[ExI] eroei forward for kennedy, p.e.

spike spike66 at att.net
Sun Dec 23 17:00:30 UTC 2012



From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of
ablainey at aol.com
Sent: Sunday, December 23, 2012 6:16 AM
To: extropy-chat at lists.extropy.org
Subject: Re: [ExI] eroei forward for kennedy, p.e.


That's useful. Thanks Robert and thanks spike for forwarding. 





Ja!  Kennedy's first post here is great, thanks Robert.  It really has me
thinking, since I too am a big fan of BOTECs as Robert mentions in his post.
Perhaps it's a PE thing.  {8-]


Here's one I did some time ago: using all conservative engineering estimates
and reasonable energy transport efficiencies, what fraction of the USA land
area would need to be blanketed by solar cells to use that as our only
energy source?  Ten years ago, I BOTECed nearly a quarter of the land area,
assuming we do stuff like solar-energy driven biomass to alkanes so that we
get to continue using our beloved Detroits with our soul-stirring V8s and


After doing a series of those BOTECs, any realistic sustainable energy
scenario I can imagine involves waaaay more energy austerity than that to
which we have grown so fondly accustomed.  In energy conservation, the fruit
hangs an order of magnitude lower than the next higher levels of fruit.


Here's what I am trying to imagine: assume the singularity doesn't happen,
never mind for now why.  Assume Keith's vision of space based solar either
doesn't come to pass or is developed in parallel, and all our miracle cures
fail, such as controlled nuclear fusion, thorium power etc, none of that
cool stuff ever works out.  Assume away war and assume some arbitrary
population equilibrium, say 10 or 20 billion proles.  Assume the falling
water and geothermal are already mostly developed as much as they are going
to be.  So assume we are stuck with solar and wind power, but we can use
biomass to liquid fuels, not driven by combustion of the biomass, but by
external power generated by solar and wind.


With those assumptions, what does a fully sustainable energy balanced planet
look like?  If you just take the total energy production and replace it all
with solar, it comes out to something like 2e13 meters square of PVs, but I
need to revisit that calc because my memory has grown dim regarding how I
derived it over a decade ago.  A huge factor is how we will do food: will we
assume some means of turning solar energy into food other than putting it
through plants?





-----Original Message-----
From: spike <spike66 at att.net>
To: 'ExI chat list' <extropy-chat at lists.extropy.org>
Sent: Sun, 23 Dec 2012 6:03
Subject: [ExI] eroei forward for kennedy, p.e.

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