TNB's latest TV ad is disingenuous. It's not that the cost of electricity has risen. It's that the cost of importing coal has risen.
They're airing the ads as if to warm people up to the idea of raising tariffs.
They should've instead put more resources into renewable energy but the people in charge are too sootbrained, as in every other institutions in the country.
I think that from TNB's point of view, cost of electricity has indeed increased. If I'm not mistaken, TNB buys energy from suppliers (the power stations and any overseas links), distributes and sells to consumers.
It's actually the government's fault, I think there was some discussion about non-tender, direct negotiation to award power plant contracts. IIRC this was brought up by Yeo Bee Yin in one of her social media posts back when she was Minister of Energy, Science and Technology.
I have checked again, and it's actually mix. TNB used to own all its own power plants, then starting in the 90s the govt started awarding power supply contracts to Independent Power Producers. Some familiar names are YTL Power, Malakoff.
It not sure how much of IPP's production share now, but it looks like large proportion of power comes from IPPs now.