PROSPECT OF WIND ENERGY GENERATION IN NIGERIA

PROSPECTS OF WIND ENERGY GENERATION IN NIGERIA BY Chinedu J.E ABSTRACT About 90% of the Nigerian economy is dependent on crude oil. Expectedly, most of her generating plants are thermal power stations which are presently operating below installed capacity. This paper therefore looks at the prospects of wind energy in Nigeria. The wind speed data collected from some towns in Nigeria indicates that the country has good sites for the installation of wind energy conversion systems. The paper recommends the incorporation of wind energy in the renewable energy resources development programme of a developing economy like Nigeria. This would be a way of boosting her energy needs, as well as accelerating the sluggish nature of the nation’s rural electrification programmes. TABLE OF CONTENT ABSTRACT CHAPTER ONE INTRODUCTION BACKGROUND OF THE STUDY CHAPTER TWO 2.0 LITERATURE REVIEW 2.1 CONVENTIONAL ENERGY GENERATION IN NIGERIA 2.3 PERFORMANCE OF CONVENTIONAL ENERGY IN NIGERIA 2.4 MERITS AND DEMERITS OF CONVENTIONAL ENERGY GENERATION 2.5 Wind Power in Nigeria 2.6 Wind Power utilization today 2.7 The future of wind energy system CHAPTER THREE 3.0 WIND ENERGY DEVELOPMENT AND POTENTIALS IN NIGERIA POWER IN THE WIND WIND ENERGY POTENTIALS IN NIGERIA 3.2 METHOD 3.3 RESULTS CHAPTER FOUR 4.0 DISCUSSION OF RESULTS CONCLUSION AND RECOMMENDATION MERITS OF WIND POWER REFERENCES CHAPTER ONE 1.0 INTRODUCTION For the past ten years, the Federal government of Nigeria has embarked on aggressive rural electrification projects across the country. This laudable project is aimed at providing electricity to the rural dwellers where about 64% of the entire populations live. By this programme also, the Federal government hopes to minimize, if not curb the rural –urban migration—thereby forcing young school leavers and graduates to remain in the village self-employed rather than moving to the urban areas seeking white-collar jobs [1]. Often, however, the pace of rural electrification is far slower than rural people and the Federal government of Nigeria would like. Rural electrification is difficult because it is capital intensive and has unfavourable short-term economics. As is normally the case, with large central Power plants and grid-extension programs, rural electrification programs can easily fall victim to construction difficulties, routing impediments, competition from urban/industrial power demands, and a lack of implementation flexibility [2]. This conventional system of using large centrally located power plants and grid extension for rural electrification is currently being challenged by the advent of smaller, modular technologies such as wind power, micro-hydro and photovoltaics. This paper looks at the conventional energy generation as well as the wind energy potential in Nigeria. It highlights the importance of wind energy as a way of accelerating the sluggish nature of the Federal government of Nigeria rural electrification programmes. Relevant conclusions are made using available wind speed data collected at the various sites in Nigeria. 1.1 BACKGROUND OF THE STUDY Energy major impact on every aspect of our socio-economic life. It plays a vital role in the economic, social and political development of our nation [1]. Despite the abundance of energy resources in Nigeria, the country is still in short supply of electrical power. Only about 40% of the nation’s over 140 million has access to grid electricity [2]. Even the electricity supply to the consumers that are connected to the grid is erratic. There is therefore the need to harness renewable energy potential (such as wind, solar e.t.c) for reliable power supply in this country. Also the concern about global warming and continued apprehensions about nuclear power around the world should drive us into strong demand for wind generation. Wind turbine converts wind energy into electrical energy, which is fed into electricity supply system. The main advantages of electricity generation from renewable energy sources, such as wind, are the absence of harmful emissions, very clean and almost infinite availability of wind that is converted into electricity [3]. Wind generation has been described to be one of the mature and cost effective resources among different renewable energy technologies [4].Wind is a natural phenomenon related to the movement of air masses caused primarily by the differential solar heating of the earth's surface [5]. Wind is a classical example of a stochastic variable; due to this stochastic nature, wind energy cannot be controlled, but can be managed. This