SVreX wrote:
Jensenman wrote:
The 'low head' turbines on that page I referenced capable of powering a whole house were actually very reasonably priced, IMHO. For instance a 3kW system is $5250.00 and there are larger ones available, or they can be 'stacked'. Of course they don't include the penstock, dam, etc. I see no reason a system big enough for an average house couldn't be 'grassroots built' for about $50-$75K. Assuming, of course, that you already have a piece of property with a stream capable of powering the thing.
OK, I'm confused.
The average US home uses between 1kW-hour and 2 kW-hours per hour. 5kW-hour should be about sufficient for (well managed) peak loads.
Your 3kW system is $5250, but you are suggesting $50-$75K for a "grassroots" system. HUH? Why would you need 10-15 times the amount that can be generated for $5250? Why would you spend the ENTIRE cost of a house for a "grassroots" electrical system? Did you add a digit???
I'm figuring the cost for a small earth dam to achieve ~12 foot head (that's low end cost if everything's perfect, it could be higher if the site is not ideal), a concrete or steel tailrace to funnel water to the penstock, a concrete pad and building to house the turbine and gennie, then a sluiceway to get water back to the stream. Then there's wiring to the house, an auto transfer switch to push power back into the grid, etc. I'm also figuring at least 10 kW (15kW would be better but might invlove a much larger dam etc) for the reasons Toyman mentioned. In the middle of summer the A/C is going to run a LOT and every time that sucker fires up there's a threefold jump in power usage for a moment. Now if the A/C, refrigerator, air compressor and my plasma cutter all fire off at the same time it would be nice to have the extra capacity. 
The best thing about this whole system is that during my off peak times (like all day while I was at work) if the thing is running wide open it would be making me money as it pumps power back into the electrical grid, way more than a solar setup. it might not make enough to pay for itself, but there's another angle: if there's an ice storm or similar now I have heat, lights, cold beer, TV and the stuff in the refrigerator doesn't spoil. Hard to put a price on that. 
