ISSN 2321 3361 © 2019 IJESC

Research Article Volume 9 Issue No.8 Site Suitability Analysis for Locating Wind Energy Power Plant in , using Geospatial Technology Okechukwu, U.C1, Igbokwe, J. I2, Ejikeme, J. O3 Department of Surveying and Geoinformatics Nnamdi Azikiwe University, Awka Anambra State, Nigeria

Abstract: Energy is the driving power for the development of any economy. Most of the energy sources are generated from fossil fuels and with the advent of Industrial Revolution, the demand of energy from fossil fuels continues to grow. It has become evident that energy generated from these fossil fuels has led to high concentrations of harmful gases leading to environmental damage. And despite the abundance of energy resources in Nigeria, the country is still in short supply of electrical power. There is therefore the need to direct resources to harnessing renewable energy resources such as wind energy for an alternative power supply in Nigeria and especially in Rivers State. The aim of this research was to perform site suitability analysis for locating wind energy power plant in Rivers State, Nigeria using geospatial technology. One of the major challenges for suitable location of wind energy power plant is in the site selection. This decision of site selection consists of many factors and criteria. Using Geographic Information System (GIS), a multi- criteria approach model was developed to identify areas that are best suited for locating wind energy power plant. Seven criteria were adopted in this research. Using Analytical Hierarchy process the evaluation of these criteria was performed. Each of these criteria was assigned a score of importance. Weights were also assigned to these criteria using pair wise comparison. Using suitability calculator in Arc GIS environment the sites with the highest suitability for wind energy power plant was generated. The outcome of the suitability analysis satisfied all the constraints in the criteria and the results revealed five potential locations for siting wind energy power plant in Rivers State.The results show that this approach is capable of identifying locations highly suited for wind energy development and could also help in identify suitable locations for wind energy in other areas.

Keywords: Wind, Wind Energy, Geospatial Technology, Multi Criteria Analysis, Remote Sensing.

1.0. INTRODUCTION Energy supplied from the fossil fuel and natural gas stations are not friendly to the environment (Cavallaro, 2010), because of its Nigeria is richly blessed with abundant fossil fuels (crude oil and harmful emissions and by products, they are also depletable, gas). These fossil fuels which account to over 90% of Nigeria’s radioactive and do not produce adequate and consistent power foreign income earnings have also been the major source of for the nation’s consumption, even the cost of maintenance has electricity generation in the country(Ajayi,2009).This energy is never been of help too (Bartnicki and Willamson, 2012). The generated from different hydro-power station and thermal power finite nature of fossil fuel reserves, fluctuating price of crude oil station. About 79% of electricity generation in Nigeria comes in the international market, growing demand for carbon from thermal power plant and 21% comes from hydro power footprints reduction and the quest by several world economies to station. The supply of electrical energy in Nigeria has been from generate energy from green energy resources will impinge on the Power Holding Company of Nigeria (PHCN). It expands country’s income earnings from fossil fuels in the nearest future annually in order to meet the ever-increasing demand of energy (Akhator, Obanor&Sadjere, 2019). There is therefore the need to consumption in Nigeria. Despite the abundance of fossil fuels for harness renewable energy potential such as wind, solar, for energy generation and PHCN been expanded annually to meet reliable power supply in the country, as they contain enormous, the demand of energy consumption in Nigeria, electric power largely untapped and sustained opportunity for meeting the supply has never met the demand for energy consumption in the world’s energy need. They are environmentally friendly as they country. This is as a result of the Government poor investment in do not contribute harmful and toxic emission to it.One of the power generation and maintenance, inadequate supplies of major technical challenges to wind energy development is to natural gas from various gas wells of the nation most especially locate the areas with high suitability for placing wind power in Niger Delta and seasonal dependent of the hydro-power plant. Selecting the site for wind energy power plant positions is station. This has compelled Nigerians to the private use of a complex process involving not only technical requirement, but alternative power generation through the use of diesel and petrol also physical, economic, social, environmental and political generators to meet their daily needs. The emissions from these requirements that may result in conflicting objectives. Such generating sets have caused a lot of environmental impact in complexities necessitate the simultaneous use of several decision terms of global warming, gradual depletion of the ozone layer, support tools such as high spatial resolution remotely sensed pollution and health hazards. These impacts have also been data, Geographical Information System (GIS) and Multi Criteria subjects of critical global discussion because they release a lot of Decision Making (MCDM). For example, Tegou, Polatidis and greenhouse gases to the atmosphere (Agbetuyi, et al, 2013). Haralambopoulos (2010) combined multi criteria analysis

