Ukraine has begun putting parts of its electricity grid underground, betting that concrete and depth will do what air defence has not.

Zaporizhzhia is building underground structures at two transformer substations, the regional authorities said, and more than half of the region's key transformers are already covered by protective shells. Ivan Fedorov, head of the Zaporizhzhia regional military administration, said in late July that the work was “in the final stretch”.

The region sits on the front line of the looming Russian winter bombardment that is expected to target what remains of Ukraine generation capacity. Russia has spent three winters trying to take Ukraine's grid apart and freeze Ukraine into submission. A Shahed costs a fraction of the missile fired at it, and a transformer takes months to replace. Burying the asset changes that trade.

Ukrenergo, the state transmission operator, has been moving the same way at national level. It completed its first underground substation relocation earlier this year with a second under way, at a cost of tens of millions of dollars each, and estimates it needs about $100mn to shelter roughly 100 key ultra-high voltage 750kV substations as well as the less technically complicated regular substations - money it does not have. By the end of 2025 it had spent some $300mn putting concrete shields over more than half its transformers, with the rest due this summer.

The substations serving the thermal power stations have mostly been protected by Ukrenergo, the utility responsible for thermal and hydropower stations. The substations serving the nuclear power plants (NPPs) are controlled by Energoatom and have been left largely untouched. That is because money that was due to be invested in concrete bunkers to protect them was siphoned off by associates of Ukrainian President Volodymyr Zelenskiy in a $100mn kickback scheme, a corruption scandal that has rocked Zelenskiy’s administration. Now the government is racing to reinforce the power sector’s infrastructure as winter looms and the heating season is only a few months away.

“Moving substations underground can be one of the important elements of energy security and resilience in the future,” Ukrenergo chief executive Vitaliy Zaichenko has said. “But it will take years and millions of euros.” The company plans to approach the European Investment Bank, which put €86mn into anti-drone protection in 2024, once it has restructured $825mn of debt.

The tactic is spreading beyond Ukraine. Estonia moved to fortify its own grid with concrete shielding in March after a drone hit a power plant.