Ukraine was still struggling to restore full power on Tuesday, nearly a week after a wave of Russian missile strikes that damaged energy facilities across the country.
National power grid operator Ukrenegro said the electricity deficit had risen slightly from Monday following emergency shutdowns at several power plants and an increase in consumption as winter sets in.
"As of 11:00 a.m. on November 29, electricity producers provide 70% of electricity consumption in Ukraine. The current capacity deficit is 30%," Ukrenergo said on Facebook and the Telegram messaging app.
"We emphasise that the general deficit in the energy system is a consequence of seven waves of Russian missile attacks on the country's energy infrastructure."
Russia has carried out regular missile bombardments on Ukraine's energy infrastructure since early October, with damage accumulating as temperatures drop. The last big wave last Wednesday caused widespread damage.
Foreign ministers from the NATO military alliance meeting in Bucharest this week were due to look for ways to help restore power and heat in Ukraine.
DTEK, Ukraine's biggest private electricity producer, said on Monday it would reduce electricity supply by 60% for its consumers in Kyiv as temperatures hovered around zero degrees Celsius (32°F).
The government has asked consumers to be conserve energy by to prevent the need for more emergency blackouts and help repair teams to fix the damage.
Ukraine says attacks intended to cause misery to civilians are a war crime. Moscow says it is attacking legitimate military targets.
(Reporting by Aleksandar Vasovic and Kyiv newsroom; Editing by Timothy Heritage)