I was recently watching
a video where Curtis Stone was giving the specs of his off-grid solar arrangement. He mentioned the output difference between a good day in the summer (where he is desperately scrounging for ways to use the power) and the worst day in winter (when he has to run diesel backup) is roughly 100x the power!
I guess I always expected some seasonal fluctuations, but, wow!
For the excess, there's the obvious and expensive solution of throwing more batteries at it, and some of the alternatives like pumping water uphill (which he discusses).
I remember reading an article one time (can't find it again, and google is no help) that proposed a different way of looking at excess electricity. They proposed the idea of looking at manufacturing as an embodied store of energy.
For example, whenever the sun is shining and the batteries are full, you use the power to run a CNC and have it a make bunch of cutting boards.
There are other things, too, like you could make hydrogen or some other fuel gas... maybe figure out a way to automatically feed a chipper to make bark chips... Ooh! Or some kind of auto-fed log splitter that splits all your firewood for you!!
(Of course, the best options are the ones that run on their own with the least possible babysitting.)
I think there are a lot of possibilities looking at things this way. What other ideas you can think of?