[ExI] Thoughts on Space based solar power (alternatives)

Paul D. Fernhout pdfernhout at kurtz-fernhout.com
Sat Nov 22 13:30:27 UTC 2008

hkhenson wrote:
> You are just wrong on these points.  There is *no* source or combination 
> of sources on earth that will replace fossil fuels.

Can you provide any evidence to support this point? It's also hard or 
impossible to prove a negative. There are lots of counterexamples of 
possibilities and actualities in relation to renewable energy, plus, while I 
don't much like coal power or nuclear power, there is plenty of either to 
last us centuries if we are willing to tolerate the social and environmental 
costs. And there is the wildcard of "fusion".

But I prefer to focus on renewables as I know they work and can be 
constructed with minimal environmental impact (and less and less as we 
improve our cradle-to-cradle manufacturing capacity).

Passive Solar Homes can be built almost anywhere which use little energy for 
heating and cooling for at most a small extra initial cost. Here is one 
example from about ten years ago (and it has gotten easier since):
"Toronto's Healthy House demonstrates that we already have much of the 
technology we need to begin to build more sustainable housing as the basis 
for more sustainable communities. The Healthy House has important 
implications for community planning and municipal infrastructure 
development. Do we really need to spend millions of dollars transporting 
sewage and drinking water for miles and miles? We can use solar power in 
combination with existing electrical infrastructure to reduce peak demand 
and the need, for example, to burn coal. More efforts need to be made to 
bring new technological developments in housing design and construction, 
such as those utilized in the Healthy House, into the mainstream in order to 
reduce infrastructure costs and their related environmental impacts."

Here is an entire magazine devoted to this topic:

And here is one of many companies working to reduce the cost and 
environmental impact of solar:

And PV is just one energy option. Energy efficiency, plug-in cars that are 
part of a grid, wind power, wave power, OTEC, biomass conversion, and so on. 
Here is one person who has been working towards energy alternatives for 
thirty years:
   "Amory Lovins' Rocky Mountain Institute"

The reason why we still use oil, natural gas, coal, and nuclear power, and 
accept their huge external costs in terms of pollution and security, has 
everything to mainly with politics and social inertia and vested interests 
and little to do with the possibilities of technology.

Here is a trick question: how are all of the world's homes mainly heated?
Answer: the sun, because if the sun went out they would get cold pretty 
fast. So, we are only talking about averaging out temperature swings.

The area taken up by roadways is enough to power those systems by sunlight.
  "The table below shows one estimate of the total amount of land devoted to 
roads. It indicates that in the U.S. more than 13 thousand square miles of 
land is paved for roads (about 0.4% of continental U.S.), and more than 20 
thousand square miles is devoted to road rights of way (about 0.7% of 
continental U.S.)."

So, I'll be sloppy here and say 1% to make my math easier after staying up 
all night to work on this. :-) From:
"Land area, 2000 (square miles) 	3,537,438.44"

So, about three hundred thousand square miles is devoted to roads in the USA.

"Matthew Wald has just written a news article showing the power of a 
guaranteed market to bring about large-scale construction of energy 
technologies that currently cannot compete with the status quo. Two 
photovoltaic power plants, in essence, are going to be built in California, 
covering a total of 12.5 square miles and amounting to 800 megawatts of 
generating capacity (although remember that the peak is only hit for a small 
portion of the day)."

Divide by ten for the peak effect to get an average. So, that's about 1000 
megawatts (a gigawatt) per square mile for a currently installable 
installation. So, by putting solar installations over all the roads and 
right of ways in the USA, that would produce about three hundred thousand 
gigawatts of power continuously. That is about three hundred terrawatts.

Here it says:
"The United States is the largest energy consumer in terms of total use, 
using 100 quadrillion BTU (105 exajoules, or 29000 TWh) in 2005, equivalent 
to an (average) consumption rate of 3.3 TW."

