Well, I did work with solar cooking too in Chad. Chad seems to be the best place in the world to develop solar energy (360 of sun/year, average 48 degree celcius...).
Unfortunately we came to the same conclusion than Dayuhan.
One of the difficulties we faced was that it was changing women habits and children integration into the family.
I know, sound pretty much like a stupid scholar stuff but in fact, now I see it as obvious.
Coocking activity is not restricted to the act of preparation and putting stuff in the pot. It is also an exchange and learning time between mother and daughter, between women... Coocking activity starts with collecting water, fire wood and end up with women gathering together in a non men accessible space to exchange about their life, their difficulties...
In Somalia I had the same experience. The coocks in our camp, 2 young women, were taking the advantage of the kitchen men exclusion to listen to hardcore gangsta rap, comment on young men... Basically doing all what their families, elders and religious leaders forbide them to do.
What we did in the Chadian refugees camps was to provide special firedevice with estremely small entry to fuel them with wood. This had the advantage to reduce wood consuption (like divide it by 5 to 10) and as it was just a way to prepare the fire pit, it was sustainable (Was mostly working with nomads from Dafur stuck in a refugee camp).

For the wind mills in South america, I am less doubtful. And it looks like a good idea. But be carefull of the effect on small trade like charcoal and firewood. But I must say that I have no experience of South America, not even put a feet their for vacations.