is because wind power is available only when the wind speed is above a certain threshold [6]. This paper therefore describes the wind energy potential in Nigeria and the conditions to be met before the wind generator can be connected to the existing grid and how it can be connected. The effect the new generation source might have on the existing power network will also be discussed. CHAPTER TWO 2.0 LITERATURE REVIEW The various wind generator projects in Nigeria were neglected in the last decade due to increasing popularity and low price of crude oil. Inrecent times the high price of Petroleum products lead to attempt at restructuring these windmills [5, 6]. However, difficulties in obtaining spare parts for models which were no longer being manufactured hindered the restoration. Also, some other factors that led to the failure of past wind generators are the assessment of wind energy potentials, feasibility studies on wind energy utilization , inadequate wind data base used as the bases for designing and building different prototypes that need be considered in reducing locally manufactured windmills. 2.1 CONVENTIONAL ENERGY GENERATION IN NIGERIA The bulk of the supply for electrical energy in the country has been from the National Electric Power Authority (NEPA). It expands annually in order to meet the ever increasing demand [3]. Presently, that task is being performed by the Power Holding Company of Nigeria, PHCN. Energy production and consumption in Nigeria has been on the increase. 2.3 PERFORMANCE OF CONVENTIONAL ENERGY IN NIGERIA At present, the installed and available electrical capacity in the Nigerian generating stations are shown in Table 1. It shows that despite a total grid capacity of 5924.7 MW, only 4586 MW were available. Thus 22% of the installed capacity was unavailable. This may be due to operational inadequacies and inability of units to operate at full capacities of the generating stations and their respective percentage contributions to the total energy products. Table 1: Generating plants—Grid Stations Key: + = Operational inactive Site Type Installed capacity [MW] Available capacity [MW] Number of units Afam Thermal 700 488 18 Delta Thermal 812 540 20 Egbin Thermal 1320 1100 6 Ijora Thermal 66.7 40 3 Sapele Thermal 1020 790 10 Jebba Hydro 540 450 6 Kainji Hydro 760 560 12 Shiroro Hydro 600 600 6 + Orji River Thermal 60 - 4 Others Diesel 46 18 - 2.4 MERITS AND DEMERITS OF CONVENTIONAL ENERGY GENERATION The use of conventional methods in electrical power generation has a number of advantages: 1 Hydro plants have lower operating and maintenance costs since no fuel and steam generators are needed. 2 Hydro plants are quicker to start up on load and are also quicker to shut down for maintenance. 3 Hydro plants are less prone to fire outbreak because of the absence of fuel. 4 Thermal power stations which are built on much smaller areas of land than hydro stations have fewer resettlement and compensation problems 5 Thermal stations have lower installation costs. 6 Installation can more easily be brought closer to a land centre for thermal plants. 7 The use of nuclear fuel does not require combustion air, avoiding thermal stack losses and related problems. The demerits of conventional energy generation are: 1 Hydro plants depend for sustained operation on in-flow of water into the storage and this in-flow can be affected up stream by drought and outside the borders of this nation, by political or other considerations. 2 The pollution arising in the case of thermal stations from combustion of fuel is not environment-friendly due to the fact that sulphur oxides, heavy metals, radio-active elements, hydro carbons and large quantities of cabon dioxide are emitted which leads to acid rain. 3 Fossil and nuclear fuels are finite and non-renewable energy sources [4]. 4 Burned nuclear fuel is radioactive, it requires remote handling and special processing and disposal of toxic waste. 5 Special system designs are required to prevent radioactivity release during normal operation or due to accidents. 6 Major portions of a nuclear plant are radioactive during and after operation, requiring special precautions and advanced technology for maintenance of much of the plant. 