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"Reinventing the Solar Power Satellite" paper
Ian Stirling wrote in message ...
Robert Lee wrote: I was wondering if you worked out how high the price of oil has to be in order for an SPS project to be profitable. This is going to be as contraversial as the Drake equation. There are so many possible variables. What do you pick for launch cost? Is it $6000/Kg, or $30/Kg launched by some sort of tether. Are you using near-term 200W/Kg solar panels, or are you assuming thin-film manufacturing breakthroughs, solar-dynamic, or... What is the size of the recieving arrays, how close are they together, how big are they, can you use the land under them, do you need to keep aeroplanes out, ...... All of these are variables. It's quite easy to generate numbers that vary by a factor of at least a thousand. Do we use direct space launch, which would be the cheapest for a few GW, or do we go and capture NEOs, which would be much cheaper for a few Terawatts? |
#12
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"Reinventing the Solar Power Satellite" paper
Robert I was wondering if you worked out how high the price of oil has to
Robert be in order for an SPS project to be profitable. That's the energy component. You also have to know the price of land. Solar cells on the ground in Arizona might generate about 300 KW per acre. Call it 6 hours a day (it's more, but the amount decreases off noon), sell it at $.04/kWH, for $26k a year. A quick google found land in Arizona ("Just 1 hour from Phoenix!") for $2000/acre, and I would guess it can be had for less, especially in Mexico. If you can pay off the land with a month's operation, I think the dirt is a good cheap orbit for an SPS until launch costs drop to $1/lb and you can build a reliable power satellite in 1 ounce per square foot. I really wouldn't even worry about putting the land to other uses. Even the absolute amount of land available does not appear to be a large problem, as 150 square miles would generate enough power to run California, and 800 would take care of the difference between day and night operation across the entire U.S., eliminating those pesky "peaking" issues. Then, of course, you have to compare transporting energy via thousands of miles of wire, which is a well-understood problem (buying rights-of-way), versus transporting that energy tens of thousands of miles via microwaves, which have seen less deployment due to much larger losses, complexity, and issues with things getting into the beam (which I think are somewhat analagous to right-of-way issues). So never mind space, building and installing cheap solar cells is *the* problem. Happily, we're only an order of magnitude away (for cells I can buy today from realgoods.com), and probably a fair bit closer than that for large commercial systems. Manufacturing problems are much easier problems than negotiating with despotic thugs and their terrified citizens in, you know, the mideast. |
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"Reinventing the Solar Power Satellite" paper
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"Reinventing the Solar Power Satellite" paper
Geoffrey A. Landis wrote:
Geoffrey A. Landis wrote: For any of you with an interest in Solar Power Satellite (SPS, or SSPS) concepts, I finally received NASA Technical Memorandum copies of my papers "Reinventing the Solar Power Satellite" and "Peak Power Markets for Satellite Solar Power" from the Houston IAF Congress... NASA TM-2004-212743 Or, for those who prefer electrons, I realized it's available on the Glenn server as a PDF file: http://gltrs.grc.nasa.gov/cgi-bin/GLTRS/ browse.pl?2004/TM-2004-212743.html As I understand it, your SPS plan is predicated on ground solar cells supplementing around local noon the SPS's peak power generating times at 0900 and 1600. The SPS transmits its power to the ground solar installation, which also would have rectennas to capture the microwave beamed energy. That's an interesting idea, but perhaps I'm missing something. Why beam microwaves at all? You have a perfectly good ground solar installation, and according to Henry Spencer PV cells are fairly efficient (~50%) if the wavelength is well matched to the type of cell, so a space-based dichroic mirror array might be an equally valid form of power beaming to the ground while reducing terrestrial heating as compared to a simple mirror. The design would likely look like the dihedral array in figure 9, albeit with the dihedral pointing in the opposite direction to bounce light to the ground installation. Eliminating the microwave transmitters would reduce orbital mass while reducing ground-based cost by doing away with rectennas, not to mention calming public fears about RF leakage outside the ground receptors. Comments? Francois. |
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"Reinventing the Solar Power Satellite" paper
"Christopher M. Jones" wrote in message om... (Alex Terrell) wrote in message . com... However, the article didn't pick up on the tax raising benefit. My view is that if Governments have to raise money, better that they tax undesirable things like pollution and congestion than desirable things like income and profits. Except that a gas tax is inflationary. It taxes shipping, travel, electricity, heating, cooling. It adds to the operating costs of, well, pretty much everyone, including individuals and businesses. Which decreases discretionary income and thus consumer spending. In short, it becomes a de facto tax on income and profits. A defacto tax on the income and profits of people and firms that use (directly or indirectly) a lot of gas. Which means that it is a defacto tax CUT on the income and profits of those who structure their lifestyles and production to use less gas. Which was the whole point. |
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"Reinventing the Solar Power Satellite" paper
"Robert Lee" wrote in message ...
One other thing comes to mind, if you are pumping energy into the atmosphere, it seem that you maybe producing waste heat as well, that could also play a role in global warming, so you would still have to find a way to remove the CO2 and Methane for the atmosphere in order prevent continued global warming. Of course, the decrease in CO2 emissions could offset the waste heat produced. I guess someone would have to do the math to find out. Global warming is not caused by waste heat, it is caused by the greenhouse effect. Greenhouse gases, e.g. CO2, traps natural heat coming in from the sun, and prevents it from being radiated back to space. The amount of solar energy trapped in this way is at least thousands of times greater than all the waste heat humanity is creating. I did the calculation once a few years ago, I will see if I can find the data. I say thousands to be conservative, it could be more, I do not remember. The solution to global warming is to stop emitting greenhouse gases. That means eliminating fossil fuels, or sequestering all the CO2 underground. Once that is done we are free to generate as much waste heat as we want, it will simply be radiated out into space along with the re-radiated solar energy, with no detectable net change to the overall temperature of the planet. |
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"Reinventing the Solar Power Satellite" paper
Iain McClatchie wrote:
Francois a space-based dichroic mirror array might be an equally valid Francois form of power beaming to the ground while reducing terrestrial Francois heating as compared to a simple mirror. This was covered right here fairly recently. Quite, quite. I got here just recently, and on your recommendation re-read the older posts. Thanks. What you're missing is a limitation of ordinary optics: nothing that simply reflects or diffracts sunlight can make a spot in the sky appear brighter than the sun. The crucial function of the photovoltaics + microwave transmitter is that they make a spot in the sky with huge power per steradian. [...clear & concise technical explanation why my idea is full of beans...] Much appreciated. (wait! This is Usenet! Civility Not Allowed! YOU PESSIMISTS IGNORE THE TRUE GENIUS BEHIND MY REASONING! GALILEO EINSTEIN!! BOOGA BOOGA!) There, that should restore the natural order. Cheers, Francois. |
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