So, we have, just from roadways, one hundred times as much land area as we 
need to be all solar. Sure it's a big task, but it's a big country.

And I'm not even considering that something like 1% or so of the USA (I 
forget the exact figure) is also already devoted to energy production and 
fossil fuel mining and so on... :-)

So then the argument will devolve into discussing batteries and other 
storage systems. But would anyone who proposes strong nanotech also then 
suggest we can't make a better battery if we try? We either get good at 
making things or we don't. And we have hundreds of years of coal to last us 
until then (not that I think we should burn anymore of it than we have to, 
for the pollution costs).

Manufacturing is harder, but still possible, to figure out all the rooftop 
area. But the roadways can produce 100X what we need, so let's just use 1% 
of them for everything. In fact, if we use only 5% or so of the USA 
roadways, and had a superconducting grid, we can power the *planet*. Isn't 
sustainable energy production worth devoting at least a small fraction of 
the land we devote to transportation?

However, as I said originally, maintaining a grid is expensive, so local 
solar will drive out the grid eventually.

"In 2005, total worldwide energy consumption was 500 EJ (= 5 x 1020 J) (or 
138,900 TWh) with 86.5% derived from the combustion of fossil fuels, 
although there is at least 10% uncertainty in that figure.[1] This is 
equivalent to an average energy consumption rate of 15 TW (= 1.5 x 1013 W). 
... . For the whole Earth, with a cross section of 127,400,000 km², the 
total energy rate is 1.740×1017 W, plus or minus 3.5%. This 174 PW is the 
total rate of solar energy received by the planet; about half, 89 PW, 
reaches the earth's surface."

So, humanity uses 15TW (much as heat) and the sun provides 174,000TW, or 
about 10,000 times what we use now. We have to be *really* bad engineers if 
we can't make that work, even if our energy needs go up by a factor of ten. 
But chances are they won't any time soon.

Maybe I made a mistake somewhere and missed a decimal or two, but over and 
over you can find people saying similar things -- there is plenty of energy 
producing potential from renewables.

And my point is mainly that millions of people are working right now towards 
that end. So, regardless of whether solar space satellites go up, we will 
see enormous progress towards renewables. Even Google is putting a lot of 
money into it:
"Clean and affordable energy is a growing need for our company, so we’re
excited about launching RE<C, a strategic initiative whose mission is to
develop electricity from renewable sources cheaper than electricity produced
from coal. Initially, this project to create renewable energy cheaper than
coal will focus on advanced solar thermal power, wind power technologies,
and enhanced geothermal systems – but we’ll explore other potential
breakthrough technologies too."

And here is the deeper issue -- we are arguing here over renewable energy 
prospects, not the best way to make space habitation happen.

 > Perhaps.  But if you are going to recycle these things you need energy
 > to do it.

Which can be produced on Earth, as above.

I could point to dozens of different renewable energy technologies which are 
being worked on on Earth (biomass conversion, algae ponds producing 
hydrogen, salt ponds, OTEC, wave, wind, many varieties of PW) many of which 
are producing significant amounts of energy today. And you are suggesting 
you can definitive say all of them will fail even with another few decades 
or research operating under an ever accelerated pre-singularity pace?

 > I know these arguments.  But if you think making your own energy is cost
 > and time efficient you are just wrong.  After you have heated your house
 > for two winters, going on a third, with wood come back and talk about
 > it.  And that's not even beginning to deal with electric power.

I live in a somewhat passive solar house (heated with electric actually, 
some from hydro, some from nuclear). We live in a cold climate, but have 
lower heating costs than when we lived in a poorly insulated home with an 
oil burner. This house is not even anywhere near what can be built now. You 
can build a house that has almost very low utility bills of any kind for not 
much more than a conventional house -- it is only education and social 
inertion (and sometimes poor building codes) that hold it back. And more and 
more people are building green. Also, a lot of people live in cities where 
heating utility operation can be consolidated (even for biomass burning or 
solar thermal heat).

--Paul Fernhout

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