2.5 Wind Power in Nigeria Nigeria is blessed with abundant fossil fuel (oil and gas) and the Government investment in power generation had been mainly restricted to thermal coal plants, gas plants and hydro power stations. Adegoke and Anjorin (1996) investigated the prospects of wind energy utilization in Nigeria by analyzing available wind data for Akure, Bauchi and Port Harcourt and observed that the average wind speed measured at 10metres height above the ground for Bauchi is 4.78m/s, Port Harcourt is 2.56m/s and that for Akure is 0.76m/s. It was concluded that Bauchi favours the installation of wind turbines more than Port Harcourt and Akure and that the variation of annual mean wind speed is much lower for Port Harcourt than it is for Bauchi implying that wind turbines installed in Port Harcourt would function more regularly over several years. Wind speeds of not less than 2.22m/s have been found to be favourable for uses of windmills in northern Nigeria although this may strictly apply to the type of windmill tested. It has also been reported that most windmills would not start at wind speeds less than 3m/s (Ejieji, 2006). The National Energy Commission of Nigeria (NECN) is presently leading Research and Development (R&D) efforts in developing indigenous technology in wind energy conversion systems. 2.6 Wind Power utilization today The expected global shortage of oil and coal after World War II did not happen. Instead the prices of oil fell in the 1960’s. Energy consumption was increasing drastically as was the general growth and wealth in the industrialized countries. It therefore took a serious energy crisis before wind power once again was put back on the agenda. This turn around came in October 1973, when Egyptian troops crossed the Suez Canal entering Sinai, which Israel had occupied during the 6-day war in 1967. A war in the Middle East had started and this time oil was used as a weapon in the conflict. Throughout the 1950’s and 1960’s Organization of Petroleum Exporting Countries (OPEC) had gradually gained more and more control of oil and it subsequently decided to raise oil prices and introduced an oil embargo on countries supporting Israel. The resulting supply problems and rising prices not only caused downward market conditions in the Western world but also proved just how vulnerable and dependent these countries had become on the import of oil. Wind power was therefore soon back to reckoning. 2.7 The future of wind energy system In the years to come, the prime resource for generation of wind power will not be wind but windy sites. With only limited sites suitable for wind power generation available, it makes better sense to develop technologies, which will increase the efficiency of wind electric generators. The developments in turbine technology coupled with optimization techniques will lead to higher energy densities. Also it is expected that in future the power quality issues in grid interfacing wind electric generators will be addressed and power quality devices will be inbuilt into the turbines. The global wind energy installed capacity has increased exponentially over a 25-year period, and in the process the cost of energy (COE) from wind power plants has been reduced by an order of magnitude. Wind energy installations in the United States have grown during the past decade from about 1800 MW in 1990 to more than 6,000 MW at the end of 2003(Musial et. al, 2004). Offshore wind turbines have a number of advantages over onshore ones. The size of onshore turbines is constrained by capacity limitations of the available transportation and erection equipment. Transportation and erection problems are mitigated offshore where the size and lifting capacities of marine shipping and handling equipment still exceed the installation requirements for multi-megawatt wind turbines. The visual appearance of massive turbines in populated areas may be undesirable. At a sufficient distance from the coast, visual intrusion is minimized and wind turbines can be larger, thus increasing the overall installed capacity per unit area. Similarly, less attention needs to be devoted to reduce turbine noise emissions offshore, which adds significant costs to onshore wind turbines. Also, the wind tends to blow faster and more uniformly at sea than on land. A higher, steadier wind means less wear on the turbine components and more electricity generated per square meter of swept rotor area can be integrated to the national grid. Onshore turbines are often located in remote areas, where the electricity must be transmitted by relatively long power lines to densely populated regions, but offshore turbines can be located close to high-value urban load centers, simplifying transmission issues. On the negative side of offshore development, investment costs are higher and accessibility is more difficult, resulting in higher capital and maintenance costs. Also, environmental conditions at sea are more severe: more corrosion ice. And