I posted some studies done on upgrading the existing Hydro in WC in the hydro power thread.
Costs are quite reasonable, surprising it hasn't been done already to be honest.
Linky -
https://mybroadband.co.za/forum/threads/hydro-electricity.1163260/post-28423626
Fairly obvious from the article, that this ISN'T what they're talking about though -
"What we will be looking at and where they may well play a role is when we move towards a more advanced load management control which means we will be able to do interventions and installations of a particular smart device to pass over control to the home owner to allow them to manage their electricity demand more efficiently and more smartly. So that is being assessed at present and should it be viable subject to a feasibility study, we're looking at the mechanics of how that would be rolled out."
Reading the not so subtext, what they're talking about is (mandated) demand side load reduction.
i.e. we don't have enough power, we're going to shut off your Geyser.
This would be best done with financial incentive really, i.e. Time of Use billing. The meter rollout for that is going nowhere fast though.