“Power generators are going to fulfill Ukraine’s energy needs?”
Yes, of course. Energy needs worldwide, are met by power generation.
You can do it with a few big generators, or many small ones, or some mix.
Ukraine has been transitioning to a more distributed mix, just as Europe has been transitioning away from using Russian Natural gas, and as Russia has been transitioning away from any pretense of rule of law.
There is no way the Ukrainians are going to get power generators into Kharkiv. That's why the residents are fleeing the city.