As I understand from reading Vaclav Smil's “How the World Really Works”. Replacing fossil fuels by renewables isn't simple:
"we are a fossil-fueled civilization whose technical and scientific advances, quality of life, and prosperity rest on the combustion of huge quantities of fossil carbon, and we cannot simply walk away from this critical determinant of our fortunes in a few decades, never mind years."
Of course we can. Just do the calculation into TW and then that’s how much renewables we need. We built a ridiculous world war machine in less than 10 years and then a crazy space machine in the 20 years after that. Making wind and solar is kind of easy and as you did it it would get cheaper to do (as you lowered the cost of energy to 0)
Europe has no need to depend on Russia, Libya, or Turkey for energy requirements, except in the immediate near term.