the turbine rotates, the generator connected to

DESIGN AND METHODOLOGY Utilization of the river in Bintar Village, East Kalimantan, for power plant is assessed through comparative techno-economic study of two types of VLHHP, which are pestock and non-penstock systems. The obtained data including head, flow rate, width and depth of the river are formulated

Figure 1. Layout of SHP applying propeller turbine.[10]

91

Teknologi Indonesia 37 (2) 2014

the turbine shaft also rotates to produce electric power.

Very Low Head Hydro Power VLHHP in this paper is defined by the head of less than 3 m. The system may be with or without penstock depending on the location where it is going to be installed. The energy conversion requires the use of very low head turbine (VLHT) that gives several advantages such as low cost of system installation, simple civil construction, reliable, easy to operate, and fish population friendly.[7] The implementations of VLHT on a river are depicted in Figure 2 and 3.

into electricity using water turbine and generator. HPP is classified according to its capacity as shown in Table 1.

[12]

The acquired data comprise flow rate v [m/s], cross-sectional area of the river A [m2] and the effective head Heff [m]. They are then applied to the following equations,

(1)

(2)

where Q = debit [m3/s], P = generated power [W], ρ = water density = 1000 kg/m3, g = gravity = 9.81 m/s2, and η = efficiency of the system.[13]

Power Estimation

Economical Analysis

Hydroelectric power plant (HPP) converts the power of water, with a certain head and debit,

Investment costs calculation Planning a MHP project cannot be separated from the budget planning. Cost calculations applied in this paper refers to the empirical equations developed by Singal,[3] that estimate the costs involved in the construction of mini-scale hydro power plant. This approach is taken because the investment cost per kW calculated by Singal,[3] which is in the range of US$ 809–1,774, is close to the calculation results performed by several studies that have been conducted in Indonesia, as represented in Table 2.

Figure 2. VLHHP using single VLHT.[7]

Figure 3. VLHHP using a parallel of VLHT.[11] Table 1. Classification of HPP. Description Large Medium Small Mini Micro

92

Magnitude of total capacity > 50 MW 20 – 50 MW 5 – 20 MW 1 – 5 MW < 100 kW

In the formulas, the Indian Rupees currency (Rs) is converted in Rupiah (IDR) before being inserted in the equations. The exchange rate used is 1 US $ = Rs 54.99 and 1 US$ = Rp9.638.[19] In addition, the incentive factor of 1.3 is also included in the calculation, which are applied to Kalimantan, West and East Nusa Tenggara.

Table 2. The estimation of investment cost of miniscale hydro power plant by some studies in Indonesia. Study performed by R. Kristiyani, 2010[14] Pusat Studi Energi UGM, 2010[15] S. Gitosusastro, 2010[16] PT Bajradika Rangkiang Energi, 2010[17] Bumiloka Cikaso Energi, 2009[18]

Investment cost per kW (US$) 950–4,500 1,298–1,354 1,472


The cost per kilowatt in rupiah is calculated using the following equations:

[20]

Diversion weir and intake, C1 = 12.415 P -0,2368 H -0,0597

(3)

Power canal, C2 = 85.383 P -0,3811 H +0,0307

(4)

Forebay and spillway, C3 = 25.402 P -0,2356 H -0,0589

(5)

Penstock and foundation, C4 = 7.875 P -0,3806 H +0,3804

(6)

Power house, C5= 92.615 P -0,2351 H -0,0585

(7)

Tail race, C6 = 28.164 P -0,376H -0,624

(8)

Turbine and governor, C7 = 63.346 P -0,1913 H -0,2127

(9)

Generator and excitation system, C8 = 78.661 P -0,1855 H -0,2083

(10)

Electrical and mechanical equipment, C9 = 40.860 P -0,1892 H -0,2118

discounted cash flow method, which is a popular capital budgeting technique that takes into account the time value of money. NPV is the difference between the present value of cash inflows and the present value of cash outflows that occur as a result of undertaking an investment project. It may be positive, zero or negative. Positive NPV, if present value (PV) of cash inflow > PV of cash outflow, so that the project is acceptable. Zero NPV, if PV of cash inflow = PV of cash outflow, so that the project is acceptable. Negative NPV, if PV of cash inflow < PV of cash outflow, so that the project is not acceptable. NPV can be calculated by the equation,

