FEASIBILITY ANALYSIS ON THE INSTALLATION OF A WIND TURBINE IN SMALL ISLAND OF THAILAND

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1 FEASIBILITY ANALYSIS ON THE INSTALLATION OF A WIND TURBINE IN SMALL ISLAND OF THAILAND Mr.Watthana Limpananwadi System Development Division Provincial Electricity Authority 2 Ngam Wong Wan Rd., Chatuchak, Bangkok, Thailand, 19 Tel wlimpanan@pea.co.th Mr.Warich Khun-Aksorn System Development Division Provincial Electricity Authority 2 Ngam Wong Wan Rd., Chatuchak, Bangkok, Thailand, 19 Tel boypotter@yahoo.com Assoc. Prof. Dr. Worawit Tayati Department of Electrical Engineering Chiang Mai University, Chiang Mai, Thailand 52 worawit@eng.cmu.ac.th Abstract In Thailand, there are a number of small mountainous areas and islands far away from the distribution network, which are under the responsibility of the Provincial Electricity Authority (PEA). To meet the Royal Thai Government policy to supply electricity to these regions, the electricity generation using diesel generator is employed. At the moment, due to higher oil price and lower price of energy sale as compared to the energy production cost, PEA faces a huge loss on such electricity generation about hundreds million Baht per year. Therefore, to decrease such loss, the electricity generation using renewable energy is introduced in the site with potential resource. The paper presents a feasibility analysis on the installation of a wind turbine in a small island. A case study at Ko Tao supplied with a set of diesel generators is investigated. Site survey had been conducted and processed to select the suitable site for the wind turbine installation. Furthermore, the wind data obtained from the wind monitoring at the special site about one year were analyzed to ensure that the wind performance is reasonable. Moreover, the technical, financial and economic analysis was carried out and discussed in detail. Keywords: Wind Turbine, Renewable Energy, Diesel Generator, Distribution Network. 1. Introduction At the end of 22, there was a total wind turbine capacity of 31, MW installed to generate electricity power worldwide [1]. It was predicted that it would be 1,2 GW in 22. The development of wind energy technology is focused on rated power, rotor diameter, hub height, potential annual and energy yield. The rated power of wind turbine was upgraded from 3 kw to 5 MW in 198 and 25 respectively with bigger rotor diameter and higher hub height. There are many researches concerning technical and environmental issues of small wind turbine application. To improve a weak system, the wind turbines using synchronous generators are proposed with both woundfield and permanent magnet rotors, which they can control the output power factor [2]. However, the impacts of wind turbine on distribution system must be considered. The impact of induction wind turbine on voltage stability is mentioned in [3]. It shows that the voltage stability is affected by the capacity of wind turbine when connected to a weak network. Moreover, the power injected from a small wind turbine into a DC bus is presented in [4]. The concept is used for installing small windmills on their own properties to offset the load. Besides, the environmental issues of wind turbine are important when it located close to community [5]. In Thailand, the wind energy is applied typically for water pumping purposes in remote areas. In 1983, the wind energy application for electricity generation was experimented by the Electricity Generation Authority of Thailand (EGAT) in Phuket Province. Four small wind turbines: 18.5, 2, 1 and.83 kws respectively were installed in a pilot station at Prom Thep Cape [6]. The result achieved indicated that the wind energy generation worked reasonably well but there were some problems on procuring spare parts from abroad in certain cases and on broken parts of wind turbine such as wheel blade and ball bearings. After that, in the early 199s, the wind turbines were applied to connect to the grid system. For the PEA responsibility areas, a wind turbine is being applied to the remote areas. Basically, they are supplied by a set of diesel generators. Due to sudden increase in oil price and cheap energy sale price, it has made a huge loss on the energy sale. This paper presents a feasibility analysis on the installation of a small wind turbine in small island of Thailand. Due to high fuel oil price and fixed energy sale price controlled by the government, PEA is now operating at a loss. Therefore, a small wind turbine is applied to a remote island supplied by a set of diesel generators to decrease the loss and fuel oil consumption. The paper starts with the electricity generation for the remote area in Thailand. Then, the system descriptions of case study and wind performance monitoring are discussed. After that, the financial and economic of a small wind turbine installation is analyzed in detail. 2. Electricity Generation for Remote Area PEA is a government enterprise under the Ministry of Interior. The PEA's major task is to supply electricity to all regions in Thailand, accounting for 99 percents of the country with the exception of Bangkok, Nonthaburi and Samut Prakran Provinces, and serve a basic infrastructure of the country according to the government policy with the emphasis on the efficiency, stability and safety power [7]. To meet the above policy, the diesel generator is applied to the remote areas with difficulty in grid connection. Presently, PEA has a total of 12 remote small areas including island and mountainous area [8]. The energy

