[ExI] EP and Peak oil.

Keith Henson hkeithhenson at gmail.com
Wed Apr 2 15:43:54 UTC 2008

On Mon, Mar 31, 2008 at 1:37 PM, John K Clark <jonkc at att.net> wrote:
> "hkhenson" <hkhenson at rogers.com>
>  > http://www.drmillslmu.com/peakoil.htm
>  > Even if you don't buy into peak oil and the consequences, it's an
>  > interesting compilation. I disagree on only one point, this quote:
>  > "No combination of renewable energy systems have the potential to
>  > generate more than a fraction of the power now being generated
>  > by fossil fuels."
>  >   -- Jay Hanson
>  > And most of you know why.
>  Not me, I agree with the quote. Whatever is going to replace oil it will
>  need to be HUGE, absolutely ENORMOUS!

No argument.

>  Wind farms and tidal energy
>  just don't make the grade.


>  Maybe solar energy could someday make a
>  dent in the problem, but the technology just isn't there yet.

Again, true.

>  Right now
>  it would take a solar panel the size New Jersey to replace the energy
>  dispensed by just 100 gas stations.

It isn't a large state, in fact it's ranked 47th out of 50 in area.
Still it's 22,608 sq km.  From Wikipedia, "or 0.45 - 1.35 kWh/m²/day"
from sunlight for 15% efficient solar cells.  Using the lower number,
that's 0.45 GWh/square km/day or 10,173 GWh/day,  for a solar panel
that size or 3,713,364 GWh/year.

"The U.S. used about 510 billion litres (138 billion gallons) of
gasoline in 2006."  100 stations out of 20,000 would pump about 2.25
billion liters.  "Gasoline contains about 34.6 megajoules per
liter(MJ/l)"  That's 88,230,000,000 MJ/year or since  "1 MJ = 0.278
kWh" 24,527,940,000 kWh/year, or 24,528 GWh/year.  At 50% conversion
efficiency electricity to liquid fuel, it takes about 50,000 GWh/year
to supply 100 gas stations.  That's about 1% of the output of a NJ
sized solar panel.

Looking back over the numbers, I suspect that paving NJ with solar
cells was what someone figured would take to replace the energy we use
in the US from gasoline.

Now look at this from using power sats, which get from 3 to 10 times
as much sunlight per square meter.  Using 8,000 hours per year it
would take about 600 GW to replace gasoline energy, or 1,200 with a
50% conversion factor.  At 5 GW, that's 120-240 power sats, or 2-4
year's production.  Or if you go to the 10 GW size, that takes as
little as a year churning them out at 60 a year.

>  There are about 20,000 gas stations
>  in the USA alone. And yes, I've heard of solar power satellites, but are
>  you so confident that the idea will be economically and ecologically
>  feasible  that you would be willing to invest your entire life savings into
>  the idea and be prepared to live on the streets if it failed? I'm not.

If we don't, and we are not "rescued" by the singularity, we stand a
high chance of starving, maybe better than 90% worldwide in the next
25-30 years.  "Life savings" may not have a lot of meaning when things
get that unstable.

>  And I'm all for making things more efficient, but that's not going to solve
>  the problem either, efficiency just makes energy cheaper, thus people will
>  use more of it.
>  You can fantasize about nuclear fusion (hot or cold) or vacuum zero point
>  energy all you want but the cold hard reality is that right now only 5
>  technologies have the potential to replace oil. All of them would give Green
>  Party tree huggers a tizzy fit (but then everything gives them a tizzy fit);
>  and none of them are exactly cheap, except perhaps the last if we did it
>  just right. They are:
>  1) Coal
>  2) Tar Sands
>  3) Oil Shale
>  4) Methane clathrate, (the least developed technology)
>  5) Nuclear Fission

None of these are renewable.  There was an interesting article in New
Scientist in Jan that makes the case we are within 25 years of peak
coal.  Even with breeder reactors you run out of fissionable fuel in
less time than you would think.  Part of the problem is the amount of
energy you have to feed into getting a unit of energy out.  When you
get down to mining granite for uranium, it's close to 100 percent
being fed back.

In this context a power satellite repays its lift energy to GEO in as
little as a day with the right technology.


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