Saturday, October 08, 2005

Energy 101 – The Basics

The Common Misconceptions of Peak Oil – V
(a continuing series)

I started this series over a month ago with this post. In the meantime we have had two hurricanes and skyrocketing oil and gas prices. However, my high-school-aged son keeps bugging me to finish this so here is the next installment.

First of all, let’s get down to basics and talk about where energy comes from. From the standpoint of pure physics, 99.9+% of the usable energy on the earth comes ultimately from nuclear fusion or nuclear fission reactions (a tiny amount comes from gravity [e.g. tides] but let’s forget about that for now). Most of this, of course, comes from fusion reactions on the Sun which transfers an infinitesimally-small part of this fusion energy to the earth through electromagnetic radiation. Much of this radiant energy is then transferred and stored on the earth through radiant heating of the oceans, land masses, and atmosphere. It is through the uneven radiant heating (and cooling) of the earth that we get weather, wind, hurricanes, ocean currents, rain, rivers, hydroelectric power and wind turbines.

However, in addition to storage of solar energy through heating, some of it is also stored as chemical energy through the photosynthetic process. Most of the chemical energy created by photosynthesis is liberated through oxidation and decay (through biological and non-biological processes) a short time (months to tens of years) after the radiant energy was fixed as chemical energy. However, some of this photosynthetically-created chemical energy ends up being stored for the long haul (tens to hundreds of millions of years) through burial in anoxic environments. It is through this process we have coal, oil, natural gas, oil shale, tar sands etc.

The other type of basic energy source that we have on the Earth is energy from nuclear fission. This, of course, is where we get energy for “nucular” power plants, and what caused Chernobyl, Thee Mile Island, and Hiroshima. However, this is also the main source of heating within the earth itself, and without it the earth would be very cold indeed. Moreover, without it we would not have any oil, gas, coal or probably any life on earth at all.

If I have you confused, let me explain a little more. The rock that makes up the majority of the earth’s crust and mantle contains small to minute quantities of minerals with radioactive elements that comprise them. These minerals are dispersed throughout these rocks. They are more concentrated in rocks that make up the continents (granites etc.) than in the rocks that make up the oceanic crust and mantle.

The radioactive elements in these rocks (Uranium, Thorium, etc.) are undergoing constant radioactive decay. As they decay, they emit radiation. That radiation, as it occurs in deeply-buried rocks, does not escape, and is turned mostly into heat. This heat is the fuel that drives the motor for plate tectonics, causes volcanoes to erupt, creates geysers in Yellowstone, and keeps the earth nice and toasty warm below the surface. Without the constant, ongoing radioactive decay throughout the earth, only the surface of the earth, where the sun was immediately shining, would be even the slightest bit warm and the rest would be cold, cold, cold.

Now I have serious doubts whether any life as we know it could live on the earth without this constant fission-heating, but for the sake of argument, lets assume it could and that photosynthesis would continue on at the same rate that it does today. Without the geothermal heat of the earth, though, there could be no oil, gas, or coal. The application of geothermal heat over millions of years is what is required to turn dead and buried flora and fauna into these energy sources.

OK, so where are we going with this? Let’s summarize.

1. Effectively all energy on the earth comes from nuclear reactions
2. Nuclear energy is a good thing, so get over your phobia about it.
3. All other energy sources are derived from nuclear
4. Both fusion from the Sun and fission from inside the Earth is required to provide the energy system and all life that we have on the earth today.
5. When discussing energy sources keep in mind that with each energy conversion you get away from a nuclear reaction, the more inefficient the energy source will be.

Next installment – “alternative” energy sources.

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