Ukrainian authorities have been warning citizens for months to prepare for the hardest wartime winter yet. Now it's clear why. Two weeks ago in Paris, Energy Minister Denys Shmyhal showed European partners an intercepted Russian document - a plan for the systematic destruction of Ukraine's energy grid, which The New York Times has also obtained.

The plan foresees mass attacks with up to a thousand missiles, drones and guided bombs on substations, hydropower plants, thermal power plants and heating plants. The most dangerous part is strikes on switchyards less than a kilometre and a half from the reactors, aimed at forcing the shutdown of the three remaining active nuclear power plants, the backbone of Ukraine's grid. Moscow also plans to target pumping stations and wastewater treatment plants, something it has not done on this scale before.

The goal is written down without beating around the bush: leave the biggest cities without electricity, heating and water. Kyiv, Kharkiv and Odesa are marked as the main targets, where electricity and heating supply is to be cut by as much as 90 percent and the sewage system completely disabled. The plan has three phases - first the substations on the western border through which Ukraine imports electricity from Europe, then the hydropower plants, and finally the nuclear plants. The end figure is knocking out almost 15 gigawatts of generating capacity - in other words, all the electricity Ukraine had at its disposal at the end of this summer.

A document the Kremlin doesn't even need to confirm

The New York Times was unable to independently verify the authenticity of the Russian-language document, which dates from August. But Moscow isn't hiding much. Vladimir Putin has already publicly announced extensive winter strikes on Ukraine's energy sector, presenting them as a response to Ukrainian attacks on Russian refineries. "Our partners, just like us, were stunned by such cynicism and cold terrorist calculation aimed at destroying our energy system," Shmyhal said.

Russian forces didn't even wait for the first cold days. Before dawn on Wednesday, missiles and drones hit a large thermal power plant and other energy facilities, and several Kyiv neighbourhoods were left without electricity and water. According to the authorities, that was only the start of a new campaign through which Moscow aims to break the population's morale, using stockpiles of ballistic missiles and new jet-powered drones that are very hard to intercept.

Ukraine has been preparing for months: protective structures over key substations, hundreds of millions of dollars for repairs, smaller gas turbines that are harder to hit. Citizens have been buying batteries and small gas heaters, having learned from last winter, when Kyiv residents regularly spent twelve or more hours a day without power and the upper floors of apartment blocks were left without a drop of water. Olena Pavlenko of the DiXi Group energy think tank says that after four wartime winters the grid is so weakened that surviving another feels like "running a marathon with only one lung".

Analysts warn that a few precise strikes could wipe out everything repaired over months - a handful of attacks is enough to make five gigawatts of recently restored capacity disappear. The Balkans remember winters of power rationing. The difference is that here, someone has planned the darkness in three phases, with spreadsheets and gigawatts. How many European governments will read this document as a warning, rather than as just another piece of news from the east?