(12)

where At = the net cash flow at time t, k = the discount rate, t = the time of the cash flow, n = the total number of periods. Internal Rate of Return (IRR) is basically a method to calculate the interest rate that can equate the present value of all cash inflows with cash flows from an investment project. This method in principle is used to calculate the actual rate of return. IRR should be sought by trial and error. With r is interest rate, IRR is represented by:[21]

(11)

(13)

Cost Benefit Analysis There are several cost components involved in the construction of MHP, which can be broken down as follows: 1) Development Cost, including: cost of hydro potential study, pre-feasibility study, feasibility study/detail design, license, and land acquisition; 2) EPC Cost or engineering, procurement and construction costs; 3) Financing Cost, including: IDC and financing fee; 4) Initial Working Capital. Cost benefit analysis methods used in this paper are the Net Present Value (NPV) and Internal Rate of Return (IRR). NPV also known as

RESULTs AND DISCUSSION Measurement Results The surveyed river is located in the Bintar Village, Lumbis Sub-district, Nunukan District, East Kalimantan Province. It has the stream character as shown in Figure 4. This river is not far from the settlement and very suitable for MHP location because it will facilitate the transport of material during the construction, reduce transmission and distribution costs, as well as make surveillance, maintenance and operation become easier. Some parameters including width and depth of the river, flow rate and the effective head have been

93


Figure 4. The surveyed river. Table 3. Measurement result of the parameters. Simbol

H

Parameters

Magnitude

Unit

Average river width

4

m

Average river depth

0.33

m

Average flow rate

0.38

m/s

Effective head

1m High Expensive Many Expensive Complex High Cheap Expensive High Standard

Non-penstock system Close to settlement 1m Low Cheap Few Cheap Simple High Expensive Cheap High Easy

97


The cost benefit analysis results show that the IRR of both the MHP systems are smaller than the current interest rate of 10% and their NPV values are negative. When considering only the economic terms, the construction of MHP is actually not commercially feasible, especially when it is financed through grant.

ACKNOWLEDGMENT

Furthermore, the advantages and disadvantages between the two systems are compared as presented in Table 10.

[1] Anonim. (2011). Peraturan Pemerintah Republik Indonesia Tentang Sungai. No. 38. [2] Khan, M.J., M.T. Iqbal and J.E. Quaicoe. (2008). River current energy conversion systems: progress, prospects and challenges. Renewable and Sustainable Energy Reviews, (12): 2177–2193. [3] Singal, S.K., R.P Saini and C.S Raghuvanshi. (2010). Analysis for cost estimation of low head run-of-river small hydropower schemes. Energy for Sustainable development, (14): 117–126. [4] Stark, B.H., E. Ando and G.G. Hartley. (2011). Modelling and performance of a small siphonic hydropower system. Renewable Energy, (36): 2451–2464. [5] Date, A., A. Akbarzadeh and F. Alam. (2012). Examining the potential of split reaction water turbine for ultra-low head hydro resources. Procedia Engineering, (49): 197–204. [6] Shimokawa K., A. Furukawa., K. Okuma., D. Matsushita and S. Watanabe. (2012). Experimental study on simpliﬁcation of darrieus-type hydro turbine with inlet nozzle for extra-low head hydropower utilization. Renewable Energy, (41): 376–382. [7] MJ2. (2008). Hydro turbine generating set for very low head-a new turbine for very low head applications and low environmental impact. [Online]. http://2010.hidroenergia.eu/pdf/3B.07. pdf. [8] Power, 3Helix. (2011). Types of turbines. [Online]. http://www.3helixpower.com/hydropower/ types-of-turbines/. [9] Subekti, R.A., A. Susatyo and P. Irasari. (2012). Design and analysis of the prototype of pico hydro scale submersible type turbine-generator for flat flow river application. Jurnal Teknologi Indonesia, 35 (3): 1–8. [10] Teknik, Cihanjuan Inti. (2009). Turbin propeller open flume. [Online]. http://www.hanjuang.co.id/ produkCF1.html. [11] Bihlmayer, A. (2005). Innovative Solution for Low Impact Hydropower at Existing Engineered Structures. [12] Arismunandar, A. and S. Kuwahara. (1991). Buku Pegangan Teknik Tenaga Listrik: Pembangkitan dengan Tenaga Air. Jilid I. Edisi Keenam. Jakarta: PT Pradnya Paramita.

