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

Paul D. Fernhout pdfernhout at kurtz-fernhout.com
Sun Nov 23 04:55:11 UTC 2008

hkhenson wrote:
> At 06:30 AM 11/22/2008, Paul wrote:
>> hkhenson wrote:
> I was a firm believer in solar, wind, and geothermal energy until a few
> years ago, and I still believe they will help individuals. But no 
> combination
> of these "renewable" technologies will make a notable difference at the
> level of 300 million Americans, much less the 6.5 billion people in the 
> world.
>  ...No alternatives scale, and we're out of time. We made the important
> decision about energy policy at two critical junctures in American history:
> (1) shortly after WWII, when we created the interstate highway system
> and the suburbs to build a way of life that had no future because it relied
> completely on ready supplies of a finite resource, and (2) in 1980,
> when we dismissed conservation at irrelevant..."
>           -- Professor Guy McPherson 

What do naysayers prove without some serious calculations about the major 
alternatives? :-)

This proves not very much to me. I gave you a calculation that for less than 
the surface area we have already paved in the USA we could supply *all* our 
energy needs with the highest grade power (electricity) even though much of 
our power is only needed as low grade space and process heat. So clearly we 
as a society are capable of efforts on this scale since we have done them 
before (including digging up rocks and spreading crushed gravel and asphalt 
around to pave thousands of square miles). I have pointed out we have 
hundreds of years worth of coal (at least in the USA) with which to complete 
the transition. Why the gloom and doom then?

Sure, it may be *painful* up front for some to make the transition, but 
economically, it saves money within a decade or two. Who benefits by 
statements like "No alternatives scale,"? What is it about laying out solar 
panels one by one over 0.1% of the USA that does not scale? That is less 
area than we already use for energy production.

But that is an extreme case -- in practice we are moving to a mix of energy 
They can complement each other. For example, a home can get 80% of its 
electric in most months from a smaller set of panels, with the additional 
power made up by, say, liquid fuels derived from biomass or PV down south.

It is one thing to suggest space based solar power (with ground rectennas) 
might be more cost effective than ground based solar power somehow; it is 
another to say that ground based solar power can't possibly work on a large 

>> However, as I said originally, maintaining a grid is expensive, so 
>> local solar will drive out the grid eventually.
> So is storage.  There are fundamental physical/chemical reasons to 
> believe that storage will always be more expensive than the grid. 

That is a fair enough rebuttal. So, when the cost of local production and 
local storage fall below grid access costs, then we will see a stampede off 
the grid. And utilities will go bankrupt. :-) Since I can project that 
trend, the utilities should be planning for bankruptcy now. Fortunately for 
them, the cost of decommissioning the grid may be matched by the resale 
value of the copper? :-)

But, how can one on the one hand talk about strong nanotech doing medical 
repairs, and on the other thing good batteries won't be cheap soon?

In any case, liquid and gaseous energy carriers like methanol or hydrogen 
make easy ways to store power (but derived from renewable sources). Fuel 
cells continue to improve all the time, as do simpler systems to simply 
create and burn hydrogen an a gas.

Again, we can talk about cheap diamanoid structures on the one hand but then 
worry about restraining hydrogen gas on the other? Maybe we need to be clear 
about our timescales.

 > My
> local electric bill is broken down in about 20 classes which means 
> nothing to a non-engineer/economist.  I don't get a lot out of it 
> myself, but cost of the grid is about $20/month.

That sounds like a monthly service fee independent of the grid portion.

> Call it $240 a year.  How much storage battery can you buy for that?  If 
> you could make a case for putting in solar panels and ton or so of 
> battery, I presume you would.

I question that fee as low. You could call them I guess and ask. I did that 
once, as I have trouble making heads or tails out of my electric bill too. 
:-) Turned out they had just decided to raise everyone's rates 20% or so and 
were sort of disguising it. :-(

> So true.  But potential has to be made into real, and that's where the 
> rubber hits the road.