IJESC, August 2019 23476 http://ijesc.org/ (MCA), AHP with GIS to find the suitable areas for wind energy ii. Slope development on the Greek island of Lesvos. In this research, The slope was another criterion in the appropriate functioning of they used a set of environmental, economic, social, and technical a wind power plant and its installation. Areas with steep slopes constraints, based on recent Greek legislation to identify the are generally considered less suitable, because of the extra costs potential sites for wind power installation. Furthermore, the area of construction and maintenance. They create undesirable wind under consideration is evaluated by a variety of criteria, such as turbulence, decrease accessibility through roads and increase wind power potential, land cover type, electricity demand, visual construction costs (Chaudhry, 2008).The constraint used to impact, land value, and distance from the electricity grid. define the technical requirement for slope is that the slope of the Similarly, Chikotoet al, (2015) in their work applied a GIS-based site should be greater than 8 degrees but less than 15 degrees. Analytic Hierarchy Process approach, where a group of local This will place the site in a terrain range suitable for maximizing experts is asked to pair-wise compare the incorporated criteria in the wind resource. order to derive the relative importance of each criterion. Ovu (2018) also carried out a research on the site suitability location iii. Elevation of wind farm in Edo State, Nigeria using overlay analysis in For efficient energy generation, wind power plant must be GIS. He used the following criteria; wind speed, land-use/land- located in open areas and on higher elevations than the cover, slope, proximity to road, town and transmission network surrounding area, preferably, elevations greater than 100 m. This to achieve the desire result. Thus, finding suitable locations for constraint will obviously depend in part on the relative height of wind power installation becomes critical for the economic the landscape. a minimum height of 40m was used to carry out success of wind energy operation. This research gives a the modelling. comprehensive set of factors and condition for site suitability of wind energy power plant in Rivers state using geospatial iv. Proximity to Road Network analysis. It was also necessary to confirm that road access is available, or can be developed at a reasonable cost, for transporting the 2.0 MATERIALS AND METHODOLOGY turbines and other equipment. This will generally mean that the site must be within a minimum distance from the national road 2.1 Study Area network.(Chaudhry,2008) suggested a distance of 2.5 km from The study area Rivers state is located in south-south geopolitical main roads and railroads and a distance of 500 meter from zone of Nigeria, which lies between latitudes 4° 44′ 59″ N and secondary roads. So, the criterion used was to determine area 4° 58′ 11.91″ N and longitudes 6° 49′ 39″ E and 7° 01′ 14.34″ E. within 2.5km from road networks so as to allow access to Rivers State is on an elevation of 20m above the mean sea level. potential sites. Rivers state was created out of the old Eastern Region in 1967 with its capital in . Rivers state is covering a total v. Proximity to Towns of 11,077 sq km land area with 23 (twenty-three) Local Wind power plant near towns can cause negative impacts on the Government Area. It is bounded in the south by Atlantic Ocean, local population. A suitable distance from the population centers in the north by Anambra, Imo and Abia states, in the east by is of importance due to some reasons: the noise pollution of Awka Ibom state and in the west by Bayelsa and Delta states. wind turbines and the unpleasant effect of shadow flickers on dwellers, reduction of wind speed and development of future 2.2 Site Selection Criteria for Wind Energy Power Plant residential sections. In order to minimize negative impacts on the In site selection of wind power plants, a comprehensive set of environment it is recommended that wind power plants are at the criteria and factors were required and as the number of these greatest possible distance (2.5km) from town areas. criteria in a model increases, it requires a more accurate output, but considering the inaccessibility to entire interfering vi. Proximity to National Grid information in the site selection and existing limitations, the A suitable location will need to be in close proximity to existing most effective and most essential factors and criteria were grid lines to minimize production costs. The distance to these selected. The criteria selection was done through a transmission lines is a necessity in order to transport the energy comprehensive literature review and was then stream down to created by the wind turbines and reduce costs therefore a crucial those criteria critical and relevant for the site suitability of wind technical consideration is done to link up renewable energy energy power plant. These criteria are necessary, due to the source as much as possible into the existing energy network. So, impact the wind turbines may have on the existing land uses, the criteria used were to identify areas that are within 2 environment and communities. kilometre of Transmission network and by extension existing energy/power networks. i. Wind Speed The most important criterion in selecting a wind energy power vii. Land-use/Land-cover mapping plant location was the wind speeds because the availability of Land use is one of the most important factors for energy wind speed is paramount for the use of electricity generation. investments. Wind energy should be installed in the area in The wind speed initiates with efficiency and halting speed of which they negligibly interfere with existing land use. Land use most of the wind turbines are 3 and 25 meters per second affects the decision of wind power plant in that there are some respectively. A good Wind speed considered were speeds equal cases where no wind power plants can be built although to or greater than 3.5 meters per second. Therefore, first thing sufficient wind speed are detected such as forest area, wetlands first was to eliminate all sites that are not expected to have a aviation zone archaeological site, etc. Grasslands and bare lands sufficient wind speed of 3.5m/s. are highly preferred. So, the criteria used was to bare lands and grasslands within the study area, while eliminating the other

