Solar energy harvesting on building's rooftops: A case of a Nigeria cosmopolitan city.

• The rooftop PV electricity potential has been evaluated for the city of Ibadan. • Optimum fixed tilt angle for rooftop PV deployment in the city of Ibadan is 11°. • The total roof area of the city was estimated as 49,540,000 m2 (i.e. 49.54 km2). • The available roof area for rooftop PV deployment was evaluated as 7,542,500 m2. • The annual solar energy harvestable on rooftop was estimated to be 6.6714 TW h/year. In this paper, the possibility of meeting the growing electrical energy demands of the city of Ibadan (one of the Nigeria cosmopolitan city) using the rooftop solar PV systems is investigated with the aim of determining the available rooftop for possible PV deployment. First, the optimal tilt angle as well as solar irradiation on tilted surfaces are determined for the city, Thereafter, the available roof area for possible solar PV- rooftops placement are analysed using reduction factor technique with the aid of ArcGIS, Google earth Imagery and population sampling techniques. Some of the key results reveal that the total roof area for the city of Ibadan is about 49.54 sq km while the available roof area for rooftop PV deployment is about 7.54 sq km with a maximum installation capacity of 1734.8 MWp, at an optimum fixed tilt of 11°. This could generate PV electricity of about 6.67 TW h per annum. This paper is important as it could serve as first-hand scientific information for government agencies, NGOs, investors, researchers and policy makers at maximizing the potential of solar PV rooftop potentials in Nigeria. [ABSTRACT FROM AUTHOR]