The full powerplant is not abandoned, only these parts are not used anymore, but they don't demolish them because it's a protected monument.
Originally it was a coal powerplant, in the 1970s they switched to gas, adn these control rooms not used since that. They also use it for district heating nowadays.
Hungarian wiki is also very detailed about it: https://hu.m.wikipedia.org/wiki/Kelenf%C3%B6ldi_Er%C5%91m%C5%B1
You can try to read it with an online translator: https://hu-m-wikipedia-org.translate.goog/wiki/Kelenf%C3%B6ldi_Er%C5%91m%C5%B1?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=hu&_x_tr_pto=wapp