I have a brook that is 300 feet from the house, less if you cross the pond. The brook falls 45-50 feet into a small pond. From the top of the brook to the pond is 300'. I have a weir on the pond and have observed the flow for years. My state now has net metering and it is time to utilize this resource. Power often goes out and I have a backup generator. I would like to add 48 volt battery bank and a grid tie inverter. Current thoughts are an Outback.
Due to cost of this project I will likely spread it over more than a year. The brook dries up most years if it does this year I will do the penstock else the battery bank and inverter. I want to capture as much power as possible since I can back feed the grid.
The numbers
45 feet of head.
300' penstock needed
Flow 50 to 800 gallons per minute
Flow 800GPM+ 6+/- weeks a year
Flow 400GPM to 800GPM 6+/- weeks a year
Flow 200GPM to 400 GPM 6+/- weeks a year
Flow 50GPM to 200 GPM 12+/- weeks a year
Some years as last year it never dries up.
I was thinking of a 6" penstock feeding a small turbine building with 3 identical permanent, magnet generators. With four 50 GPM nozzles on each I could vary the output from very low to max. I would also be able to add them one at a time and with all have redundant generators for low flow conditions. I have found some permanent magnet generators that are based on alternator cases and I have found turgo turbines also. I can put the pieces together cheaper than the premade systems that are available.
I am looking for thoughts and feed back. This is in the planning stage so I am very open to suggestions.
Thanks.
John Sokol
New Hampshire