obviously, offshore construction is more complicated. Despite the difficulties of offshore development, it holds great promise for expanding wind generation capacity. CHAPTER THREE 3.0 WIND ENERGY DEVELOPMENT AND POTENTIALS IN NIGERIA POWER IN THE WIND The theoretical power in the wind is given by [7]-[14] ρπ ( (1) where Pae is the aerodynamic power extracted from the airflow [Watt], ρ is the air density [typically 1.225Kg/m3] Cp is the power coefficient which is the fraction of power in the wind captured by a wind turbine, which depends on the pitch angle θpitch [degree] and on the tip speed ratio, is given by λ = (2) i.e it is the ratio between the blade tip speed *R and the equivalent wind speed Veq [m/s2], R is the rotor radius; Cp is equal to 0.59 which means, the 59% of wind power is the maximum power that a wind turbine can utilize. Equation (1) shows that the power which a particular wind turbine can extract from wind is a cubic function of the wind speed. Once the aerodynamic power is determined, the aerodynamic torque can be calculated directly according to = = ρπ ( (3) The mechanical input can be chosen as either the mechanical power or the mechanical torque, and then the other quantity can be calculated using equation 3 [15]. WIND ENERGY POTENTIALS IN NIGERIA The technologies for harnessing wind energy have, over the years, been tried in the northern parts of the country, mainly for water pumping from open wells in many secondary schools of old Sokoto and Kano States as well as in Katsina, Bauchi and Plateau States. Other areas of “potential application” of wind energy conversion systems in Nigeria are in Green electricity (which is the type of electricity produced from renewable source that is environmentally friendly and non-polluting) production for the rural community and for integration into the national grid system. In 1998, a 5-kW wind electricity conversion system for village electrification has been installed at Sayyan Gidan Gada, in Sokoto State [16]. According to the report of Lahmeyer (International) Consultants [17], wind energy reserve in Nigeria at 10m (or 40m) height based on data analyzed for ten wind stations cutting across North West, North East, North Central, South East and South West geopolitical zones shows that some sites have wind regime between 1.0 and5.1m/s (1.0 and 6.3m/s) depending on the particular stations, and still confirms that Nigeria falls into the moderate wind regime. Wind energy resources mapping for ten (10) sites in Nigeria including Sokoto collected from on ground measurement carried out between May 2004 and May 2005 also by Lahmeyer International. It can be seen from the table that the sites are potential wind farm areas. This is because most wind turbines start generating electricity at wind speeds of around 3-4 meters per second (m/s) [18]. It was reported that offshore areas from Lagos State through Ondo, Delta, Rivers, Bayelsa to AkwaIbom states also have potentials for harvesting strong wind energy throughout the year. Detailed wind speed measurements and data carried out in Nigeria in some hilly and coastal areas have shown an excellent wind potential for implementation of wind farms in those areas. Table II below shows the wind energy density estimate at 25m height. It can also be seen from the table that Sokoto and Jos have the annual wind energy from wind turbine (kWh) of 97,035.94 and 94,559.98 respectively [19]. These figures are also in agreement with Ojosu and Salawu survey of wind energy potentials in Nigeria [20]. A number of authors [19] - [23] recommended base on the wind speeds that these potential wind farm areas should be connected to the grid (at Distribution level). The Director General of Energy commission of Nigeria in a Paper presented at International Association for Energy Economics Third quarter 2009 [21] still lamented that these renewable Energy resources most especially wind have not been integrated to the Nigeria grid. Table I. showing ranking of the wind speed at various measurement stations [17]. Site ID Site Name Measured mean wind speed at 30m Height (m/s) Sok 01 Sokoto/Badaga 5.4 Jos 01 Jos Airport/ Kassa 5.2 Gem 01 Gembu/Mambila plateau 5.0 Pan 01 South part of Jos plateau/Pankshin Hotel 5.0 Kan 01 Kano/ Funtua 4.9 Mai 01 Maiduguri/mainok 4.7 Lag 01 Lagos/ Lekki Beach 4.7 Enu 01 Enugu/Nineth mile corner 4.6 Gum 01 Gumel/ Garki 4.1 Ibi 01 Ibi metrological station 3.6 3.2 METHOD In an attempt to discover wind energy potential in the country, several sites (Enugu, Jos, Ikeja, Abuja, Warri, Sokoto and Calabar) which differ in natural conditions and having different wind characteristics were selected for this study. Figures 1-7 show the wind speed graphs for various stations from 2000 to 2003. 