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Posted by David Sherman [72.47.9.228] on Tuesday, August 10, 2010 at 14:14:09 :
In Reply to: Re: OT Anybody know posted by gmharris [71.105.201.160] on Tuesday, August 10, 2010 at 13:58:20 :
Hydro is usually worth it if you have a good site. It's really the only "alternative energy" system where an ordinary person with an ordinary site can get several kilowatts continually. Solar and wind are very erratic, and require lots of batteries and electronics. Water runs all night and in bad weather. It also packs a lot of punch into a small space. I have two small mountain streams on my place, either of which would be good for 1 to 5 kilowatts depending on the time of year and how I developed it. It takes tens of thousands of dollars worth of solar panels to produce that kind of peak power, and that's only "peak". You need several times that, plus storage capacity, if you want that power available at night and on cloudy days. Wind isn't usually much better unless you live right on the ocean.
Hydro is definitely worth looking into if you have the site. The problem is regulations. Water is all owned by somebody. You may or may not be able to get around that by having a "run-of-the-river" plant, i.e. no dam or storage, so you're not altering the water flow below your place. There are lots of environmental rules about in-stream structures, maintaining flow for fish, keeping fish out of the intake, etc.
Quite a few people slide a small system under the radar and get away with it. Those are generally "micro-hydro" systems that use an automotive alternator to charge a battery. Even then, good engineering is important and equipment is not cheap. A tiny Pelton wheel made by Canyon Industries will run you about $3,000. Harris Hydro specializes in small turbines that are around $1,000. They have one called a "turgo", which is sort of a hybrid of a pelton and francis turbine. It's an impulse turbine, but the shaft is vertical.
The first thing to do if you're serious about this, and you want maximum power is measure your head and flow. Flow can be measured with a v-shaped notch in a piece of plywood, set up in the creek as a weir. The books have tables for converting the depth of water going through the notch into cubic feet per second. Those numbers will give you an idea how much power you might get. Next thing is to look into water rights and other regulatory issues and see if it's even possible to do it legally. Then you can decide how to proceed with the design of the thing, if it's still feasible.
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