Hi Tim,
I must confess, that has bothered me a bit. Luckily eink is so energy efficient that it can be solar charged very quickly. I've got a Freeloader solar charger which is more than adequate at soaking up sunlight and dispensing it into my ebooks.
Come the apocalypse, I would rather grab an ebook and run for the hills than try to lug several kilos of highly combustible, non-water-resistant, paper. But that's just me 🙂
Thanks for the comment,
T