IJESC, August 2019 23477 http://ijesc.org/ land-cover classes i.e. suitable land-cover/Land-use either forest criterion used was to determine areas 2.5km away from all water and barren land measuring up to at least 2Km by 2Km in area. courses. viii. Water Pollution As a potential variable affecting wind farm location, as well as 2.3 Data Used lessening the risk of flooding of the wind farm or polluting The data used for this study as well as their sources are listed in surface and ground water, it is important to keep the site and the Table 2.1. Most of these datasets were obtained from already various mechanical parts of the turbines away from water. The existing medium.

Table.2.1. Data and their sources Data Data Source Slope SRTM Dem (Earthexplorer.usgs.gov) Wind Speed Ncdc.noaa.gov Land Cover/ Land Use Land sat 8 OLI (Earthexplorer.usgs.gov) Distance to Transmission Line Greater Port Harcourt City Development Authority (GPHCDA).

Distance to Road Ministry of land and Survey Rivers State.

Proximity to Towns Ministry of land and Survey Rivers State.

Proximity to Water body Greater Port Harcourt City Development Authority (GPHCDA).

Exclusionary Areas (Airport) Greater Port Harcourt City Development Authority (GPHCDA).

2.4 Modeling Procedure buffer around towns were considered suitable for proximity to For the study modeling, multi-criteria analysis based AHP towns. method was used. All of the criteria with vector datasets (proximity to road, town, transmission line and water body) were 2.4.1Development of the Pair-wise Comparison Matrix first converted to Boolean buffer raster. Reclassification of all Pair-wise comparisons are fundamental in the use of the AHP to the criteria was done to get the most suitable areas of the criteria. determine relative importance of each criterion. The pair-wise Wind speeds were reclassified and any area greater than 3.5m/s comparison method was based on a comparison within a were considered suitable and less than 3.5m/s are unsuitable. reciprocal matrix, in which the number of rows and columns are Grassland and bare lands were considered suitable when it defined by the number of criteria. Accordingly, it is necessary to comes to land use while forest, rivers and urban areas were establish a comparison matrix between pairs of criteria, considered unsuitable. Slope areas between 80 and 150 were contrasting the importance of each pair with all the others, thus considered suitable while less than 80 and greater than 150were generating a pair-wise comparison matrix. The comparison considered unsuitable. Areas buffered 2km around road ratings are provided on a nine-point continuous scale (Saaty, networks, transmission lines were considered suitable for 1990). Table 2.2, shows the pair-wise comparison of the criteria. proximity to road networks and transmission lines while 2.5km

