energy

I just attended a one day class regarding zero net energy. Turns out there are at least four ways to define this. It can be as simple as getting your power bill to zero by feeding in enough on-site-produced energy to zero out what you use from the grid. OR you can be zero net energy if your produce enough on-site energy to cover the amount of fuel it actually takes to produce the off-site energy you use.

So.... remember the slogans 'a chicken in every pot', 'a car in every backyard'? Well, why not "solar panels on every roof"???? Obviously in real life, these may not be possible for EVERY situation.  But why not strive for such regarding solar panels? Why not require it for every roof of either homes or businesses where it is feasible to produce electricity and hot water?