For those remaining in Ukraine there is a personal level of energy generation. Solar panels and batteries. The personal and portable solar panels can recharge batteries that can be used when night falls.
Rooftop panels can be installed for larger batteries. The rooftop panels might open the building up to drones and bombs, but, smaller, portable varieties can go undetected allowing greater safety.
That and subzero sleeping bags will work for the Ukrainians that refuse to surrender to these horrific and genocidal attacks by Russia.
Russia and its few allies are engaged in a multi-front war. Until Russian leadership changes and decides their tyranny is a human rights issue there is little hope for significant reprieve.
Starve the beast that is Russia and bring about an end is the only real hope for the world. It is a horrible country and cannot be allowed to continue it’s march to greater human suffering.