There is no problem in Battery backups, and no problem in transmissions lines. Both are solved by reversible PEM fuel cell technology.

Conversion of sunlight to fuel at the point of collection solves the problem of both solar energy storage, and transportation.

No need to put in transmission lines, if the fuel is physically transportable just like fossil fuels, and it is.

It isn't the possibility of using the sun you should be questioning, it seems to me, but what it is that drives you to not see or believe it is the only way out.