[heleninboodler]

Taken to extremes of solar+pumped-storage, we could end up with a situation where the earth spins more quickly in the early morning when the moment of inertia of the planet is lower because the solar panels haven't started moving all that water mass to its higher elevation yet.

[tintor]

There is always a morning somewhere!

[heleninboodler]

This is an excellent point and I can't believe I overlooked it. Obviously there could still be significant lopsidedness since places where you'd be moving mass around might not be evenly distributed, though. No idea why someone downvoted you for this observation. :D