[ExI] another excellent meaty post from robert kennedy p.e.

[ablainey at aol.com]

Sounds very promising to me. Again thanks for the input Robert.
That's an awful lot of potentially power generating real estate in the hands of the public. A lot in the hands of government and I imagine that the minor share would be in the ownership of commercial interests???. 
Considering that all those public owners or certainly the lions share will already have a grid hook up. It should be a simple case of slapping panels on roofs, grid tie inverters and generation meters. No new real infrastructure considerations other than management. Which is a nightmare without an efficient storage method. Perhaps a global grid will emerge as the solution? Two big cables around the equator, phase&neutral with all grids connected. eek! Perhaps P2P laser/microwave towers would be a better option?  
What I think is interesting is that the government owned real estate, highways, meridians, car parks and the like. May be far slower to develop. The average householder can have panels installed and be up and running in just a few hours. Mine took a few days from making the decision to installation. While it will take some seriously planning, man power and disruption to install PV on the Government land and that's without endless committees and objections. Also existing power companies generally have minimal land so have a barrier to market of finding suitable real estate for new installations. They will have trouble finding land that isn't being used for something else.
The public gets to be in first mover position. Granted most have the problem of initial outlay.The public who cannot afford initial outlay costs could in theory do what I proposed earlier. Secure credit against future generation.  

 

I think this kind of data supports my energy economy. A new installation paid for by credit secured on generation is energy economy in all but name. The debt will be paid as per the normal PV payback time, The energy cost of the PV will be paid back and any production from that point on would be cash in the bank. Aprox energy payback 4 years, initial cost of equipment paid back 7 years, plus interest if loaned so say 10. That is 14 years. A lot shy of the Guaranteed minimum 100% output life of 25 years that comes with some panels. You would still have another 11 years of maximum generation being pumped into the economy + any additional years of reduced output until they finally die. if economic to leave them there.

 Thats all at todays efficiency levels. Its realistic right now.

 

-----Original Message-----
From: spike <spike66 at att.net>
To: 'ExI chat list' <extropy-chat at lists.extropy.org>
Sent: Sun, 23 Dec 2012 22:21
Subject: [ExI] another excellent meaty post from robert kennedy p.e.



 
WOW thanks Robert, very interesting post.  Note to ExI, for some reason, Robert’s ISP is apparently fighting with the ExI server, and I don’t know how to make those things get along with each other.  Here’s Robert’s second post:
 
 
 
Spike, while you're working the mailserver issue, please re-post this brief reply to several responses.
 
WHY THE FOCUS ON OIL (per Rafal)?
Petroleum just by itself is the largest single industry on Earth, about 10 cents on the dollar of everything humans make or do.  Today, petroleum is also the greatest source of primary energy for the human race, having eclipsed coal a few years ago.  (Btw, natural gas is catching up fast, and I think already exclipsed coal also in this country last year.)
 
With my quick & dirty estimate last night, I showed the trend of the EROI figure of merit in petroleum is rapidly sliding in a worrisome direction, in a short timescale as Extropians would view time.  Since petroleum is our greatest source of primary energy, this developing situation should concern everybody.
 
ELECTRICITY.
Total nameplate capacity of the U.S. electricity grid is ~1 TW; electric generating capacity averaged over the year is just half that,
~0.5 TW.  In other words, the duty cycle of the average prime mover is ~50%. (Surprised?)
 
For the human race as a whole, multiply these figures by about 4.  
(Electricity is the most useful form of energy there is, but most people are not as well wired as we are.)  So, humanity's electric grid right now is ~4 TW peak, or >2 TW steady-state.
 
