That's a great idea ! A wind turbine (windmill) or solar panels on the roof of every WalMart, but don't stop there. Let K-Mart, Target, Sears, Macy's, 7-11, McDonald's, and Subway in on it too.
In fact, why not place them on the roof of every house and apartment building too ?
Just one question: Who's going to pay for them ? _________________________________________________
The biggest single year-round residential use of energy in the USA is to heat up and keep a ready supply of hot water. So the single biggest residential use of energy could be eliminated with a simple solar water heater on the roof of every house. From my own personal observation, I know that Israel is there now, but here in the USA, it's apparently not worth the time, effort, or expense ! ? !