Nuclear power now carries 70% of Ukraine’s electricity—up from more than half before the war—not because Kyiv built new reactors, but because Russia destroyed almost everything else, Energoatom told Reuters.
Ukraine’s reactors still work. The high-voltage substations increasingly do not.
The vulnerability has shifted with it. Ukraine’s reactors still work. The high-voltage substations that move their power onto the grid increasingly do not. In January, Ukraine warned the OSCE that Russia was preparing a coordinated strike campaign specifically against that infrastructure, damage that can force reactors into emergency protocols designed for accidents, not warfare.
How Ukraine got here
Reuters reported that, before 2022, thermal generation accounted for up to 35% of Ukrainian demand. Strikes have reduced it to a fraction. At one point this year, an industry source said reactors covered up to 80% of consumption.
Ukraine started the war with four operational nuclear plants and 15 reactor units.
“Nuclear generation is carrying the system’s main baseload,” said Mykhailo Babiichuk, general manager for security and sustainable development at Kyiv-based think tank DiXi Group.
Ukraine started the war with four operational nuclear plants and 15 reactor units. Within months, the Zaporizhzhia Nuclear Power Plant—the biggest in Europe—was under Russian occupation and shut down. The plant remains in cold shutdown today, cut off from the Ukrainian grid. That single loss removed 43% of Ukraine’s total installed nuclear capacity.
Russia has struck every major thermal and hydropower plant in the country.
What is striking is what happened next. Ukraine lost its largest reactor complex. And its share of nuclear in the national grid still went up.
That is because the rest collapsed faster.
In 2024 alone, 10 gigawatts of generating capacity—more than half of peak Ukrainian consumption—was damaged or destroyed, DiXi Group told Reuters. Russia has struck every major thermal and hydropower plant in the country. Many still stand. Not all can still produce power.
The substations are the real target now
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Ukrenergo has reported that strikes on 750 kV and 330 kV substations force operators to throttle reactor output—not because the reactors are damaged, but because the grid cannot absorb what they produce. Russian attacks have already affected the ability of two plants—South Ukraine and Khmelnytskyi—to operate at full capacity, Reuters wrote.
“The higher the share of nuclear generation in meeting demand, the higher the price of any disruption in the nuclear-grid circuit for the entire state,” Babiichuk told Reuters.
Building a strategic reserve of 50–100 mobile substation units is now a priority ahead of next winter.
Ukraine’s own energy minister is treating it that way. First Deputy Prime Minister and Energy Minister Denys Shmyhal said this week that building a strategic reserve of 50–100 mobile substation units is now a priority ahead of next winter.
A thermal plant hit takes a region offline for weeks. A critical substation feeding a nuclear plant, hit the wrong way, can take a country offline.
What the war has actually built
One gain: Reuters reported that since 2022, Ukraine has commissioned a spent nuclear fuel storage facility, ending its dependence on Russia for that service. Energoatom has also announced plans for ten small modular reactors by 2050.
Neither changes the current arithmetic. A grid Russia cannot destroy at the source hangs on substations Russia has already shown it can reach.