Table.2.2. Pair-wise Comparison of the Evaluated Criteria Criterion Wind speed Slo Landcover Distance to Distance to Proximity Distance to pe /Landuse Transmission Road to Towns Water body Line Wind speed 1 2 3 4 5 5 9 Slope ½ 1 3 5 6 6 7 Land cover 1/3 1/3 1 5 6 6 7 /Land use Distance to ¼ 1/5 1/6 1 2 3 4 Transmission Line Distance to 1/5 1/6 1/6 ½ `1 2 3 Road Proximity to 1/5 1/6 1/6 1/3 ½ 1 4 towns Distance to 1/9 1/7 1/7 ¼ 1/3 ¼ 1 Waterbody Total 2.59 4.0 11.5 16 20.8 23.25 35

IJESC, August 2019 23478 http://ijesc.org/ 2.4.2 Computation of criteria weights A pair-wise matrix for the estimation of the weights of the criteria is created and shown in table 2.3

Table.2.3. Relative Weight of Criteria Criterion Wind speed Slope Landover/ Distance to Distance Proximity Distance to Relative Land use Transmission to Road to Towns Water body Weight Line Windspeed 0.39 0.5 0.26 0.25 0.24 0.22 0.26 0.30 Slope 0.19 0.25 0.26 0.31 0.28 0.25 0.2 0.25 Landcover/ 0.12 0.08 0.08 0.31 0.28 0.25 0.2 0.19 Landuse Distance to 0.09 0.05 0.01 0.06 0.09 0.12 0.11 0.07 Transmission Line Distance to 0.07 0.02 0.01 0.03 `0.04 0.08 0.08 0.047 Road Proximity to 0.07 0.02 0.01 0.02 0.02 0.04 0.11 0.041 towns Distance to 0.04 0.03 0.01 0.01 0.01 0.01 0.03 0.02 waterbody

2.4.3 Estimation of the Constituency Ratio determine the suitable locations for wind energy power plant in The consistency ratio (CR) is design in such a way that if Rivers State. The locating of this wind energy power plant was CR<0.10, the ratio indicates a reasonable level of consistency in done through the use of criteria selected from different data the pair-wise comparisons; if, however, CR ≥ 0.10, the values of sources. MCDM base on AHP approach was adopted to solving the ratio are indicative of inconsistent judgments. From the the problem of the conflicting criteria used and its ability to judgment a Consistency Ratio (CR) of 0.089 was achieved check for inconsistence of the decision makers. which was less than the maximum allowable ratio of 0.1. The total evaluation map was calculated by using raster calculator in ArcGIS 10.5. The criteria were standardized to a continuous scale of suitability from the least to the most suitable, thus giving flexibility in the site selection.

The weighted linear combination equation is the following:

S = ((F1 * 0.4) + (F2 * 0.25) + (F3 * 0.19) + (F4 * 0.07) + (F5 * S0.047) = Σ푤푖푥푖 + (F6 x Π* 푐푗0.041)+ (F7 * 0.02)). The output presented potential sites with the highest suitability for Wind Energy Farm in Rivers State.

3.0 RESULT AND DISCUSSION

The results revealed five potential locations for locating Wind Energy Power Plant (see figure 3.0). The first site is located at in Emohua LGA with an area of 423 hectares, second site is located at Elele in Ikwerre LGA with an area of 411 hectares, the third site is located at Egbeda in Ogba-Egbema- Ndoni LGA with an area of 401 hectares, the fourth site is located at Obibi in LGA with an area of 714 hectares and the last site is located at Umuakpo in LGA with an area of 412 hectares, bring it to a total of 2361 hectares of potential sites for siting Wind Energy Farm in Rivers State. The sites selected were 2.5km away from the settlement zone, on a gentle slope between 8 and 15 degrees, 2.5km away from any Figure.3.0. Suitable Sites for locating wind energy power water courses and wetlands and within 2km of the road networks plant in Rivers State for accessibility, within 2km of power lines, on locations with at least 3.5m/s wind-speed and on either open spaces or grasslands. 4.0 CONCLUSION AND RECOMMENDATION The main considerations were safety, accessibility, economy and the environment and therefore satisfied the criteria for locating Wind energy power plant site selection can be accomplished by Wind Energy Power Plant the stud area. In this study, multi spatial decision typically involving a large set of feasible criteria decision making approach base on AHP was used to alternatives. The GIS base multi criteria decision making

