The airstrike, carried out with ballistic missiles and cruise missiles fired by Russian strategic bombers based in the Arctic Circle,
was the fourth large-scale aerial assault targeting the power system since March 22.
Rescuers battled to put out fires at several energy facilities in the
western regions of Lviv and Ivano-Frankivsk, which border NATO members Poland and Romania, officials said.
After strikes on energy facilities in the central Dnipropetrovsk region, running water supplies were disrupted in President Volodymyr Zelenskyy's hometown of Kryvyi Rih, officials said.
Ukrainian air defenses brought down 21 of the 34 incoming missiles, the commander of the air force said in a statement.
None of the facilities hit was identified by name, a security measure intended to prevent Russia quickly assessing the impact of its strikes.
In the northeastern city of Kharkiv, which has been heavily bombed in recent weeks,
a missile struck a hospital holding 60 patients overnight, injuring a woman and damaging the building, nearby water pipes and power lines, the regional governor said.
Russia, which began its full-scale invasion of Ukraine in February 2022, denies targeting civilians but says the Ukrainian energy system is a legitimate military target.
Ukraine has lost 80% of its thermal power generation and 35% of its hydroelectric capacity during Russian attacks, officials say.
Though the core of the energy system comes from nuclear power, that lost capacity serves a balancing function in the grid and its loss could be a big problem when consumption rises later this year.
