A few years back, when I was building my house, I wanted to look into one of the whole-house fireplace furnaces. The mfg I was considering didn't have any reps in the area, but they did have a customer that had one that was willing to let me visit to see it. Well, the fireplace was impressive enough that I bought one and heated my home with it for about 10 years, altough I eventually replaced it with an outdoor boiler, but that's another story.
This guy with the fireplace had something like 160 acres in the middle of nowhere Michigan and on it was an 80 acre pond with a 19 foot drop to a stream it drained into. This guy had the MOST impressive mini-hydro plant I have ever seen: 55Kw main generator with a 10Kw back-up on a bypass loop, all controlled to hold at a steady 60Hz. Turns out he had some retired hydro engineer from the local utility design it for him. SWEEEET !
The only thing he had that most folks don't is complete access to sufficient flow AND drop.
I've given the whole self-sufficiency thing a LOT of thought as I hope to build again in a few years:
Quite frankly, as far as heat goes, the most important thing is to START with an energy efficient structure that makes the most practical use of solar gain; The sun is the best source of free heat and the less you need the easier it is to fill in the gaps where the sun doesn't do the job. Insulation, insulation, insulation.
As for electrical energy, that depends a LOT on where you live; The sunny southwest is a much better place for solar than northern lattitudes where sunlight is scarce, especially in the winter (and pay-backs are proprtionatly longer). Windmills require wind, on a fairly steady basis and not everywhere is well-suited to this either. Hydro is obviously limited to an extremely small number of locations, and permitting can be rough. The day is coming when small-scale fuel cell generators will be available, but unfortunately it looks like they will first really become available through local utilities and run on LPG (so much for independence). If somebody developes a safe, small-scale, renewable energy driven hydrogen generation and storage system THEN dependable fuel-cell based electrical independence will be a reality.
Diggem'