Lots of ongoing activity is documented here:

Or here:

The current headlines from the second link:
Headline News - Sat Nov 22 21:33:04 CST 2008
Nord/LB Closes Financing on 9-MW Solar Project
Wind Energy America Obtains Financing to Complete Minnesota Wind Farm
Sputnik Doubles SolarMax S Production Capacity
Danotek Motion Technologies Raises US $14.5M
DOI, DOE & NPS to Install Solar Systems
SunEthanol Raises US $25M for Cellulosic Ethanol Technology

I don't know what all those mean, but as a random sample it appears to 
indicates a lot of motion in wind, PV, and biomass stuff. :-)

> snip
>> 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).
> You keep going on about houses.  How much of your energy use is in your 
> house?  How much is in driving a car?  How much is in an airline trip?  
> How much in hot water?  How about food?
> http://www.theregister.co.uk/2008/06/20/mackay_on_carbon_free_uk/

I looked at part of the related book to that link:
 From a review:
   "as MacKay says, "I'm not trying to be pro-nuclear. I'm just 
pro-arithmetic." "

In the solar section it reads:
"At the start of this book I said I wanted to explore what the laws of 
physics say about the limits of sustainable energy, assuming money is no 
object. On those grounds, I should certainly go ahead, industrialize the 
countryside, and push the PV farm onto the stack. At the same time, I want 
to help people figure out what we should be doing between now and 2050. And 
today, electricity from  solar farms would be four times as expensive as the 
market rate. So I feel a bit irresponsible as I include this estimate in the 
sustainable production stack in figure 6.9 – paving 5% of the UK with solar 
panels seems beyond the bounds of plausibility in so many ways. If we 
seriously contemplated doing such a thing, it would quite probably be better 
to put the panels in  a two-fold sunnier country and send some of the energy 
home by power lines."

A few issues. First, he admits switching to solar can be done, at four times 
the price right now. So, there is no "doom and gloom", just pain. And maybe 
not as much pain as you might think because of hidden external costs of the 
current system (war, pollution, tax subsidies). Second, he discounts 
dedicating 5% of the country to energy production. Why? If that's what it 
takes to have energy forever, why is that too much? Also the UK is an 
island, why not just float stuff nearby for part of the power? Maybe a way 
could be developed to have solar panels that absorb only a fraction of the 
energy coming onto a farm field. And so on. See he just dismisses key 
information and key possibilities without serious analysis. And to check his 
"241,590 sq km (93278 mi2) ... Population 60,943,912 "
So, using wasteful US energy figures of 10kW per person, that would be 600 
million kW needed, or 600,000 megawatts. There is about 100,000 square 
miles. From our previous figures, we can today produce

1000 megawatts per square mile (peak). So we need to get 600,000 megawatts, 
that would be 600 square miles, except accounting for peak issues, say ten 
times that, or 6000 square miles. Thats about 6.4% from rounding figures. 
Or, as he says, about 5%. But, that is with today's cells, that presumably 
would get smaller with more efficient ones. Here's what it might look like:

But, a couple issues:
About half the land in the UK is devoted to 'grasses and rough grazing". So, 
for giving up 10% of that land (the worst part) the UK would have perpetual 
energy. Seems like a good deal isn't it? And if it isn't, about 15% of the 
UK is alredy urban land or related. So, this is only an expansiot by one 
third of what has already been taken. And remember, you can still use the 
land below a solar panel in various ways, if you use it as roofing.

Anyway, so even in a difficult case -- the UK -- direct PV solar can still 
work if people want it to (the Netherlands might be even harder?). And that 
is a worst case right now in expense and footprint. The real results would 
be better with a mix of technologies, solar roofs, energy efficiency, solar 
thermal, and so on.

You have a good point to calculate an energy use footprint.

Here are general percentages for major uses:

Industrial (33% overall)
22% chemical production
16% petroleum refining
14% metal smelting/refining

Transportation (28% overall)
61% gasoline fuel
21% diesel fuel
12% aviation

Residential (21% overall)
32% space heating
13% water heating
12% lighting
11% air conditioning
8% refrigeration
5% electronics
5% wet-clean (mostly clothes dryers)

Commercial (17% overall)
25% lighting
13% heating
11% cooling
6% refrigeration
6% water heating
6% ventilation
6% electronics

So, if my family was average, talking about residential use is talking about 
one fifth of our energy use. My wife and I both work at home and we have one 
car between us, so our energy use is a lot more home-oriented than average. 
But obviously we buy things and food, and a car and a house represent big 
investments of embodied energy.

