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A KEY PERFORMANCE INDEX APPROACH FOR ASSESSMENT OF GLOBAL SOLAR RADIATION IN NIGERIA
Authors: Ganiyu Adedayo Ajenikoko1, Abdul Ganiyu Adebayo Jumah2

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Global solar radiation is the sum of direct, diffuse and reflected solar radiation. Direct solar radiation passes directly through the atmosphere to the earth surface. Diffuse solar radiation is scattered in the atmosphere and deflected solar radiation reaches a surface and is reflected to adjacent surface. This paper presents a key performance approach for assessment of global solar radiation in Nigeria. The mathematical modeling of the system Cost Of Energy (COE) in #/kWh was formulated subject to the reliability condition for the computation of the energy contributions of the PV source, wind source and the grid source. The performance characteristics of the system are characterized in terms of its reliability in providing a cost- effective energy solution for satisfying the energy demand within the entire period. The results of the work shows that the percentage PV contributions of Abuja, Benin City Katsina, Lagos, Nsukka and Yola are 32.63%, 34.58%, 55.84%, 55.32%, 39.12% and 42.02% respectively, thus ranking Kastina as the highest and Abuja as the least due to the thick population of Kastina and the percentage variation of the renewable energy contribution in the Norther part of the country. The percentage energy contribution of wind for Abuja, Benin city, Kastina, Lagos, Nsukka and Yola are 70.69%, 66.71%, 38.84%, 22.08%, 34.92% and 22.83% respectively while that of grid are 8.88%, 10.71%, 17.32%, 34.68%, 37.96% and 48.175 respectively thus ranking Abuja as the city with the highest percentage wind energy contribution of 70.69% and Lagos as the city with the least percentage wind energy contribution of 22.01%. In the same vein, Yola emerged as the city with the highest percentage grid energy contribution of 48.178% with Abuja having the least percentage grid energy contribution of 8.88%. This is because the contribution of wind energy is largely limited by the sharp decrease in the annual average wind speed in the Southern part of the country. The percentage of the wind energy conversion system varies from about 22.18% in Yola to 70.69% in Abuja because a large fraction of solar energy is required to compensate for the available grid electricity supplied. Abuja and Yola recorded the highest and least energy throughput of 8.10kWh/N and 5.22kWh/N respectively while the energy throughput, for Benni city, Kastina, Lagos and Nsukka are 7.47kWh/N, 6.62kWh/N, 5.74kWh/N and 5.58kWh/N respectively. The highest and least costs of 0.168 #/kWh and 0.111 #/kWh were recorded by Yola and Abuja because the Northern part of the country has significant improvement in the overall system cost of energy supplied. The implementation of the stand-alone PV- wind energy system is a more viable option. This will reduce the larger land area needed for the stand-alone hybrid renewable energy system.
Keywords:: Key Performance Index (KPI), Solar Radiation, Photovoltaic, Cost of Energy, Loss of Supply Probability, Loss of Power Supply Probability, Energy Throughput, Energy Contribution.