Zaporizhzhia plant no longer connected to Ukraine grid

Ukraine has four nuclear power plants with a total of 15 units. They produce 50-60% of the electricity in the national grid, according to the state energy company Ukrenergo.

The plant in Zaporizhzhia is the largest not only in Ukraine, but also in the whole of Europe. It has six power units with a total capacity of 6,000 MW. And it generated almost half of the electricity produced by Ukraine's nuclear power plants before the Russian attack, according to Petro Kotin, head of Ukraine's state-owned nuclear power plant operator Energoatom.

Now it appears that the Kremlin intends to integrate the nuclear power plant into Russia's power grid. On Thursday, Nov. 3, Energoatom announced that Zaporizhzhia is currently running on emergency diesel generators after the last remaining power lines were cut by Russian shelling. The nuclear power plant could operate for 15 days on the available fuel, Energoatom said. Although the six reactors have already been shut down, the plant still needs an uninterrupted supply of electricity to ensure cooling. Otherwise, a nuclear disaster could occur.

The energy agency expects that Russia will try to connect the nuclear plant to the power grid in the Russian-occupied territories of Crimea and Donbas. Moscow said Thursday that Russia had merely protected the nuclear plant from Ukrainian fire.

'Technically complex' connection

Russian troops have been using it as a depot for weapons and military equipment, according to Energoatom's website. "The Russian military is shelling the nuclear power plant to destroy its infrastructure and disconnect it from Ukraine's energy system."

Since then, the nuclear power plant has been disconnected from Ukraine's power grid several times by Russian shelling. After those attacks, the plant's workers managed to reconnect Zaporizhzhya to the Ukrainian grid and ensure it would keep generating electricity for Ukraine.

"The nuclear power plant has not been running at full capacity since the occupation. Two, sometimes three units are in operation, with the third not running at full capacity. How much electricity the nuclear power plant generates for the Ukrainian grid is kept secret due to martial law," Mariia Tsaturian, who is responsible for communications and international cooperation at Ukrenergo, told DW.

"To safely disconnect the Zaporizhzhia nuclear power plant from the Ukrainian grid and safely connect it to the power grid of occupied Crimea, it would take a technically complex desynchronization and subsequent synchronization, disconnecting one line at a time," Tsaturian said, adding that the frequency in the grid of 50 Hertz would have to be maintained at all times to avoid problems or outages.

Difficult winter approaching

Now it looks like Russia is planning to take this difficult step — at the worst possible time for Ukraine. Winter is just around the corner and energy is urgently needed for heating.

"Ukraine urgently needs the Zaporizhzhia nuclear power plant or it will not be able to fulfill its electricity export obligations. The electricity produced is intended exclusively for securing the heating season," said Volodymyr Omelchenko, energy expert at the Kyiv Razumkov Research Center. The country needs the plant, says Olena Pavlenko, head of the DiXi Group analysis center, which monitors Ukraine's energy market, adding that electricity exports "support the energy sector and compensate companies for decreased electricity prices for the population."

Ukraine has been exporting electricity to Europe via Romania and Slovakia since June 2022, earning the company the equivalent of €67 million ($67 million) so far, according to Ukrenergo. The funds are needed to prepare for colder temperatures and the heating period — the purchase of coal, the repair of power plant units and power lines.

Difficult winter without Zaporizhzhia?

If revenues from electricity exports are lost, preparing for winter might be difficult. One scenario includes the nuclear power plant, and several more pessimistic scenarios don't include any of the plants, said Tsaturian. "That would be a difficult heating period, but possible to handle."

And in view of the Russian attack on the energy infrastructure, the nuclear power plants in Ukraine play a particularly important role this winter. They will likely account for an increased share of electricity generation. But taking into account the occupation of the Zaporizhzhya plant, nuclear power might reach its limits, Denys Sakva, an expert at the Ukrainian investment company Dragon Capital, told DW.

"The Ukrainian power supply system has a safety margin, but it is not unlimited. Come winter, we cannot rule out power supply failures due to capacity losses and shelling of infrastructure. And if the electricity fails, then the water and heat supply also fail immediately," Sakwa said. He believes this can be avoided by strengthening the air defense near critical infrastructure.

This article was originally written in Ukrainian. It was first published in English on August 31, 2022, and updated with the most recent developments surrounding Russia's attacks on the Zaporizhzhia power plant on November 4, 2022.