A 20Kw wind system will be pretty pricey. Once you get above about 5Kw, talk to a vendor for specifics. Multiple smaller systems are not as efficient, but any point of failure in one part will still leave you something to fall back on. A 500 watt system with a small inverter, charge controller and one battery could be put together for about $1500 and easily expanded with additional batteries as needed. Another consideration, most wind generators are rated up to 120mph, anything higher, damage can occur, so watch those wind speeds until it is safe enough to raise them.
One thing I would recommend would be to purchase a simple electronics book that explains how generators, motors, alternators etc. work. The concepts are pretty basic to the point if you understand how they work, they can be readily built/rebuilt. One book is How Electronic things work ... and What to do When They Don't by Robert Goodman. It covers very basic electronics, but also things like TVs, VCRs, radios etc. There are many other good books on the topic available if you look around.
Offered by Steve.