Last winter, Russia deliberately targeted Ukraine’s electricity and heating infrastructure to leave Ukrainians in the cold and dark. Large parts of cities like Dnipro, Kharkiv, Zaporizhzhia and Kyiv were left without heating from early January until spring, while the whole country experienced power cuts lasting up to several days.

With temperatures in Kyiv reaching around 25C this week, the end of the heating season has brought some relief to grid workers.

People need less power and heat, while the grid can rely more on solar generation. But that doesn't mean there is much time to rest. The power grid is such a vast, dynamic system that it takes time to repair and restore properly.

And Russian attacks on the energy infrastructure haven't stopped fully.

During the latest heavy shelling of Kyiv on 2 June, two engineers from DTEK, the largest private investor in the energy sector in Ukraine, were injured at a production site.

Ukraine's roughest winter

More than 700 rockets targeted Ukraine's energy infrastructure during the most vulnerable winter months. Not a single thermal power plant in the country was left untouched, and Russia targeted the same stations several times.

According to Ihor (name changed for security reasons), the head of one of the Ukrainian power plants, last winter was probably the hardest he had experienced in his professional life.

The frosts were minus 25 degrees. Due to shelling, the power plant was left without a roof, exposing the engine and boiler rooms to sub-zero temperatures.

“The equipment was literally freezing before our eyes after the shells were landing. And we had to act very quickly to save it,” he said.

Various measures were taken to get through the winter. The entire workforce, including management and operational staff, was organised into shifts to work on the equipment around the clock. The workers had to heat it up by lighting gas and wood-burning stoves.

During air raid alerts, they rushed to the bomb shelters, except for the operational staff, who risked their lives to keep the power running.

“I believe that the men at the control panels at all the stations are heroes of their profession,” Ihor proudly told TEC.

Damaged network

Maksym Yevhun, head of the unit responsible for repairing distribution substations in Kyiv, also had a hard time in winter. He and his team of three were working to increase the electricity supply capacity. But in the cold, their equipment broke down, and generators froze. They had to work with emergency services to defrost the generators and get them running again.

Just like Ihor's team at the power plant, they were working around the clock, too. There was a lot of shelling during nighttime operations. They would take cover, but when the substation was hit, they would go straight to the point of impact and work on repairs.

One of the most difficult aspects of Maksym's team's work was dealing with the public during the power cuts. The frustration grew in Kyiv during the toughest weeks, and so while some residents offered tea and biscuits to the workers, others snapped at them. “Both are understandable,” Maksym said.

He hopes Ukrainians have learned to be careful with electricity use in a crisis. When residents who have been without power switch on a large number of appliances as soon as it comes back on, the voltage becomes overloaded and knocks out the generators powering the substations, he explained.

Maksym and his team are currently restoring electrical equipment at substations and preparing them for what might be another rough winter.