3.3 RESULTS From the graphs, it was discovered that the annual wind mean speed at a height of 10m above the ground ranges between 2.3m/s to 3.4m/s for sites along the costal areas and 3.0m/s to 3.9m/s for high land areas and semi-arid regions. The analysis carried out on the data shows that the monthly average wind power can be as high as 50.1W/m 2. Small wind energy conversion systems for pumping water, irrigation and small agricultural industries are recommended for small communities living in isolated areas around the selected sites. It was also discovered that the wind turbine can generate up to 97MWh per year in Sokoto, a site in a high wind speed regions [7]. Therefore, using wind energy conversion systems for electric power generation and supply in Nigeria—especially around the Sokoto axis will be cost effective. Similarly, after analysis of wind potential of a town near Jos, it was discovered that the maximum power intensity which could be extracted from the wind inthe area was found to be 14.23W/m2 out of the estimated available wind power intensity of 24.00W/m2 .The amount of energy density available in the wind has also been estimated to be 1126.28KWh/year. These results suggest that Heipany, a town in Jos, is an ideal location for construction of wind mills. CHAPTER FOUR 4.0 DISCUSSION OF RESULTS 1. The use of wind power for the supply of electricity broadens the energy base and reduces environmental pollution. It is particularly practical if it can be made economically competitive with conventional energy sources [8]. 2. The use of wind energy will be suitable for rural farming companies that require lighting and some limited supply of electricity which will be costly to get due to the location of farms [9]. 3. Several researchers [10, 11] have shown that in areas with annual mean windspeeds of 3.5m/s-4.0m/s or greater, wind power systems can usually deliver electricityor pump water at costs lower than photovoltaics, diesels, or grid –extension. 4. Wind energy conversion systems (WECs) provide power source for unattended remote sensing stations, such as weather stations which periodically transmits metrological data. 5. In remote areas, where purchased electricity is simply unavailable, wind energy may well be the only alternative. 6. WECs enjoy flexibilities in implementation, lower life-cycle energy cost, reduced dependence on fuel supplies and the possibility of local production and support. 4.1. CONCLUSION AND RECOMMENDATION MERITS OF WIND POWER By using metrological data collected from some selected weather stations in Nigeria, analysis of such data shows that wind power prospects in Nigeria is high. From the analysis also, it was clearly seen that costal and hilly areas are excellent sites for wind power development. Therefore, using WECs for electric power generation and supply in Nigeria—especially around Sokoto axis with mean wind speed of about 3.78m/s, will be cost effective. Considering the prospect of wind energy in a developing economy like Nigeria, the following recommendations are made: 1. Excellent sites such as Jos and Sokoto should have a wind power plant for the generation of electricity which should be integrated with the existing national grid. 2. Wind energy resources should be included in the renewable energy resources development programme of Nigeria. 3. The Nation’s energy centres should be encouraged through funding in order to stimulate research efforts on WECs and manufacture. 4. Issues relating to energy should be handled by experts. 5. The government should set up independent policy makers on renewable energy, whose tasks will be to monitor the Nation’s energy centres as well as to encourage the Energy Commission of Nigeria, ECN to embark on intensive human resource training on areas of need. REFERENCES [1] Fagbenle,R.L.: “Prospects and problems of solarizing transport technology”. Nigerian Journal of Renewable Energy, Vol. 2, No.1, 1991, pp. 79-84. [2] Bergey,M.L.S.: “Small wind Turbines for rural energy supply in Developing Countries”, Journal of Renewable Energy for Agriculture and Health, 1999, pp. 1-6. [3] Okoro, O.I. and Madueme, T.C.: “Solar energy investments in a developing economy”,Renewable Energy 29, 2004, pp. 1599-1610. [4] Davidson,I.E. and Oni, J.O.: “Energy conversion strategies and alternative sources for Africa”, Nigerian Journal of Renewable Energy, Vol. 2, No.1, 1991, pp. 85-90. [5] Ojosu,J.O. and Salawu, R. 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