Selecting one of the two technologies compared above is not only taking into account the investment cost but also another important factor; that is, the certitude of the sustainably operation of the system. In this case, both systems studied are not economically feasible (negative NPV) and the project should therefore be funded through grant. With a good management system, the plant can be guaranteed to operate continuously. Furthermore, this kind of project may be registered as a Clean Development Mechanism (CDM) project to improve IRR. According to study conducted by Febijanto,[23] by implementing CDM, IRR can be increased around 27%.

CONCLUSION Techno-economic comparative study of VLHHP technology between penstock and non-penstock systems taking location in Bintar Village, East Kalimantan, has been discussed in this paper. From technology point of view, both systems have advantages and disadvantages, respectively. However, the penstock system produces higher power (5.70 kW) and needs higher investment costs per kW; that is, Rp58,480,272. Meanwhile, the cost benefit analysis results indicate that both system are not commercially feasible since the NPV values are negative; those are Rp79,391,310 for penstock system and Rp19,556,750 for nonpenstock system. From economic point of view, both systems are recommended to be funded through grant and to establish good organization for sustainably operation.

98

The authors would like to thank to the Local Go vernment of Nunukan District, East Kalimantan, for any assistance that have been given.

REFERENCES


[13] Dietzel, F. (1990). Turbin Pompa dan Kompresor. Edisi Kedua. Jakarta: Erlangga. [14] Kristiyani, R. (2010). Overview PLTMH–peluang dan tantangan. Materi Pelatihan Analisisa Kelayakan Proyek Pembangkit Tenaga Listrik Mini Hydro Tahun 2010. Jakarta. [15] UGM, Pusat Studi Energi. (2009). Kajian ulang kelayakan PLTM Bonar Provinsi Nusa Tenggara Timur. Materi Pelatihan Analisis Kelayakan Proyek Pembangkit Tenaga Listrik Mini Hydro Tahun 2010. Jakarta. [16] Gitosusastro, S. (2010). Analisis ekonomi dan finansial. Materi Pelatihan Analisis Kelayakan Proyek Pembangkit Tenaga Listrik Mini Hydro Tahun 2010. Jakarta. [17] Energi, Bajradika Rangkiang. (2010). Studi kelayakan PLTM Lubuk Sao II. Materi Pelatihan Analisis Kelayakan Proyek Pembangkit Tenaga Listrik Mini Hydro Tahun 2010. Jakarta. [18] Energi., Bumiloka Cikaso. (2009). Laporan Studi Kelayakan Pembangunan PLTM Cikaso Sukabumi Jawa Barat. Jakarta.

[19] id.rateq. (2013). Kurs Asing. [Online]. http:// id.rateq.com/INR. [20] Anonim. (2009). Peraturan Menteri ESDM No. 31 Tahun 2009 tentang Harga Pembelian Tenaga Listrik oleh PLN (Persero) dari Pembangkit Tenaga Listrik yang Menggunakan Energi Terbarukan Skala Kecil dan Menengah atau Kelebihan Tenaga Listrik. [Online]. http://prokum.esdm.go.id/permen/2009/Permen%20ESDM%2031%202009. pdf. [21] Suliyanto. (2010). Studi Kelayakan Bisnis: Pendekatan Praktis. Edisi ke1. Yogyakarta: ANDI. [22] Harvey, A., A. Brown, P. Hettiarachi, A. Inversin. (2002). Micro-Hydro Design Manual, a Guide to Small-Scale Water Power Schemes. London: ITDG Publishing. [23] Febijanto, I. (2013). Economic analysis of Cikaso Mini Hydro Power Plant as a CDM Project for increasing IRR. Mechatronics, Electrical Power, and Vehicular Technology, 4 (2): 89–98. DOI:10.14203/j.mev.2013.v4.89–98.

99