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The End of the World

Or, at least that of the Northern Hemisphere, occurred in September of 2005.  If you are in said hemisphere and didn't notice, it's for the same reason that stock market statistics have predicted nine out of the last three recessions.  I have a friend who reliably, reasonably, and frequently predicts disasters.  Normally they are disasters of the economic and military persuasion, but my friend is nothing if not ecumenical.  In this case the disaster would have been the explosion of Yellowstone National Park, which, if you're not aware, is a giant volcano.  How giant?  Think thousands of times more destructive than Mount Saint Helens.  Think several times more powerful than Mount Tambora, which was the largest eruption in the last couple of centuries.  Plus, it's in a location guaranteed to do vastly more damage.  If it were to erupt today, much of the United States and Canada would be covered in a blanket of volcanic ash from inches to metres thick.

Which brings me to the point of this blogitem:  Energy.  We will very shortly know for sure whether Yellowstone erupted today.  (My bet is that it won't.  I'll even give good odds.)  But it will erupt eventually.   It erupts (very) roughly every 600,000 years, and it has been (very) roughly that long since the last one.  (I'll still give you good odds.)  When it erupts, an enormous amount of energy will be released very quickly, enough to propel cubic miles of rock high in the sky.  Where does that energy come from?  Nuclear power!

Yes, natural uranium, and even the potassium in bananas yet ungrown is decaying under your feet.  The reason that the center of the earth is hot is that radioactive minerals with multi-billion year half-lives are decaying, and in doing so are heating the earth.  Unlike a sporting orb or other man-made spherical object, the earth has a lot of insulation, what with its being eight thousand miles in diameter and all.  So it gets hotter and hotter.  And occasionally that energy manifests itself on the surface by volcanic eruptions. 

How much energy are we talking about?  Let's grab a factoid from the web:

Explosive eruptions are best compared by recalculating the volume of erupted volcanic ash and pumice  in terms of the original volume of molten rock (magma) released (shown in this diagram by orange spheres). On this basis, the 585 cubic miles (mi3) of magma that was erupted from Yellowstone 2.1 million years ago (Ma) was nearly 6,000 times greater than the volume released in the 1980 eruption of Mount St. Helens...  (From Solcomhouse)

Let's say that this was spewed into the stratosphere, or about 8 miles high.  How much energy does that require?

  • A kilowatt hour will lift a 2.7 million pound weight one foot into the air.

  • A cubic foot of rock weighs about 150 pounds.

  • A cubic mile of rock is about 147 billion cubic feet, or about 22 trillion pounds

  • So, to lift a cubic mile of rock one foot requires (22 trillion / 2.7 million ), or about 8 million kWh, the output of a large utility power plant for about 8 hours.

If it takes 8 hours to get this chunk of rock one foot up, it would take a full year's power output to make it to a thousand feet, and 40 years to get to the stratosphere.  Of course, getting the other 584 cubic miles up there, too, would require that many additional power plants.  The annual energy consumption of the world is about 16 million GWh.  If all that electricity were harnessed to lift the rock that Yellowstone would spew into the stratosphere, it would only make it up to 3400 feet in a year, and require about 15 years to accomplish what the eruption would do in a minute.

But Wait!

Didn't you say that Yellowstone erupts only every 600,000 years?  Yes, and I also implied that the amount of energy required to accomplish the rock-throwing part of the eruption would only require all the planet's power for only 15 years.  While I don't mean to imply that throwing rocks is the only aspect of the Yellowstone energy budget, it clearly is a big one.  So even if I'm off by an order of magnitude or so, you can see that while there's a lot of energy involved here, the old "titanic forces of nature" aren't that titanic!

If you think of Yellowstone as a big battery that's being slowly charged, and then is suddenly shorted out, you'll be using a poor metaphor but one that is nonetheless useful.  At least in terms of quantity of energy, it would seem entirely reasonable that an ambitious engineering project might be able to drain the energy being built up in the Yellowstone supervolcano.  If a cluster of geothermal power plants were built there, they would have about 256 million GWh of stored energy to draw on, and to dole out at the rate of, say, 1 million GWh per year, the equivalent of 100 or so utility power plants.  Decreasing the stored energy would decrease the danger of eruption almost immediately, and the energy withdrawn would supply a good percentage of the power requirements of the United States.

So, once again I have solved a big problem and saved the world.  And once again you (and I) are invited to ask:  Is this another Richardian megalomaniacal delusion?  Am I right and is the government purblind to have not yet begun this project?  Or, for that matter, have they in fact begun it?  If I were an expert on geothermal power with a degree in vulcanology, I might be able to answer that with some assurance.  In fact I know almost nothing about either, which is why I'm thinking outside the caldera.  Perhaps I'll violate the "no research" rule and get myself a clue or two.  Someday soon.

2006
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