How many square feet will a 3 kwh solar system power?
There is no set answer to your question. The power output depends on where the panels are located and what rating of panels you get. If you use a very low rated panel in poor sun it would be possible to cover a mall parking lot and not produce 3 kwh. On the other hand, if you use a high rated panel in good sun you could fit it on the roof of a house. Some areas of the world (just by their relationship to the equator) have more capacity to produce power due to increased sun intensity. 10ftx10ft of panels in India in good orientation to the sun could be tuned to produce double the power of the same panels in moderately good orientation in Alaska.
What is the system that ants have and that we the people must emulate?
Like ants they used to lay aside foods, like them people must be thrifty.