Circa 1973 there were several articles in the business and scientific press on the hydrogen economy. One was in Scientific American titled The Hydrogen Economy. I believe that it was the January issue. If memory serves a major theme was that hydrogen could be produced using nuclear or solar energy and used for transportation. There were of course major problems which were discussed. I was more interested in a minor theme, the epithermal concentration of minerals. As I recall it was postulated that the earth was heated primarily by gravitational collapse with an additional input from radioactive sources. As the earth cooled minerals were concentrated by epithermal deposition as they precipitated under various degrees of heat and pressure. The resulting concentration of copper, silver etc. was essentially an enormous gift of low entropy. How does one account for this gift?

This debate that keeps coming up on the earth as a closed vs open system as it relates to net energy has its merits. We're certainly not going to be importing fuel from Mars, but the sun exports massive amounts of free energy to us every day, nearly all of which we waste. If we had electrical lines running from umpteen billion acres of solar panels running all our drilling rigs and electric cars, net energy would be a moot point. A similar argument is made by Huber and Mills in their thought provoking book "The Bottomless Well: The Twilight Of Fuel, The Virtue of Waste, And Why We Will Never Run Out Of Energy". Here they point out that energy does not get used up - it merely changes forms. We just need to get more chemically clever about capturing energy as it changes forms. This cleverness ultimately would be limited only by the 2nd Law of the earth's closed system, and not even by that if you consider the sun.

But it's also true that for all practical purposes, energy comes from the ground. We don't have umpteen billion acres of solar or the chemical cleverness Huber and Mills envision and won't anytime soon. But we certainly will be running up against all the net energy problems very soon.

Thomas Edison seemed to have a handle on all this way back in 1931. He said in a conversation with Henry Ford on the rush into oil:

We are like tennant farmers chopping down the fence around our house for fuel when we should be using Nature's inexhaustible sources of energy - sun, wind, and tide,...I'd put my money on the sun and solar energy. What a source of power! I hope we don't have to wait untill oil and coal run out before we tackle that.