2 production during Jan to Sep 25 is nearly 13.3 million kwh. In accordance with the government policy, the energy sale price for all residential customers is currently fixed at roughly 3. Baht/kWh. However, the energy production cost of PEA s diesel generator is 1.5 Baht/kWh, derived from the PEA s average diesel generator consumption at.286 liter per kwh and diesel oil price including transportation at 3 Baht/liter. From the energy production mentioned earlier, it is about 1 million Baht worth of PEA s loss. As a result, it makes a loss of worth several hundreds of million Bath per year. Therefore, the hybrid system: diesel generator and electricity generation using renewable energy is taken into account. Ko Nangyuan 3 KVA 1 KVA 12 PIC 3. Research Methodologies The purpose of this study is to investigate the feasibility of the wind turbine installation in the small island to reduce the loss. Details of activities carried out in each stage are given below. Site survey; a field trip to the area had been conducted to obtain the site for wind monitoring and installation. Face to face interviews with local village headmen, Sub-District Administration Organization and villagers were performed to collect the key data on site selection. Wind performance monitoring; after obtaining the site, the wind data was recorded to investigate the wind performance by using data loggers. Wind performance analysis; the wind data was analyzed to evaluate the potential of the wind energy production. Technical, financial and economic analysis; the existing system performance was monitored and analyzed. Then, the analysis of financial and economic is assessed. 4. Case Study 4.1 System Descriptions Ko Tao is a small tropical island with incredible snorkeling and scuba diving, a rich jungle in the centre and surrounded by remarkably quiet, palm tree laced beaches. It is located about 75 km southeast of Chumphon Province with a famous tourist attraction and environmental issues. The 33 kv system is supplied by a set of 6 small diesel generators with a total capacity of approximately 3, kw operated by PEA. The system load is about 75 kw as of September 25. The demand growth is controlled by PEA with limit of meter size. The map and distribution system is shown in Fig.1. The island is fully mountainous area and tropical forest. There is no electrification in some areas since it is difficult to extent the grid and being of diesel generation limit. 4.2 Site Selection From the site survey, there are few sites suitable for wind turbine installation due to high land price. At the beginning, the sites were processed and selected using wind flow directions and available grid connection. At the sites the wind speed was also measured using a potable cup anemometer. Finally, the appropriate site was selected as given in Fig.1. It is located at the southern area of island and far away from distribution system nearly 1 km. 25 KVA 3 KVA Diesel Power Plant 5 PIC 5 PIC 3 KVA 5 PIC 5 KVA 5 PIC 3 KVA 5 PIC 5 PIC Wind Turbine Location 5 PIC 3 KVA 3 KVA 3 KVA Figure1 Map and Distribution System of Ko Tao 4.3 Wind Performance Monitoring In November 22, a wind assessment system was installed at the site to confirm that it is suitable for a wind turbine location. The system is consisted of a tilt-up tower with 4 meters in height, instrument, sensors and accessories. During Nov to Dec 22, the wind data was analyzed to ensure that the data achieved was accurate. Afterward, the wind data was recorded in 23. The wind performance data obtained are processed and analyzed using MicroSite program [9] as follows; Monthly Gust Speed, Monthly Average Wind Speed and Monthly Temperature The monthly gust speed, average wind speed and temperature observed are shown in Fig.2. The minimum and maximum gust wind speed is m/s in April and m/s in August respectively. Besides, it is found that the average of monthly wind speed is about 5.38 m/s. In addition, it is worth noting that the temperature in April is very high but the wind speed is very low. Annual Wind Speed To show the temporal distribution of wind speeds and the frequency of varying wind directions [9], a graph so-called wind rose is employed as demonstrated in Fig.3. From data obtained, the prevailing wind direction is NE and SW. Besides, it is evident that the wind speed and wind energy achieved at SW is more than at NE.

