Skyscrapers are without electricity up to 12 hours a day. Neighborhoods are filled with the roar of gas generators installed by cafes and restaurants. And at night, streets are plunged into darkness for lack of lighting.

That is the new reality in Ukraine, where the approach of summer has offered no respite for the country’s power grid, but has instead brought a return to the kind of energy crisis experienced during its first winter at war, a year and a half ago.

In recent months, Russian missile and drone attacks on Ukraine’s power plants and substations have left the country’s energy infrastructure severely hobbled. To make matters worse, two nuclear power plant units are scheduled for repairs this week, and summer temperatures are expected to prompt people to turn on their air-conditioners.

As a result, the Ukrainian authorities have ordered nationwide rolling blackouts for this week, a more aggressive measure than the regional and irregular power cuts that parts of the country had been experiencing earlier this spring.

Volodymyr Kudrytskyi, the head of Ukraine’s national electricity operator, Ukrenergo, said on Sunday that the power shortage facing the country this week would be “in a rather serious volume.”

Ukrenergo said emergency blackouts were applied in seven of Ukraine’s 24 regions on Tuesday.

While power shortages in the summer can leave people uncomfortably hot in dark apartments, they pose a more deadly risk in the winter.