The economic implications of using solely wind energy or solar photovoltaic (PV) system for electric power generation in Nigeria is considered in this work. Twelve states from the six geopolitical zones of Nigeria were used as case studies for wind energy utilization while 6 states were used for solar energy usage. Wind speed and solar radiation data for the state capitals were used for the analysis. The net present value (NPV) and the levelized cost of electricity (LCOE) for each state for a project lifespan of 20 years was estimated for each power system in the various states using discount rate equivalent to the prevailing interest rate (16%) in Nigeria and lower values. At 16% discount rate for wind energy system, only 4 states gave positive NPV while at 8% discount rate 9 states have positive NPVs. For the solar PV system, the NPVs are negative for all the 6 states at 16% discount rate while only one location with the highest average annual solar radiation of 6.4 kWh/m2 day gave positive NPV at 8% discount rate. The LCOE is smaller for wind energy systems in many of the locations considered. When energy is not discounted, the highest and the lowest LCOE for wind energy system are 0.1937 $/kWh and 0.0167 $/kWh respectively while the respective values for solar PV system are 0.0615 $/kWh and 0.0415 $/kWh. The LCOE when energy is discounted is higher and the average value obtained either system is higher than the price of electricity in Nigeria but lower than the electricity price in the UK and the USA. Thus for wind and solar PV systems to be more economically viable for electricity generation in many locations in Nigeria, the current installation costs should come down and or the price of electricity should go up.