Fuzzy Logic Based Multi-Criteria Wind Turbine Selection Strategy—A Case Study of Qassim, Saudi Arabia
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energies Article Fuzzy Logic Based Multi-Criteria Wind Turbine Selection Strategy—A Case Study of Qassim, Saudi Arabia Shafiqur Rehman 1 and Salman A. Khan 2,* 1 Center for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; [email protected] 2 Computer Science Department, University of Pretoria, Pretoria 0002, South Africa * Correspondence: [email protected]; Tel.: +27-12-420-2361 Academic Editor: Frede Blaabjerg Received: 20 July 2016; Accepted: 22 September 2016; Published: 26 October 2016 Abstract: The emergence of wind energy as a potential alternative to traditional sources of fuel has prompted notable research in recent years. One primary factor contributing to efficient utilization of wind energy from a wind farm is the type of turbines used. However, selection of a specific wind turbine type is a difficult task due to several criteria involved in the selection process. Important criteria include turbine’s power rating, height of tower, energy output, rotor diameter, cut-in wind speed, and rated wind speed. The complexity of this selection process is further amplified by the presence of conflicts between the decision criteria. Therefore, a decision is desired that provides the best balance between all selection criteria. Considering the complexities involved in the decision-making process, this paper proposes a two-level decision turbine selection strategy based on fuzzy logic and multi-criteria decision-making (MCDM) approach. More specifically, the fuzzy arithmetic mean operator is used in the decision process. The proposed approach is applied to wind data collected from the site of Qassim, Saudi Arabia. Results indicate that the proposed approach was effective in finding the optimal turbine from a set of 20 turbines of various capacities. Keywords: wind turbine; wind energy; fuzzy logic; decision-making; fuzzy arithmetic mean operator 1. Introduction Renewable sources of energy such as wind, solar photovoltaic, solar thermal, geothermal, biomass, municipal waste, tides and waves, and small and large hydro are being used globally to combat the deteriorating climatic conditions, and at the same time meeting the growing demand for energy. The renewable sources of energy are independent of the location and hence can be tapped anywhere, and can provide energy to people living in remote areas which are not connected to the grid. Of these clean and freely available sources of energy, wind has been accepted commercially [1–3] due to ease of installation, operation and maintenance, and availability of advanced wind turbines of all sizes from few kilowatts to multi-megawatt. It is easy and fast to deploy wind turbines requiring minimal attention. Furthermore, these turbines have a life span of 20 to 25 years. Beside all technical and commercial advantages, wind power harnessing does not need any kind of transportation and does not have geographical boundaries [4,5]. In recent years, wind power generation has emerged as the fastest growing source of energy on global scale. A recent report from Global Wind Energy Council (GWEC) [6] states that the cumulative global wind power installed capacity reached 432,419 MW at the end of 2015 compared to 17,400 MW in year 2000, showing an increase of about 2485.2% in a period of 16 years as depicted in Figure1. The cumulative installed capacity increased from 369,695 MW in 2014 to 432,419 MW in 2015, which is approximately 17%. China leads the global share with addition of 30,500 MW capacities Energies 2016, 9, 872; doi:10.3390/en9110872 www.mdpi.com/journal/energies Energies 2016, 9, 872 2 of 26 Energies 2016, 9, 872 2 of 25 in 2015. This was followed by the United States, Germany, Brazil, and India, which added 8598, 6013, 2754,This andwas 2623followed MW by capacities, the United States, respectively. Germany, The Brazil, situation and India, in Africa which andadded the 8598, Middle 6013, 2754, East is slow but improving,and 2623 withMW capacities, South Africa, respectively. Ethiopia, The and situation Jordan in addingAfrica and 483, the 153, Middle and East 117 MW,is slow respectively, but improving, with South Africa, Ethiopia, and Jordan adding 483, 153, and 117 MW, respectively, bringing the total to 753 MW. bringing the total to 753 MW. 500 432 400 370 318 283 300 238 194 200 158 121 74 94 100 48 59 17 24 31 39 0 Installed capacity, (GW) Installed capacity, Year Figure 1. Global cumulative wind power installed capacities [6]. Figure 1. Global cumulative wind power installed capacities [6]. Although the wind power technology is simple and extraction of power from wind is easy, there Althoughare some the challenges wind powersuch as technology maximizing isthe simple output andfrom extraction the wind turbines of power and from maintaining wind is easy, there areuninterrupted some challenges power due such to intermittent as maximizing and fluctuating the output nature from of the the wind. wind