Nigeria’s poor electric power supply has grossly affected the economy, slowing down countrywide development. The ever-increasing demand for power supply coupled with its limited availability has been an impediment to her socioeconomic development. The failure to generate and distribute sufficient power has been well documented alongside the inability to realise a lasting solution that wholly addresses the problem. This thesis approached realising a solution by firstly presenting an overview of Nigeria’s energy sector in order to identify the barriers to renewable energy uptake. Some of which were high capital costs, lack of access to finance, technical ineptitude, technology paucity, limited public awareness and the lack of government policies or poor policy framework. Thereafter, the analyses of data from the multi-sectors (commercial, industrial, residential and education) realised through interviews and surveys, elicited energy cost savings, energy security and autonomy, improved quality of life, and environmental concern as the motivation for encouraging renewable energy and particularly solar-photovoltaic (PV) uptake. Building on these insights, this body of research presented a case for multi-sectoral adoption of solar-PV as an electricity supply option considering grid power supply unreliability. The technical, economic, environmental and social viability of implementing solar-PV technology were studied by working with country-specific data obtained from surveying the commercial, industrial and residential sectors in Nigeria. These sectors were surveyed to determine the extent of the countrywide power supply unreliability as well as understand the level of public awareness and the societal acceptance of solar-PV as a power generating technology. Cases studied, evidenced the socioeconomic impact of unreliable power supply in Nigeria and a solution to the power supply shortfall is also presented. Numerical simulation and quantitative analysis methods were employed in analysing data and assessing the results. Retrofits to existing petrol/diesel generator systems for the commercial and industrial sectors (C&I) delivered benefits of lower CO2 emissions, improved systems reliability and reduced grid power dependence at lower lifetime costs than existing power systems. The results from the data analyses suggest that partial to total grid defection solutions that integrate solar-PV technology could be implemented across sectors countrywide, towards improved electrification. Results present a basis for a shift from the power sector electrifying all other sectors to the multi-sectors contributing to the power sector’s effort in extending, increasing and improving countrywide electrification. This can be achieved by incentivising the uptake of hybrid photovoltaic-centric power systems (solutions deployed directly where they are needed) as well as taking advantage of the excess power generation from such systems. These solutions would need to be supported by policy and an implementable regulatory framework. This would bring about a measurable improvement in the socioeconomic status of the citizenry and the broader nation.