3 Wind Speed (m/s) Jan Feb Mar Apr May Jun Jul Aug Months Sep Oct Nov Dec Temperature ( C) Monthly Gust Speed Monthly Average Wind Speed Monthly Temperature Figure 2 Monthly Gust Speed, Average Wind Speed and Temperature Site Number: 5 Start Date: End Date: W NW.15 SW N Outer numbers are averaged TIs for that sector Inner circle = % Outer circle = 3% NE.2 SE S Figure 3Wind Rose for Annual Wind Direction Site Number: 5 Start Date: End Date: Diurnal Wind Speed Pattern E Percent of Total Time Percent of Total Wind Energy turbine and energy generation selected will be discussed in the next section Wind Speed Frequency Distribution (%) < >15 Wind Speed (m/s) Figure 5 Wind Speed Frequency Distribution (%) 4.4 Wind Size Selection The size consideration of wind turbine is dependent on the budget and wind performance data obtained. The project budget is supported from the government, which is available under the government s Energy Conservation Promotion Fund (ECON Fund) and PEA investment. To stimulate the wind energy market in Thailand, the large commercial size is preferred. Finally, one large unit of 1.2 MW wind turbine classified in [1], is selected to generate power for this site as the power curve provided by manufacturer shown in Fig.6. Besides, the wind turbine size is designed according to the system load. In theory, the wind power is proportional to the area of windmill being swept by the wind, the cube of the wind speed and air density, which varies with altitude [11] Cumulative Frequency Wind Speed in M/S Wind Speed (m/s) Hours Figure 4 Daily Wind Speed Pattern The average of daily wind speed in 23 is shown in Fig.4. It is important to note that the peak wind speed is occurred during hrs and hrs. Wind Speed Frequency Distribution (%) The most important wind data is the wind speed frequency distribution as given in Fig.5. It shows the frequency of wind speed occurred. At 6 m/s wind speed was happened with 16.3%. Besides, it is obvious that at cut-in speed, in general at 3 m/s, the wind energy can not be generated roughly 11%, see the cumulative frequency graph. From the wind performance mentioned, it is clear that the island can be supplied by a wind turbine. The size of wind Power Output (kw) Fig.6 Power Curve of Wind Turbine Applied From the power curve above, the wind performance is described as follows; Cut-in speed at 3m/s: is the lowest wind speed at which a wind turbine begins producing usable power. Rated power at 1,2 kw: is the maximum power output of wind turbine. Cut out speed at 25 m/s: is the highest wind speed at which a wind turbine stops producing power. 4.5 Wind Energy Assessment The wind energy gained from the wind speed frequency distribution in Fig.5 and power curve in Fig.6 is calculated from a summation of the hourly interval of wind speed

4 frequency distribution multiplied by power curve at that wind speed of wind turbine as given in (1). where: 15 E = S n xp n (1) n= 1 E = Wind energy production S = Hourly interval of wind speed frequency distribution P = Power of wind turbine power curve However, the wind speed used for hourly interval in (1) is transformed to (2) because the wind speed was recorded at 4 meters but the hub height of wind turbine preferred is about at 5 meters. Therefore, the wind speed can be estimated by: σ h( x 2) (2) V ( x2) = V ( x1) h( x1) where: V(x 2 ) = Speed transformed to at x 2 meter m/s V(x 1 ) = Speed Recorded at 4 meters m/s h(x 2 ) = Speed measured at x 2 meters in height m h(x 1 ) = Speed measured at 4 meters in height m σ = 1/7 = Therefore, from the wind energy production obtained, CF of the wind energy is 2.55% with total energy production 2,159,319 kwh per year. 5. Feasibility Analysis 5.1 Technical Feasibility To ensure the excellent system reliability