Evaluation of a Wind Farm Project for a Smart City in the South-East Coastal Zone of Mauritius
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Evaluation of a wind farm project for a smart city in the South-East Coastal Zone of Mauritius A.Z. Dhunny M.R. Lollchund* S.D.D.V. Rughooputh Department of Physics, University of Mauritius, Reduit, Mauritius Abstract 1. Introduction A study was carried out to analyse the potential of Energy is the basis of the world’s economy, combin - wind energy in the generation of electricity for a ing with all other entities that are vital for smart city which is located in the South-East Coastal economies. The quest to meet growing energy Zone of Mauritius. A flat land area of 10 square km demand of the global population initiated numer - situated about 3.5 km from the smart city was cho - ous research in a wide range of environmental sen for the placement of a wind farm. The viability application of renewable energy (RE) (Park & Law, of the location was assessed by analysing ten years 2015). Currently, the wind sector stands out as one (Jan 2005 to Dec 2014) of mean hourly wind speed of the most promising RE as wind is an inex - measured at a height of 10 m above ground level haustible diurnal resource that can provide signifi - (m.a.g.l). The speed data was filtered according to cant quantities of energy to support the needs of a the AWS (1997) guidelines and computed at 60 country (Ackerman & Soder, 2002). Exploitation of m.a.g.l using the power law formula. At this height, wind energy for the production of electricity the average wind speeds was approximately 6.5 increased around the world at an accelerating pace m/s, which was considered cost effective, as per the more than ten 10 years ago (Marciukaitis et al ., European Wind Energy Union guidelines for the 2008). Wind energy is currently being exploited harvesting of wind power. Estimated yearly power widely in many countries such as the USA, generated by a wind farm consisting of 40 wind tur - Germany, Spain, China, India, UK, Denmark and bines, each of rating capacity 275 kW, placed at a Canada (Adelaja et al ., 2012; Coskun & Turker, hub height of 60 m were made. The study resulted 2012). According to the American Wind Energy in an investment proposal for a 11 MW wind farm Association (AWEA) and the European Wind project in Mauritius. Energy Association (EWEA), cumulative global wind energy generating capacity exceeded 282 GW Keywords:wind energy assessment, two-parameter in 2012, with an increase of about 80% of new weibull distribution, wind power, wind turbines capacity that was installed worldwide during the past decade (WEC, 2014). Such a vast RE resource has a potential to be exploitable by small island developing states (SIDS) such as the island of Mauritius. The work of Dhunny at al. (2015) showed the potentials of wind energy for Mauritius at different locations comparable with those of countries already reaping the benefits of this tech - nology. * Corresponding author An accurate wind resource assessment is an Email: [email protected] important and critical factor to be well understood Tel: + 230 4037669 for harnessing the power of the wind (Marciukaitis DOI: http://dx.doi.org/10.17159/2413-3051/2016/v27i1a1565 et al ., 2008). The identification of potential areas 39 Journal of Energy in Southern Africa • Vol 27 No 1 • February 2016 that might be suitable for the development of wind Altunkaynak et al ., 2012). Moreover, by finding the projects are enhanced by accurate wind resource shape parameter and scale factor of the Weibull dis - data available at specific chosen locations (Radics tribution that represents the wind speed data, direct & Bartholy, 2008). In its budget speech for the estimates of the expected wind power can be made financial year 2015-2016, the Government of (Mirghaed & Roshandel, 2013). During the last Mauritius clearly indicated its vision to build up decade, research was undertaken on the wind char - eight 8 smart cities throughout the island. These are acteristics and wind power potential in many coun - Omnicane Mon-Tresor Airport City in the South tries around the world (Tarkowski & Uliasz-Misiak, East Coastal Zone, St-Felix Village Project in the 2003). Examples include Tunisia (Zghal et al ., South, Medine Integrated Park in the West, Azuri 2011), eastern Mediterranean (Sahin et al ., 2005), phase 2 and Terra Projects in the North, Riche-Terre Turkey (Gokcek et al ., 2007a; Ucar & Balo, 2009b) and Highlands Project in the centre and Roches- Nigeria (Ngala et al ., 2006), Iran (Keyhani et al ., Noires in the North-East Coastal Zone. The smart 2010), Columbia (Jimenez et al ., 2011), Egypt cities are expected to produce a significant amount (Shata & Hanitsch, 2006), Kuwait (Al-Nassar et al ., of the energy of their own using RE sources