The ads in this area tout 80% covered by renewable energy tax credits!
Although I have not verified that...
I am in the final stages of modifying our solar hot water system to use our 80% gas furnace waste heat for water heating, after a successful trial run last year.
I am adding another set of copper coils and swapping out the galvanized flue for a stainless one.
Overnight heating of the house to 68f, with the outside temp at 40f nominal brought 50g of water to between 100 - 110f.
I expect the efficiency of the additional coils to bring it up to 120f +/-, eliminating the need for hot water electricity during the late fall and winter months.
That will leave about 2, at most 3 months of the year where we need supplemental energy for hot watta.
I'll post some pics.
Let me know what you find out about install costs.
In our specific location and house geometry orientation our next best alternative is wind.
http://www.windenergy.com/products/products.htm
http://www.airbreeze.com/?q=land