IJESC, August 2019 23479 http://ijesc.org/ approach as a decision-making tool, being facilitated, combined Case Study of Nyanga District. Ethiopian Journal of various information layers as well as implementing the necessary Environmental Studies & Management. 8(4), 351 – 363. analysis on the data, although the GIS methodology makes the decision-making process more objective, there is still an element [7]. Clarke, K. C. (1986). Advances in Geographic Information of subjectivity associated with the allocation of map weights and Systems, Computers, Environment and Urban Systems. 10, 175- scaling. The site selection was based on seven different criteria 184. to analyze the suitable locations for wind energy power plant development. These criteria include wind speeds, land use, [8]. Ovu, I. (2018). Site suitability analysis for wind farm in Edo proximity to town and water body, proximity to major roads, State, Nigeria using geospatial technology. Unpublished MS.C slope and transmission lines. Weights were also assigned to Thesis. Department of Surveying and Geoinformatics, Nnamdi these criteria layers using AHP pair-wise comparisons. Finally, a Azikiwe University, Awka. consistence ratio was calculated. The study was able to apply spatial decision making in using the different criteria available to [9]. Saaty T. l. (1990). A scaling method of priorities in ascertain the suitability of potential site where wind energy hierarchical structures. Journal of Mathematical psychology, 15 power plant can be located within Rivers State. The study (3), 234-281. located five sites satisfying all criteria where wind energy power plant could be sited and these areas covers a total of 2361 [10]. Tegou, L. I., Polatidis, H., &Haralambopoulos, D. A. hectares, with all sites satisfying and exhibiting the best balance (2010). Environmental management framework for wind farm between all established criteria. It was then recommended that: siting: Methodology and case study, Journal of Environmental Management. 91 (11), 2134 2147. i. The accuracy of the selected location could be improved by – incorporating a wind data set with more sample locations concentrated within the study area, rather than points interpolation. ii. It is recommended that land use and ownerships of the selected area should be investigated before placing the wind energy power plant. iii. Finally, it is recommended that soil data (soil structure and stability) be looked at as a criterion, as building wind power plant foundations on weak soils will pave way for environmental problems like erosion in the study area.

5.0. REFERENCE

[1]. Ajayi, O. O. (2009). Assessment of utilization of wind energy resources in NigeriaMechanical Engineering Department, Covenant University, P.M.B. 1023, Ota, Ogun State, Nigeria Energy Policy. 37, 750–753.

[2]. Akhator, P. E., Obanor, A. I., &Sadjere, E. G. (2019). Electricity situation and potential development in Nigeria using off-grid green energy solutions. J. Appl. Sci. Environ. Manage. Vol. 23 (3) 527-537

[3]. Agbetuyi, A.F., Odigwe, I. A., Awelewa, A. A., &Awosope, C. O. A. (2013). Wind power potential andintegration in Africa. Department of Electrical and Information, College of Science & Technology, Covenant University, Canaanl and, Ota, Ogun State, Nigeria International Journal of Development and Sustainability 2(1), 232-239

[4]. Bartnicki, N., &Willamson, M. (2012). An Integrated GIS Approach to Wind Power Site Selection in Huron County, Ontario. Department of Geography, University of Guelph, Guelph

[5]. Chaudhry, R. (2008). Using Multi-Criteria Evaluation to Determine Suitable Sites for Developing Wind Farms in Massachusetts, Project Report, Clark University, Worcester, USA (pp. 16).

[6]. Chikoto, M., Gwenzi, J., Maruziva, R., & Buka, L. T. (2015). Mapping Suitable Sites for Setting up Wind Farms: A

IJESC, August 2019 23480 http://ijesc.org/