and no power quality problems, the system power quality is monitored by using commercial PQ meter at diesel generator bus (23/4 V) within one week. There are two parameters: voltage and frequency investigated because the system is supplied by diesel generation, without harmonic (no electronic interface) according to PEA s power quality standard [6]. However, the harmonic should be analyzed after the wind turbine interconnected to the system if the electronic interface is in use. The voltage and frequency observed is shown in Fig.8 and Fig.9 respectively. From Fig.8, the voltage is in range of PEA s voltage limit ( pu). Similarly, the system frequency monitored is in limit (5 ±.5 Hz), except at the beginning of time, there is an over frequency due to car accident. At the beginning, it would be concluded that the system has a good power quality. The wind energy calculated from (1) and monthly average wind speed is illustrated in Fig.7, which is 12 months of the wind energy productions. It is clear that the wind energy is dependent on the wind speed. For example, in April, the energy is the lowest about 3,7 kwh because the wind speed is very low. On the other hand, the energy generation is the highest in Dec due to the highest wind speed. The capacity factor (CF) is the amount of energy that a facility generates in one year divided by the total amount it could generate if it ran at full capacity [12]. A capacity factor of one implies that the system ran at full capacity for the entire year; a typical wind farm will operate at.25 capacity factor, or 25% [12]. It is calculated form (3) as follow: Figure 8 System Three-Phase Voltage Monitored Within Limits Actual Annual Enery Output CF = Rated Power Output x Operating Time (3) Expected Wind Energy Production Monthly Average Wind Speed Energy (kwh) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Figure 7 Expected Wind Energy Wind Speed (m/s) Figure 9 System Frequency Monitored Within Limits 5.2 Financial & Economic Feasibility Nowadays, the annual system energy produced by diesel generators is around 4,464, kwh. As 1.2 MW wind turbine is supplied to the system, the annul energy generated from the wind turbine is about 2,16, kwh or 662, liters of diesel saving. Besides, it is well known that the rate of CO 2, SO x and NO x emission or air pollutions per kwh from stand-alone diesel generators can vary widely depending on generator type, size, and load

5 factors. The gas emission in case of stand-alone diesel generation and diesel generation including 1.2 MW wind turbine is given in Table 1. It is clear that after the wind turbine is interconnected, the gas emission is decreased dramatically. The annual reduction of CO 2, SO x and NO x is 1685., 97. and 1. ton respectively, which is estimated from the wind turbine generation (2,16, kwh). Because it is a pilot project, the typical value of gas emission from electricity generation is assumed as given below in the table 1, which are the typical value. Table 1 Gas Emissions Case A Case B Case Emission (Ton/Year) Reduction (Ton/Year) CO 2 3,482. 1,685. SO x NO x Remarks: Case A = Stand-alone diesel generation Case B = Diesel generation with 1.2 MW wind turbine where, the emission amount of electricity produced: CO 2 =.78 kg/kwh SO x =.5 kg/kwh NO x =.48 kg/kwh In addition, the assumptions of the financial and economic feasibility analysis are as follows: Discount rate: 11% Project duration: 2 years Three cases are analyzed: Case 1, Case 2 and Case 3, by varying the diesel oil price: 28, 3 and 32 Baht respectively. The key financial and economic data are given in Appendix A Financial Feasibility The financial feasibility analysis is focused on the investment cost and benefit achieved from the diesel saving as the 1.2 MW