On costs, solar energy is cheaper to harness compared to HEP. Also it is better and more efficient (eco-wise). The northern Nigeria is blessed with great solar energy and wind power but our government is not getting the best out of this.
To construct a dam, people will be displaced, lots of natural ecosystem altered. But solar panel can be just installed on just about any plain field with no obstruction from direct sunlight. People can also be encouraged to fit smaller solar panels in their homes (on roofs). This will drastically reduce our over reliance on HEP.
Wind farms can also be started where hundreds (or even thousands ) of wind turbines will be installed. HEP relies on water volume which is seasonal. There is always sun and wind, in both the wet and dry seasons.