Hopefully, ColtCarbine will give us his expert opinion. Briefly, this guy takes a water source, some gravity, and uses it (with some clever plumbing) to pump water to a storage container without using electricity. Now, if you just stuck a generator somewhere in the mix, you'd be all set. My suggestion is for people to watch the 2nd one first. If you're still interested, the first one shows you how to build it (and is very boring). There's probably more out there on Youtube.