wind turbine connected to the system. The following investment cost factors of the wind turbine installation are considered: Wind turbine equipment and installation Distribution system upgraded Project management Operation and maintenance In a different way, the benefit of the wind turbine installation is only diesel fuel consumption saving. Moreover, the financial indicators employed to explain the project feasibility analysis are: Financial Internal Rate of Return: FIRR Financial Net Present Value: FNPV Benefit to Cost Ratio: B/C Breakeven Tariff Energy Cost The results of financial feasibility analysis are demonstrated in Table 2. It is seen that in Case3, in which the oil price is 32 Baht with the wind energy generation of 2,16, kwh, the project is feasible to implement. The FIRR and B/C is 11.6% and 1.3 respectively. The energy cost is 3.52 Baht per kwh, which is more than the energy price (3. Baht) controlled by the government. In Case1 and Case2, it is not practical to execute because of the terrible financial indicator. For example, the breakeven point of Case2 is -.11 Baht/kWh meaning that the project can be implemented if a subsidy with.11 Baht/kWh is offered. Table 2 Financial Feasibility Analysis Results Financial Indicators Results Case1 Case2 Case3 Annual Energy (kwh) 2,16, 2,16, 2,16, FIRR (%) FNPV (Baht) -14,47,688-4,578,666 5,25,356 B/C Breakeven tariff (Baht/kWh) Energy Cost / kwh (Baht) It can be concluded that the project can be implemented if the diesel oil price is more than 3 Baht Economic Feasibility Similarly, the economic feasibility is investigated by using the investment cost (excluding VAT and Tax) and benefit obtained from the wind turbine generation, which is the same as financial feasibility analysis. Therefore, the key economic indicators are: Economic Internal Rate of Return: EIRR Economic Net Present Value: FNPV Benefit to Cost Ratio: B/C The important indicators of economic feasibility evaluated are demonstrated in Table 2. It is clear that in this project all cases are feasible to be implemented because the indicators shown are reasonable. For example, the EIRR of case 1, case 2 and case 3 is 13.36, and respectively. They are higher than the discount rate. Besides, the ENPVs are positive value and the B/C ratios are more than 1.. Table 2 Economic Feasibility Study Results Economic Indicators Results Case1 Case2 Case3 Annual Energy (kwh) 2,16, 2,16, 2,16, EIRR (%) ENPV 19,169,314 28,998,336 38,827,358 B/C In these circumstances, it can be concluded that following the economic study of this project, it is feasible to install the wind turbine. 6. Conclusions The paper presents a feasibility study on the installation of a wind turbine in a small island of Thailand. Ko Tao is selected as a case study because it is an attractive place for tourists with environmentally friendly. Moreover, PEA makes a loss on the diesel power generation. The site visit had been conducted to choose the site for wind turbine

6 installation and wind performance monitoring. The results obtained indicated that, the wind energy performance is reasonable to install a wind turbine. After that, the results achieved from technical, financial and economic analysis show that the project is feasible to be implemented. Moreover, the impact of wind turbine on technical: stability, power quality etc. and environmental issues: sound, height, visibility, wildlife, public safety, land use and erosion or on the distribution network should be analyzed thoroughly after finished installation. 7. Acknowledgements This work was supported by the Provincial Electricity Authority (PEA). In addition, the village headmen, Sub- District Administration Organization and villagers at Ko Tao involved are appreciatively acknowledged. References [1] The World Wind Energy Association. 