On a per capita basis, we can take the US amount of 3TW = 3,000,000,000Kw, 
divide by 300,000,000 people in the USA to get about 10kW per person 
(although a lot of that is heat, not electric).

So, with the rule of thumb of multiplying by six for peak power, that is 
60kW worth of solar panels per person (in an extreme case). At 1kW peak per 
square meters sun, at 10% efficiency, that is 600 square meters, or about 
6000 square feet, or a plot about 60 ft by 100 ft.

But, that is worse case. Heat energy can be collected at much higher 
efficiency, and solar cells are being talked about in the 30% to 50% range, 
so I'd say 50% efficiency for conversion would be fairer. :-) Although McKay 
disagrees with this idea in has book. Which would mean a 60ft by 20ft plot, 
or 1200 sqr ft, or the size of a typical free standing home's roof. Granted 
for a family, there needs to be more space.

Anyway, can we conceive of every person in the USA having an accompanying 
1200 sqr feet of solar panels (heat and PV)? How much of a stretch of the 
imagination is that when the USA has approximately one car per capita? See:
Cars weigh at least about 3000 lbs typically (guessing), so we already have 
created about two to three pounds of advanced materials for each square foot 
a person needs to use to generate power. So, these figures seem within the 
scope of what our society is already doing. Here is a foldable solar panel 
that weighs about 3 pounds and covers about five square feet:
  "Solaris 52 Features"
"Overall dimensions open:  50" x 31.5"
  Weight:  3 lb 8 oz
  Max Output:  52 watts"

That's about 10 watts per square foot, or about 100 watts per square meter, 
so about 10% efficient. A little low perhaps. On the other hand, there is 
also energy efficiency -- it is cheaper to get a new efficient fridge or 
PlayStation than make panels to power the old one. Also, if we are 
generating electricity, and use it to power electric cars, we don't need as 
much energy for transportation because burning oil is only about 30% 
efficient or less in cars, whereas using electricity to move cars is near 
90% efficient, so you only need 1/3 the panels that you might think you need 
for that segment.

Anyway, these are all ballpark estimates, but clearly our society is capable 
of ground based industrial efforts on this scale. So, you can maybe see why 
I discount the ever repeated meme of "renewables do not scale". Again, who 
benefits from saying that?

Also, these are proof-of-concept calculations; real word renewable use would 
be a mix of a variety of types depending on local conditions, like wood 
(which some people like), PV, solar-thermal, solar power towers, microhydro, 
biomass conversion, OTEC, ground loop heat pumps, geothermal, algae ponds, 
wind power, wave power, and so on. And maybe even some Solar Space Satellite 
power. The biggest compelling situation I heard for SPS, by the way, at an 
SSI conference was powering aviation with it. I think there may be some 
merit to that, as aircraft could be lighter and the satellites track the 
aircraft and beam energy to it. Anyway, so there may be a role for SPS as 
one of a diversity of sources. :-) Or again, SPS might be useful for laser 
launch facilities or some other large industrial facilities which are off 
the grid. And that all also ignores this talk by Robert Bussard on 
alternative fusion energy:
Or even Cold Fusion possibilities:
A lot is happening.

Anyway, again, it is one thing to suggest space based power collection might 
be cheaper, it is another to say renewable ground based power production is 
impossible on a large scale.

Say, maybe we should let those Detroit car companies fail so we can convert 
the assembly lines to making solar panels and their mounting hardware? :-)

Of course, from a singularity perspective, energy use might rapidly go up. 
But then, why not move the computers into space and put the solar panels 
there? So, I don't think I need to solve that problem right now with today's 

Anyway, I'm going to this in some length to help resist some of the doom and 
gloom here. I actually agree there may well be doom and gloom, but that 
would only be from social issues and crazy wars, not from any technical 
limits of what we can do to create abundance for everyone even with just 
today's technology.

--Paul Fernhout

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