such as 2007), coastal areas of Jiwani, Pakistan(Lehri et al ., solar and wind. In this work, the potential of wind 2013) and Greece (Kaldellis, 2002) among others. energy was assessed for one of the smart cities, the Omnicane Mon Tresor Airport. The placement of a 2.1 The Weibull PDF potential wind farm is also analysed along with the Knowledge of the wind speed frequency distribu - expected power output yielded at that location to tion plays an important role for the estimation of furbish the smart city as well as the project costing wind potential in any location (Azad et al ., 2014). in terms of initial investment and expected return When the distribution of wind speed is known, both on investment. the wind power potential and economic viability of Section 2 discusses the wind assessment method the site can be calculated. The two-parameter utilised. Section 3 describes the general wind flow Weibull distribution ƒ( v), most commonly known patterns over Mauritius, as well as the site of interest for its high accuracy for wind speed data analysis where data was collected for this study. In Section (Zghal et al ., 2011), is expressed as Equation 1. 4, the main results obtained are analysed and dis - cussed. Section 5 enumerates the project cost and Section 6 outlines the main conclusions of this (1) work. 2. Wind energy assessment where c is the Weibull scale parameter (same The assessment of wind energy potential of a region dimension as ), which indicates the wind regime at requires long term data related to the wind speed that location and k is a dimensionless Weibull shape and an accurate determination of its distribution. parameter (Abed & El-Mallah, 1997). The cumula - The variations in wind speed can be characterised tive distribution function F(v), which is the integral by two functions, namely,the probability density of ƒ( v) in the range of (0, v), is expressed according function (PDF) and the corresponding cumulative to Equation 2. density function (CDF). In literature, the wind speed frequency distribution for a given location was rep - (2) resented by different and various PDFs such as Burr, Weibull, Lognormal, Normal, Rayleigh, Gamma and Frechet (Kollu et al ., 2012; Morgan et The mean and variance are respectively given al .,2010; Abbas et al ., 2012; Masseran et al ., 2013). by Equations 3 and 4: Dhunny et al . (2014) performed a statistical analy - sis on the wind speed data of the two meteorologi - cal stations, Plaisance and Vacoas. The authors (3) undertook to fit their data with these PDFs and compared the results using the Chi-Square, Kolmogorov and Anderson-Darling goodness-of-fit (4) tests. The results indicated that both sets of wind speed data were more significantly represented by where is the gamma function. To estimate the the Weibull and Burr distributions. For this study, parameters k and c for a given set of measured the Weibull distribution was solely considered. A velocity data, numerous methods were proposed in review of the wind assessment literature revealed the literature (Mann et al ., 1974). The most com - that the Weibull PDF fits most accurately a variety mon one is the Maximum Likelihood Estimation of wind speed data measured at different geograph - (MLE), of which details about the method is found ical locations in the world (Carta et al ., 2009; in the work of Harris & Stocker (1998). 40 Journal of Energy in Southern Africa • Vol 27 No 1 • February 2016 2.2 Wind speed variation with altitude energy output of the wind turbine is given by As wind turbine can be placed at different heights, Equation 10. the wind speed data need to be measured at such heights by using the power law which is one of the (10) most accepted expression in the literature (Zekai Sen & Erdik, 2012). This law describes the vertical variation of wind speed and represented by where Nh is the number of hours in a year and vin Equation 5. and vout are the cut-in and cut-off wind speeds of the turbine respectively (Jimenez et al ., 2011). (5) 2.4 Turbulence The dissipation of the wind’s kinetic energy into where v(h) is the wind speed at the hub height h, thermal energy causes turbulence in the wind. v0 is the wind speed at measured height and , Turbulent wind have a moderately steady mean wind shear power law exponent. The value for over time periods of approximately an hour. But varies from 0.1 over the tops of steep hills to 0.25 over short times it has quite a big disparity. in sheltered locations. For flat coastal regions, is Turbulence can be considered as the arbitrary wind taken as 0.143 (1/7), which is the typical value used speed fluctuations imposed on the mean wind in most research (Youm et al ., 2005). speed, which occurs in all three 3 directions: longi - As the wind velocity varies with height, it is evi - tudinal, tangential and vertical.