Wednesday, April 6, 2016

Energy Sources for the Future - Take Your (Limited) Choices

Fossil fuels will be around as long as mankind, but there is historical reason to believe that they - like whale oil and placer gold - will be diminishing in economically recoverable supplies. "Renewable sources" - such as solar, wind, hydro, tidal, geothermal and chicken manure energies - are frankly just not going to fill the bill when it comes to an industrial economy with billions of people requiring an ever-increasing supply of energy. [For instance, energy-balance calculations reveal that the energy cost of building a solar plant exceeds the energy it is expected to capture and utilize over a forty-year lifetime.]

Fusion, as noted, would be wonderful... if it is possible as a source, and if we have the ability to develop it in the next twenty generations. Which leaves us with one proven source of sufficient energy for the world during the next several millennia: nuclear fission. There are, as far as is known today - and we know quite a bit - only three choices for fissionable materials:

Number 1: Uranium 235. This is the granddad of fission. It naturally occurs as 0.7% of the element found on Earth, and - if economically recoverable supplies are considered - is probably good for powering the world's energy needs for the next century or so. Many observers say forty years, but "Julian Simon's Law" would no doubt govern this commodity also. [Simon, Julian. The Ultimate Resource, Princeton University Press, Princeton, 1996.]

Number 2: Plutonium 239. Easily "bred" from common uranium 238, transmutation of existing stockpiles should last several hundred years at present use rates. But as Dr. Cohen points out in The Nuclear Energy Option, with breeder technology it becomes economical to separate uranium from sea water - where there are some 2 trillion curies - allowing man all the energy he needs until the sun burns out in 4 or 5 billion years.

Number 3: Uranium 233. This is the sleeper. When thorium 232 is exposed to neutrons, as in the transmutation of U238 to Pu239, another miraculous thing happens. Dirt becomes and incredible energy source. As mentioned in chapter 1, the Earth's surface averages 2.5 tons of thorium in the first foot of each square mile of area. The late Dr. Edward Teller was a strong advocate of thorium transmutation using a CANDU-type heavy-water reactor. His design would allow plentiful and inexpensive thorium to be entered in one side of the reactor, converted slowly to U232, which would be fissioned for power, with the "really spent" fuel exiting from the other side months or years later. He calculates this would give earthlings sufficient energy to provide for the next seven ice ages. [Teller is known as the "Father of the H-bomb" - but more accurately described as the defender of the free world from Soviet totalitarianism. See "CANDU Is Really Remarkable," Power Projections, May 1980.]

Add this to Dr. Cohen's four or five billion years, and we're really starting to talk about some time.