It's funny you dismiss hydro so quickly. There are many potential large hydro sites with very low levelized cost of energy in Sub-Saharan Africa. Many of the governments in Africa think hydro is a great option, and that's where a lot of development is currently going. To quote from an International Energy Agency report in 2016 (Boosting the Power Sector in Sub-Saharan Africa: China's Involvement):
"Renewable sources account for 56% of total capacity added by Chinese projects between 2010 and 2020, including 49% from hydropower."
If you take a look at Map 2 in that report, hydropower projects dominate in central and east Africa. Figure 1 shows that Chinese contractors account for 30% of all new capacity additions in sub-Saharan Africa, although elsewhere in the report you read that Chinese contractors are essentially the only ones building large hydro and coal.
So regardless if it's a great option (and I agree, environmental and social risks of large hydro can be very high and need to be addressed), it's happening, and it's happening because it's cheap (enough to be profitable for a developer with a 30 year Built-Operate-Transfer agreement).