From: steinly@topaz.ucsc.edu (Steinn Sigurdsson)
Newsgroups: sci.environment
Subject: Re: --UCS Offers New Energy Policies
Date: 13 Oct 92 18:11:15
Organization: Lick Observatory/UCO
NNTP-Posting-Host: topaz.ucsc.edu
In-reply-to: Tom Gray's message of 13 Oct 92 06:20 PDT

In article <1466601810@igc.apc.org> Tom Gray <tgray@igc.apc.org> writes:

   <responding to Steinn Sigurdsson>

     SS1>Wind is never going to be more than 10% of capacity on US scale
     SS1>demands (ie some small countries may use it for greater fraction
     SS1>of capcity)

    TG1>But of course you cannot say this.  It's like saying nuclear
    TG1>reactors can never be made safe.

   SS2>No, it is a quite different argument. I know the power available
   SS2>in the airmass over the continental US and I know the current
   SS2>power consumption of the US, I then estimated what fraction of
   SS2>the land area could be dedicated to wind power and what the
   SS2>turbulent mixing scale (vertical) is in the atmosphere.

   Fine.  If you'll provide some numbers, I will
   run them by Pacific Northwest Laboratory's experts.  PNL is the national
   lab that released a study in 1991 stating that US wind potential totals
   approximately 10.7 trillion kWh, using 13.5% of available land area.

I contend that using 13% of the available land area for wind
power production is completely insane. Realistically you're
not going to allocate more than 1% of the area.

   SS2>        There is certainly enough power in the wind to provide all
   SS2>of the US's needs, but only a small fraction can realistically be
   SS2>tapped. The absolute limit is the point at which you start
   SS2>directly affecting climate, the practical limit is well short of
   SS2>that.

   Yes, I don't think I am talking about either of these limits.  I
   suspect a discrepancy in the numbers.

There is one discrepance I discuss later, note I did not say
that there is not enough power in wind, I said the realistically
available fraction is too small.

    TG1>A good, credible study of wind in the UK done a few years ago
    TG1>by Michael Grubb, who is now with the Royal Institute of
    TG1>International Affairs, found that approximately 1/3 of
    TG1>that country's electric power could be supplied by wind before
    TG1>penalties to the rest of the grid became unacceptably high.

   SS2>If I remember the UK figure on lots of off-shore wind plant,
   SS2>it is also relatively exposed and has reasonable wind potential.
   SS2>Try the same calculation for Germany or northeastern US.

   It's true that the UK's wind potential is greater per unit of land
   area than that of the US.  However, the US still has many areas with
   excellent wind potential.  I agree with you that wind's potential
   in Germany and the northeastern US is limited, given currently
   available storage and transmission technology.  I don't agree that
   its potential for the entire US is limited to 10% of electric power
   capacity, which is essentially your original statement.

    TG1>So we can take that as an approximate upper boundary, although

   SS2>Grid variability is not the only factor. Also note that the UK
   SS2>is pretty much a single grid, the US is much bigger and less well
   SS2>tied in.

   Certainly, but this is back to the "never say never" issue.  I don't
   think it's reasonable to say that these technical limitations will
   forever constrain wind energy's potential, any more than it is to say
   that nuclear reactors can never be made safe.

Sorry, I was under the impression we were considering realistic
scenarios for the next few decades, note that for example that in
principle far more hydro power could be tapped if you were willing
to damn every sizable stream - some several times - and
manage runoff, there is enough power there, however to do so
is simply not practical.

    TG1>studies by Lockheed and General Electric in the late 70s both
    TG1>returned figures of ~1 trillion kWh annual potential for the US,
    TG1>which is a little more than 1/3.

   SS2>grid capacity is 1TW, that's 9 trillion kWh/yr, so you're looking
   SS2>at more like 10%, which is what I said...

   Hmmm, that's interesting.  Total consumption has not yet exceeded
   3 trillion kWh/year. 

You're right, grid is more like 800GW - I use the 1 TW as an
easy to remember number starts getting bad for factors of two
we're arguing over. Also also grid generation is indeed about
3 T kWh/yr, _all_ US energy consumption is 9 T kWh/yr.

	 But at present, if you're willing to go along
   with 1 trillion for wind, I'd be inclined to accept.  Hardly a trivial
   power source.  At that level, it would be producing about four times
   what nuclear is producing today.

so would you use it to retire nuclear plants or fossil plants?
Wind power clearly has a contribution to make to grid supply,
I think however you vastly overstate your case for how much
us readily available or can be put online on reasonable time scales,
particularly if you want to penetrate the market far enough that
you need to reconfigure the grid to match demand and supply.
I'll happily grant wind 10% of the grid, although I'm not
convinced that it's cost-effective beyond 1-3% and it really
irritates me that environemntal concerns are dismissed with
a "the land will still be available for agriculture", never
mind bird kills and the fact that windmills are big&ugly.

    TG1>Without investigating these possibilities, setting an arbitrary
    TG1>figure of 10% for wind's contribution is, as John McCarthy is
    TG1>so fond of saying, talking nonsense (even though 10 is a number).

   SS2>Why do you assume that I did not consider the relevant factors?
   SS2>If you can provide a number that contradicts my estimate I'll be
   SS2>happy to reconsider and look at what I might have overlooked.

   I assumed you did not consider the relevant factors because they were
   not mentioned in your original statement, and because I felt your
   original statement was in error.  I continue to hold that opinion.

Hmm, I actually posted the gist of the assumptions I used a couple
of months ago, I do admit that I underestimated grid supply by a
factor of three (sanity check that E = Pt didn't work, forgot that
grid supply doesn't have a 100% duty cycly :-(  ) but I strongly
contend that the total wind potential calculations do not
allow for real world limits on what can be acceptably extracted,
storage doesn't change my argument much, as inefficiency storage
loses you a factor of 2-3.

   A number which appears to me to contradict your estimate is provided
   above.  Let's do pursue this and see if we can agree on the underlying
   facts.

*  Steinn Sigurdsson   			Lick Observatory      	*
*  steinly@lick.ucsc.edu		"standard disclaimer"  	*
*  I know people whose idea of fun				*
*  Is throwing stones in the river in the afternoon sun		*
*  Oh let me be as free as them					*
*  				- BB 1986			*



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