In wikipedia it says that Eskom is registered as a public company wholly owned by the government.

And it got me thinking, now since Eskom is owned by the government, isn't that company used by TSHWANE municipality to supply people with electricity then?

Even though it is called a public utility, it turns out that ESKOM is not used by the government or at least by the TSWHANE part of the government, to get power to the people.

The municipality of Tshwane is making lot of profit through electricity. The amount that ESKOM is charging for a unit is unreasonable; Tshwane is charging extra because they want to benefit. ESKOM is charging 25 cents per unit whereas Tshwane is charging 70 cents. - Source "electricity of tshwane"