23. Status and Perspective of the Wind Industry: An International Overview. Retrieved January 23, 26 from w.pdf [2] Green, A.M.; Jenkins, N Connection of small wind-turbines in weak grids. IEE Colloquium on Small Wind Power Systems (Digest No. 1996/175). 23 Oct pp 3/1-3/3. [3] Jenkins, N. and Strbac, G Impact of embedded generation on distribution network voltage stability. IEE Colloquium on Voltage Collapse. pp. 9/1-9/4. [4] Turner, A.R.; Sathiakumar, S.; Lee, Y.S. 24. Injecting power from a small wind turbine into a DC bus. PowerCon 24, International Conference on Power System Technology, Vol. 2, Nov 24, pp [5] Driesen, J.; De Brabandere, K.; D'hulst, R.; Belmans, R. 25. Small wind turbines in the built environment: opportunities and grid-connection issues. IEEE Power Engineering Society General Meeting, June 12-16, 25, pp [6] Electricity Generating Authority of Thailand. 23. Green Power: Wind Power. Retrieved January 23, 26 from [7] Provincial Electricity Authority. 2. PEA s regulations for Service Quality. [8] Provincial Electricity Authority. 25. PEA s Diesel Power Generation Data. [9] NRG System, Inc MicroSite Version 2.7 Program. ( [1] Manwell J.F., McGowan. J.G. and Reogers A.L. 22. Wind Energy Explained. London: John Wiley& Sons, Ltd. [11] Intermediate Technology Development Group (ITDG). Wind Electricity Generation. Retrieved November 26, 25 from wind_electricity_generation.pdf [12] Neison, V. and Rohatgi, J.S Wind Characteristic: An Analysis for the Generation of Wind Power. Alternative Energy Institute, West Texas A&M University [13] TEXAS' Renewable Energy Resource. 26. Glossary. Retrieved January 23, 26 from Appendix A Financial and Economic Data Table A.1 Financial Data No. Project Specification &Assumption Factors MW wind turbine cost 56,, Baht 2 Import Taxes 1 % of Equipment 5,6, Baht 3 Wind turbine foundation 12,, Baht 4 Wind turbine transportation 14,, Baht 5 Wind turbine installation 14,, Baht 6 Vat (7%) 6,132, Baht 7 Underground HV. distribution system extension 4,, Baht 8 Overhead HV. distribution system extension 4,5, Baht 9 Transformer and installation 1,5, Baht 1 Distribution system upgraded 1,, Baht 11 Diesel generator efficiency 3.5 kwh/l 12 Fuel saving from excess electricity reduction 615,4 L 13 Project management - Year1 2,887,2 Baht 14 Project management - Year2 3,729,2 Baht 15 Project management - Year3 1,51,6 Baht 16 Annual Maintenance.4 Baht/kWh 17 Annual output from wind turbine 2,16, kwh 18 Annual output diesel generation 2,325,5 kwh 19 Annual maintenance cost increase 2.5 %

7 Table A.2 Economic Data No. Project Specific &Assumption Factors MW wind turbine cost 56,, Baht 2 Wind turbine foundation 12,, Baht 3 Wind turbine transportation 14,, Baht 4 Wind turbine installation 14,, Baht 5 Underground HV. distribution system extension 4,, Baht 6 Overhead HV. distribution system extension 4,5, Baht 7 Transformer and installation 1,5, Baht 8 Distribution system upgraded 1,, Baht 9 Annual Maintenance.4 Baht/kWh 1 Annual output from wind turbine 2,16, kwh 11 Annual output diesel generation 2,325,5 kwh 12 Diesel generator efficiency 3.5 kwh/l 13 CO2 Emission / kwh of Diesel Generation.78 kg/kwh 14 SOx Emission/kWh of Diesel Generation.5 kg/kwh 15 NOx Emission/kWh of Diesel Generation.48 kg/kwh 16 Ton of CO2 Reduction 1,684.8 Ton 17 Ton of SOx Reduction 97.2 Ton 18 Ton of NOx Reduction 1.37 Ton 19 Unit Cost of CO2 Reduction.63 Baht/kWh 2 Unit Cost of SOx Reduction.5 Baht/kWh 21 Unit Cost of Nox Reduction.14 Baht/kWh 22 Fuel saving from Excess electricity reduction 615,4 Liter 23 Project Management - Year1 2,887,2 Baht 24 Project Management - Year2 3,729,2 Baht 25 Project Management - Year3 1,51,6 Baht 26 Annual Maintenance Cost Increase 2.5 %