Re: Norm's New Year Resolution may come true: DB may close

[RuthWeiner@AOL.COM]

In a message dated 1/3/03 11:33:56 AM Mountain Standard Time, ncohen12@comcast.net writes:


> I am in favor of phasing them out over a period of perhaps 20 years, as we phase
>
> in alternatives



In 1976, in the energy course I then taught at WWU, we did some problems assuming that 25 years after 1976, 20% of the U. S. electrical generation would be from so-called "alternative" sources: solar, wind, geothermal, biomass burning, municipal solid waste burning.  well, folks, here we are, and that 20% is not significantly more within reach than it was then.


Why?  Well first of all (here comes the sermon, so you can skip to the end), the Second Law of Thermodynamics applies to all energy conversion methods.  If the U. S. produced less than 100 MWe from coal, we'd hardly notice either the pollution or the mining effects.  Whenever any conversion method is used on a large scale, there are large scale adverse environmental effects, whether that method is solar, wind, whatever.   The up-front costs of some of these "alternati8ve methods" are considerable, and some source of funding would have to be found.  Burning trash or biomass produces carbon dioxide -- in fact more CO2 per BTU of heat produced than coal (no I'm not going to bore you all with the calculation).  Solar conversion is thermally inefficient for electrical production -- solar energy should be used for direct heating.  Unless the geothermal source is very hot, that is better for direct heating also (there is a sort of thermodynamic!

 rule of thumb that says that the closer the source temperature is to the temperature of use, the more efficient the system (and I mean the heat in sunlight as it strikes the earth -- not the interior temperature of the sun).


There's nothing wrong with nukes.  The nuclear fuel cycle is in fact less dangerous than the coal fuel cycle, because the death rate among miners exceeds any other health effect from any other electrical generating process, and less uranium is needed than coal.  As for general environmental damage, they are all comparable (that's the Second Law) so a mix of generating sources is the optimum way to go.  Besides, in my opinion, the world is going to use everything it has to produce electricity, including nuclear energy, until it is all gone.


Ruth


Ruth  



Ruth Weiner, Ph. D.

ruthweiner@aol.com