While there is a very strong argument for providing cheap, subsidized power for the poorest in society, this should be done in a way that limits subsidies to the really deserving and the system as a whole needs to be able to charge tariffs that on average cover all costs. If this doesn’t happen then all manner of bad things will follow. As you might guess prices have been set too low by African governments. These subsidies have also been made too widely available, benefitting the elite and middle classes more than the poor (who, not having good access to the grid in the first place, don’t have ready access to these subsidies).
Fixed-rate, long-term (contract) plans provide stability in electricity rates. If market energy costs suddenly trend upward where you live, you can rest assured that you won’t have to pay more out of pocket. However, if you want to switch to a different, lower-cost plan before the end of the contract term, you’ll likely have to pay a cancellation or early termination fee.