Temelin, nuclear power plan [1]. Pretty nice information center in a historical building with models, plant simulator and a small cinema. Although the most exciting part is visiting the actual power plant site - generators, accompanying infrastructure, going through radiation check point. Not sure if the site visit is publicly available.
Lipno, hydro plant [2]. Not as interesting information center as in Temelin, but the underground facility with turbines, generators and outlet tunnels makes you realize the huge mass of water in the dam and the amount of power the plant is able to generate.
The next item on my bucket list is pumped-storage in Dlouhe Strane [3], which looks like a hill with the peak cut off, having there a large pond instead.
Sources: [1] https://www.cez.cz/en/power-plants-and-environment/nuclear-p... [2] https://www.cez.cz/en/contacts/information-centers/lipno-inf... [3] https://www.cez.cz/en/contacts/information-centers/dlouhe-st...