3.3.2. Solar Power Resources

Nigeria lies between latitudes 4◦ and 14◦ N (slightly north of the equator), and longitudes 2◦ and 15◦ E (slightly east of the prime meridian). The whole country falls within an area where sunshine is plentiful. Due to its location, the country's solar radiation is relatively well distributed, and the yearly daily mean varies from about 3.5 kWh/m2 in the coastal part to 7.0 kWh/m2 in the far northern part [64]. The solar irradiation details of the selected sites are again retrieved from the NASA POWER database (for a period of twenty-two years) [63] by specifying the coordinates of the selected zones for the planned installation of RE-based EV charging schemes. The changes in the monthly mean solar irradiation of the different locations are presented in Table 6. The annual average values of 6.24, 4.74, 4.93, 4.13, 5.90, and 5.49 kWh/m2/day were obtained for Sokoto, Ikeja, Enugu, Port-Harcourt, Maiduguri, and Minna, respectively. The corresponding minimum and maximum radiations of 5.25, 3.95, 3.91, 3.11, 5.14, and 4.36 kWh/m2/day at a clearness index of 0.64, 0.394, 0.381, 0.315, 0.491, and 0.419 and 7.15, 5.49, 5.74, 5.24, 6.7, and 6.26 kWh/m2/day at a clearness index of 0.678, 0.556, 0.58, 0.550, 0.661, and 0.611 were reported in various months. Moreover, the yearly mean air temperatures of 27.92, 25.92, 25.21, 25.59, 28.00, and 25.01 ◦C were reported for Sokoto, Ikeja, Enugu, Port-Harcourt, Maiduguri, and Minna for about 30 years [63] as depicted in Table 7.

**Table 6.** Solar radiation data of the case study sites for EVCS (kWh/m2/day) [40].



**Table 6.** *Cont.*

**Table 7.** Air temperature data of the case study sites for EVCS (degree celsius) [40].

