Republicans are clamoring for more oil and natural gas drilling; indeed, they campaigned (and lost) partly on that issue. President Obama is calling for greater use of wind and solar power, and sometimes more hydroelectric power as well. Other groups that only seldom appear on the radar of the mass media are pushing for more nuclear power; they occasionally get lip service from an elected official.

What nobody, or almost nobody, is talking about is the immense and varied benefits that would accrue from yet another relatively little known, clean, renewable, and inexpensive energy source - the ground under our feet.

This energy source actually derives from the fact that while the air temperature gets very hot in the summer and just as cold in the winter, just a few feet underground the temperature remains almost constant. As a result, there is often a large difference between the air temperature and the underground temperature. If the heat from the ground can be made to flow into the cold winter air, and the summer heat in the air be made to flow into the cooler ground, that heat flow can be tapped and converted into a usable energy source.  read more »