The turbines wind speed and is highly maintaining site dependent, and changes with time of the day, day of the year, height above ground level (AGL), uninterruptedand topography. power due Usually, to intermittent the wind speed and measurements fluctuating nature are made of theat 8 wind. to 12 m The AGL, wind whereas speed the is highly site dependent,hub heights and of changesthe modern with wind time turbines of the of day,multi day megawatt of the capacities year, height vary from above 80 groundto 120 m. level Hub (AGL), and topography.height refers Usually, to the height the wind of the speed tower measurements at which the turbine are made rotor is at installed 8 to 12 mto harness AGL, whereas the wind the hub heightswhich of the can modern then be wind converted turbines to energy. of multi The megawatt hub height capacities cannot exceed vary a from threshold 80 to value 120 m. due Hub to height refers totechnical, the height installation, of the economical, tower at which and maintenance the turbine issues. rotor Hence, is installed it is important to harness to have an the accurate wind which knowledge of the suitable hub height for a particular location and for a particular type of wind can then be converted to energy. The hub height cannot exceed a threshold value due to technical, turbine for maximum energy output from wind turbines [6]. installation,In economical, general, as the and wind maintenance speed increases issues. with Hence, height, it isthe important energy output to have from an the accurate turbine knowledgealso of the suitableincreases. hub Therefore, height for for increased a particular wind energy location output and from for a selected a particular wind turbine, type ofthe wind hub height turbine for maximumshould energy be as output high as from possible, wind both turbines economically [6]. and technology wise. However, the hub height Incannot general, be increased as the wind randomly. speed This increases implies that with the height, two decision the energy criteria outputof hub height from and the energy turbine also increases.output Therefore, are conflicting for increased in nature, wind and it energy is not possible output to from optimize a selected both criteria wind at turbine, the same thetime. hub In height addition to these factors, other factors specific to the turbine such as rotor diameter, cut‐in wind speed should be as high as possible, both economically and technology wise. However, the hub height cannot and rated wind speed contribute to the energy extraction. However, many of the aforementioned be increasedfactors randomly. are conflicting This with implies each other: that improving the two one decision factor negatively criteria of affects hub heightthe others. and Moreover, energy output are conflictingthere is no in direct nature, or indirect and it is proportional not possible relationship to optimize between both some criteria of these at thefactors, same which time. further In addition to theseadds factors, to difficulty other factors in choosing specific a suitable to the turbine. turbine For such example, as rotor some diameter, turbines cut-inhave bigger wind rotor speed and rated winddiameters, speed which contribute is desired to due the to energy larger swept extraction. area and However, hence more many power. of Wind the aforementioned turbines with low factors are conflictingcut‐in and with rated each wind other: speeds improving are required one for higher factor wind negatively energy productions affects the and others. are more Moreover, suitable there is at low windy sites. no direct orA indirect possible proportional approach to select relationship the best turbine between in presence some of of aforementioned these factors, conflicting which further factors adds to difficultyis to in opt choosing for a solution a suitable that would turbine. provide For an example,optimal balance some between turbines the all have factors bigger (also rotortermed diameters, as which isdecision desired criteria). due to An larger approach swept following area and this hencerationale more was proposed power. Wind in various turbines studies with [4,7,8], low which cut-in and rated windwas based speeds on are multi required‐criteria decision for higher‐making wind (MCDM) energy and productions utilized fuzzy and logic are to more find suitablethe best at low windy sites.balance between two criteria, i.e., hub height and rated power output/zero power output. The underlying fuzzy function to reach the decision was based on the Unified And‐Or (UAO) operator A possible approach to select the best turbine in presence of aforementioned conflicting factors is to opt for a solution that would provide an optimal balance between the all factors (also termed as decision criteria). An approach following this rationale was proposed in various studies [4,7,8], which was based on multi-criteria decision-making (MCDM) and utilized fuzzy logic to find the best balance between two criteria, i.e., hub height and rated power output/zero power output.