Re: "one quarter of the land area" of CONUS (per Spike).
CONUS contains 2 billion acres.  1 acre of land can host a quarter-megawatt, +/-, depending on where it is and which solar tech you're using.  So figure 2 million acres = half a terawatt to equal the steady-staate grid.  But, since solar only works when the sun is shining, obviously, the duty cycle is only ~20%.  Presupposing a decent method to store electricity storage comes along (one does not exist yet), you'd need five times that much land to meet nominal average demand.  So figure 2 million acres X 5 = 10 million acres to actually feed the grid round the clock.  That's half a percent of what we've got in the Lower 48.  More than that much is already covered with roofs, not to mention roads and parking lots.  (Roughly 100 million acres is "developed" in some way right now with some permanent
improvement.)  So, without covering up a single blade of grass or other greenspace, I figure there's enough space on rooftops that exist right now and happen to be oriented in a useful direction (southeast thru southwest azumith) to host much more than that 1 terawatt of nameplate national capacity.  You could easily double that again just putting solar carports over every parking lot (and then you'd get to park in the shade while charging your car).
 
(As an exercise, try comparing the gross revenue per square foot from PV on your roof or parking lot with the annual property tax per square foot.  You'll be amazed.)
 
ALL PRIMARY ENERGY.
This naturally leads to the question, how much land do we need to provide all energy needs via exclusively solar power, including storage?
 
Well, about as much sunlight falls on the lit face of earth (land &
sea) in one hour as the entire primary energy consumption of the human race in one year.  (Both figures roughly 500 quads.  Since this is the  
Extropian list, you can say that a quad is very nearly an exajoule.   
Heh.)  So raw sunlight::primary energy is a ~10,000-to-1 ratio. That is a lot of headroom.
 
Once transmission loss, embedded energy, and parasitic or "house loads" are factored in, thermal processes for generating electricity are roughly 30% efficient at converting the raw energy of the fuel into a useful form.  (This is improving rapidly in some sub-sectors.  
It may surprise you to learn that the electricity sector is the  
cleanest and most decarbonized of the three major end-use sectors.   
All forms of solar are still only a tiny fraction of U.S. electricity supply, but the electricity it produces goes straight into the grid without further conversion,  Furthermore, the sunlight is not counted against primary energy input, just like rainfall is not counted against hydro dams, nor wind against windmills.  Seems unfair, but that's how the accounting works, due to how primary energy is
defined.)  So to get Americans' primary power input to the electricity sector, simply triple the steady-state grid load, you'll be close enough.  Solar's penetration right now won't affect this number.  That is, 0.5 TW x 3 = 1.5 TW.
 
For most people in the developing and developed world, the primary energy partition amongst electricity/ transport/ raw heat is roughly one-third/one-third/one-third per sector.  So to get total steady-state primary power for a country, triple the number again, i.e. 3 X the primary power input.  Note that 3 x 3 is about an order of magnitude.
 
So now you have a quick means for a horseback estimate of a reasonably developed country's primary power demand to run everything they've
got: multiply their known steady-state electricity demand by an order of magnitude, and you'll be within 10% of the true figure.
 
(As I said, Americans are a little more wired than most, 40+% not 33%.  
  So, multiplying by ~2.5 instead of 3 to get American primary power for everything results in 1.5 x 2.5 = ~4 TW instead of 4.5 TW.)
 
So the average primary power to run the whole world, expressed in SI units, is something like 4 to 5 times 4 to 4.5, or 16 to 22 terawatts.
 
Remember I said we'd need 10 million acres (including storage) to run a half-terawatt grid round the clock here in CONUS, and that total American primary power is 4 terawatts.
 
We would not need 80 million acres to run everything in America, however, since the sunlight falling on PV modules does not count against primary energy consumption the way chemical fuels mined from the ground does.  I estimate that 30 million acres would enough, certainly no more than 50.  What's interesting about that latter figure is, that's the amount of land covered by asphalt just for America's 4 million miles of paved highways.  A similar amount is available in the medians and rights-of-way.
 
For the world as a whole then, 100 million acres (just 5% of CONUS) to
200 million acres (amount of active good farmland cultivated in CONUS) would do the job.
 
And remember with things like solar carports that this power production need not exclude other land uses.  There are substantial benefits re: energy security and governance with locating supply close to loads.
 
PS. And now I know what BOTEC means.
 
--
Robert G Kennedy III, PE
www.ultimax.com
 

 
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