The head of the Mykolaiv regional military administration, Vitaliy Kim, has asked local businesses to switch to night work hours.
"I ask enterprises to switch to night shifts, except for those with mobilization assignments," he said on Facebook.
He warned that if the regional energy company decides to distribute power using "telephone law", it will have to explain this to the Security Service of Ukraine (SBU).
As of 5 December, Mykolayiv Region plans to review its shutdown schedules.