I am, for one, quite an optimist. Do we have everything figured out? Sure we don't. Anyway, the vector of movement is set and we'll get there solving some problems along the way as they come.
In the end, I guess, we'll still need to use some gas, etc. but that fraction will (hopefully) be small enough to come from a flexible and "better" source than Russia is.
But again, I don't have answers to everything. My PhD is not in energy, but in something else and one can become a deep expert only in so many things...