[Server-sky] [ExI] Power sats again

Thu Jul 18 01:57:06 UTC 2013

On July 17, 2013 at 7:14 PM Michael Turner <michael.eugene.turner at gmail.com>
wrote:

> "The problem with hydro in most places is that it is remote, or small,
> or destructive of habitat, and usually all three."
>
> First, something that keeps getting lost in this discussion is that I
> propose beaming power up from Earth through a microwave relay back
> down to Earth. Surely, if it's very efficient sky-to-Earth, it's no
> less efficient Earth-to-sky?

I don't think so, for two reasons. One, the problem is not really symmetric.
Antennas are more expensive per square meter up there than down here (at least
now, and for quite some time to come). So, you should expect smaller antennas up
there radiating to big farms down here. The reverse is not as efficient, unless
the uplink array is phase coherent (so it acts like one large antenna), which is
expensive AND subject to atmospheric phase changes (which you don't care about
in downlink).

It is conceivable that you could do a phased array with adaptive phase
corrections, and deliver all your RF to a small spot up there, but it will be
neither easy nor cheap, and it might not work well under all atmospheric
conditions. This would be for uplink only, the downlink wouldn't care.

BUT, that is only the one way problem. The real problem is that you want to go
_two way_.  That multiplies your efficiencies (squares them if they are equal up
link and down link), plus another factor for whatever link losses you have up
there. (For example, if you were 50 % efficient going up, and 50% going down,
the total efficiency is 25%; 25% is definitely less than 50%, and that's before
you account for losses up there.)

Regards
Marshall Eubanks

I really don't want people to lose track> of the basic idea, but (thanks,
Charles) maybe that's gotten drowned
> out by a misunderstanding of what I saying in the first place.
>
> Second, "small" and "destructive of habitat" might not be mutually
> exclusive, but in general, smaller is far less destructive. I believe
> the Sierra Club's official position on hydro is: small is good, big is
> bad.
>
> Finally, I'm trying to address "remote." Forget big dams, for the
> moment. If you have lots of (small) hydro in a remote area, and
> collect it over wires to a microwave transmission and beam it to
> space, for distribution to markets, that takes us back to my question
> of definition: since hydro power is solar, in effect, could relaying
> that power through orbit be considered a kind of SSP?
>
> And if the capital costs of starting with SSP as microwave /relays/
> are much lower, instead of with huge PV arrays in orbit, well,
> wouldn't that be the place to start with SSP?
>
>
> Regards,
> Michael Turner
>
> Project Persephone
> K-1 bldg 3F
> 7-2-6 Nishishinjuku
> Shinjuku-ku Tokyo 160-0023
> Tel: +81 (3) 6890-1140
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> turner at projectpersephone.org
> http://www.projectpersephone.org/
>
> "Love does not consist in gazing at each other, but in looking outward
> together in the same direction." -- Antoine de Saint-Exupéry
>
>
> On Thu, Jul 18, 2013 at 7:25 AM, Keith Lofstrom <keithl at kl-ic.com> wrote:
> > On Tue, Jul 16, 2013 at 07:40:04AM -0700, Charles Radley wrote:
> >> BPA argued that this was unreasonable,  however, in 2011 the FERC ruled
> >> against BPA and forced them to buy all the wind power even when there
> >> was not enough demand for it.   BPA wanted the right to turn off the
> >> wind turbines, but FERC ruled that BPA does not have the right to do that.
> >
> > Bitcoin smacks of busywork to me, but the idea of turning excess
> > energy into more valuable outputs is a great idea.  Google turns
> > a kilowatt hour of $0.05 wholesale electricity into $20 of bottom
> > line results.  Shipping raw industrial inputs is silly when you can
> > convert them into high value products with low shipping expense.
> > Even undeveloped countries ship sugar, not sugar cane.
> >
> > The usual problem with conversion of erratic sources is the capital
> > cost of the conversion tools.  Most rapidly-depreciating high tech
> > stuff does not want to be idle 90% of the time.  Water pumps are
> > examples of low tech stuff with long lifetimes that can stand to
> > be idle.  But most places where water needs pumping are a long
> > way away, at the end of expensive power lines.  We can only pump
> > so much water until we run out of useful places to store it.  The
> > problem with hydro in most places is that it is remote, or small,
> > or destructive of habitat, and usually all three.
> >
> > Regards wind energy, we have lots of power engineers here in the
> > Pacific Northwet and I sometimes attend their meetings.  We also
> > have a lot of innumerate greenoids who can't tell a watt from a
> > joule.  The interactions are "interesting".
> >
> > Here is a plot I made of 2012's 5 minute averages of regional
> > power demand horizontally, available wind power vertically:
> > http://keithl.com/wind2a.png
> >
> > A perfect power source would be a diagonal line that matches
> > instantaneous production to instantaneous demand.  Honest
> > accounting would measure power sources by their 80% reliable
> > availability, which for wind power is less than 2% of the
> > nameplate rating.  If your car or house or computer was
> > randomly unusable more than 20% of the time, you would scrap
> > them.
> >
> > Windfarms in the Northwest are touted as if they produce 4.7GW
> > all the time.  The maximum they ever produced was 4.37GW for
> > one five minute period in 2012, with an average of 2.18 GW
> > and a mode (50% availability) of less than 0.74 GW.  The
> > availability is fractal, not even as good as random.
> >
> > Electricity is valuable to customers because the power is
> > reliable, standardized, meterable, and adjustable to varying
> > demand.  An energy source's value diminishes as it loses those
> > qualities.
> >
> > At the other end of the energy usability scale is one 3600 MT
> > nuclear explosion per year.  That produces 4.2 trillion
> > kilowatt hours per year of energy, about the same as annual
> > US electric generation, but in a lethally inconvenient form.
> >
> > At some point, a technology crosses over from "useful power"
> > to "extreme nuisance", and without good rapid-response high
> > capacity power storage ( http://launchloop.com/PowerLoop ) we
> > gotta just grin and adapt to the bad decisions made by others.
> > As suboptimal as the results are, they would be far worse if
> > the decision-makers were also in charge of cleaning up the
> > messes they make.
> >
> > This email is too long already.  In the next email I will
> > discuss what this means for Server Sky, and a presentation I
> > will make in two weeks that is difficult to design because
> > of these problems.
> >
> > Keith
> >
> > --
> > Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
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