All of those options are available to us right now, they are literally being rolled out as we speak. There is a much bigger question about our ability to build nuclear on the scale required.
Honest question, do you know a serious source I can read about how this rollout is being executed? I am only familiar with European energy policy, and grid storage currently is a pipe dream, more efficient construction is very slowly being rolled out and so far doesn't make a dent in the problem, and the renewable mix being expanded is inevitably intermittent (mostly solar and wind, with the rest being negligible), as hydro is a very small component of the mix so far and in the medium term future. The only question about our ability to build nuclear is cost-efficiency and regulations.