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Re: [Phys-l] The West Wing



Rick!

You've adopted the assumptions of the energy enterprises. By doing so you reach their desired conclusion.

It still may be necessary to depend on concentrated energy sources (C and U based power stations), but to a much lesser extent if it's done w/ more thought. In temperate climates the greatest energy demand is water heating. At the turn of the century this was accomplish in, for example, Riverside when all the homes had roof top solar water heaters before the importation of natural gas. Whether done directly or w/ a heat exchanger, they are inherently more efficient than using gas or electricity. I agree very high densities (many people housed under a small foot print) require pour stations. However, I suspect such density will become economically inviable and those cities will disappear.

Furthermore, I suspect we are very far from the possible savings thru increased efficiency. I've reported before we halved! our e bill by switching to CFLs. Including all the costs, environmental, etc., if governments were to give away CFLs they'd be ahead *. I think incandescents should be taxed at $1/W.


* Back a few decades, environmentalist suggested giving away Rabbit diesels would pay for themselves.

bc

p.s. our e use (domestic) is 4 kWh/ year. So our indirect use (manufacturing food, etc.) is 76k -- wow. so industry is the culprit.


Rick Tarara wrote:

As always, check out the 'reality' here with numbers. Let's take the Chicago area--roughly 10 million people. At the national average usage of 80,000 kWh/year (total energy use) that is close to a trillion (10^12) kWh annually. If Chicago had a desert climate (maybe it will in a couple decades due to global warming ;-) then the annual solar absorption would be about 2000 kWh/y/m^2. At a 15% conversion rate, it would require over 3000 km^2 (1300 mi^2) of photovoltaics to provide the energy. Then of course you also need a way to store the energy to provide some at night.

At some point the 'small is beautiful' group came to realize (or will need to realize) that high population density areas need high density power and nuclear IS an available technology that is safer and cleaner than coal. While natural gas is probably safer, it is not cleaner (greenhouse and other air pollution) and our proven reserves of gas are tenuous. Ultimately, cost may not be the overriding factor. Environmental impact and land use may become more important.

[Aside: I have often seen the argument that high density power is not needed for countries like India BECAUSE that country is still 70% rural. However...this misses the fact that the urban population is over 300 million people--more than the entire population of the U.S. Bottom line: distributed energy sources are too land intensive to be a viable solution unless mixed with _some_ forms of high density energy production. In the near term (50-100 years) that will need to be nuclear if we get serious about reducing the use of fossil fuels for environmental concerns.]

Rick

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Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, Indiana
rtarara@saintmarys.edu
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----- Original Message ----- From: "Hugh Haskell" <hhaskell@mindspring.com>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, May 25, 2006 11:58 PM
Subject: Re: [Phys-l] The West Wing



At 09:34 -0400 5/25/06, jbellina wrote:

Many years ago a friend got interested in what drove people to be, at
the time, strongly pro-solar and anti-nuclear. It turned out to have
little to do with technology as such and more to do with power and
the size of the technology. Solar was small, local and comfy, and
nuclear was large dark and powerful. So how do you address that issue?


That doesn't seem like too bad a characterization to me. It isn't
just that solar is warm and fuzzy, it that it is local. Distributed
power production has some advantages in efficiency--very little
transmission line loss, and the possibility of using the waste heat
from the power generation to provide space heating. Nuclear is big,
needs to be (but isn't always) remote, requiring long transmission
lines, and, compared to solar, much less safe, and then there is the
problem of the radioactive waste products that never seem to go away.

Uranium mining isn't the most pleasant occupation, either, since it
has all the usual difficulties involved in mining plus radioactivity.
I presume, however, that the manufacture of solar panels isn't
entirely benign, so on balance, that may be pretty much a wash.

Processing uranium to be used in a reactor, however, gets more and
more expensive, in both dollars and energy as the quality of the ore
declines with time. At some point, I suspect that the energy budget
for processing the fuel will be such that all of the output of the
plant will be used to process the fuel to run the plant. I think
nuclear will become less than practical long before we reach that
point, however.

The characterization was made during the "small is beautiful" era,
which, alas, seems to have passed. I still think it has great merit
as a slogan, for the idea of distributed power generation.

Hugh
--

Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

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_______________________________________________
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_______________________________________________
Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l