There is also the issue that if building nuclear plants takes too long and is too expensive to be the solution, then such a project would also be too late to matter. Also transmission losses likely mean this is a solution for much less of the world population than you think. If we had a truly global lossless grid, then we would need much less energy storage to begin with.
Impracticalities aside, absurd geoengineering what-ifs are entertaining. Thanks for sharing.