TEG

Conservation of energy: There was a certain amount of energy in a particle smaller than a quark in the very very very beginning of time. When it blew up, it created the universe. There is a certain amount of energy in this universe. It doesn't change. Energy can be transformed into different types, but it is never created or destroyed.

Energy is conserved.
In the universe, not the earth.

We lose energy through the atmosphere (a), and we gain energy from the sun's rays(b). If a is less than b, the earth will heat up past the point at which we die. If a is greater than b, we may eventually have no energy left on earth. Right now b stands for bigger.

This is called global warming.
It scares some people enough to make speeches about it.
...I think what we need is a way to cool down...

Thermo-electric generators would let the world relax. There is always heat in the air. With global warming and everything, there seems to be more of it than usual (whatever we define "usual" to be...). Take the thermal energy out of the air, and it gets cooler. There is so much heat in the air, and more coming in from the sun, that energy supplies would sky-rocket because of the omnipresence of thermal energy. This would reduce the pressure put on gasoline and oil-filled countries. After we use it so much that the world actually cools down a couple degrees to whatever it ought to be if global warming didn't exist ("usual"), then we can split energy sources between gasoline, ethanol, which will have been perfected by the time TEGs are potentially created, and thermal energy.
Right now I have no idea how anyone would make such a thing; I just thought it would be pretty cool.