[fecteau]

Solar power satellites have been discussed for decades. I think it's time we
start looking at them seriously. It's unfortunate that NASA has dismissed it so easily: http://www.wired.com/news/technology/0, ... story_top5

On the other hand, ESA is interested enough to have a conference on the subject: http://www.congrex.nl/04c15/

As a long time space entusiats, I believe SPS can play and important role in
the post oil peak economy. Developing the technology for SPS could also be the driving factor that keep the economy growing.

[guest]

This reminds me of a bit from (I believe) Robocop 2 or 1 (paraphrasing):

"Thousands died this morning as a malfunction on the orbital peace platform laser accidentaly fired into a crowded neighborhood."

All these solar sattelite articles conveniently neglect the astronomical amount of energy it takes to put even 1 kg of material into geostationary orbit.

And if you mention that, then proponents suggest building vast factories on the moon to make all of this stuff. Yeah, THAT'S going to happen in time for peak oil problems.

It would be much wiser to invest our time & energy into conservation, flexible electric grids powered by wind & solar (where as the amount of power produced falls the price increases for consumers and big power drawing pieces of equipment power down accordingly) and crop-waste-to-ethanol production.

[rerere]

$this->bbcode_second_pass_quote('fecteau', 'S')olar power satellites have been discussed for decades. I think it's time we
start looking at them seriously.

[Devil]

Dammit! We can't manage energy on the earth's surface successfully, so how can we manage it from space? Thank God, I'll be dead before any such hare-brained scheme could doom us to further misery.

[Licho]

Japan plans SPS in longer term. With several hundred megawats of power. It's gonna be using microwaves (not laser), with intensity on Earth just a bit higher than that of cellular phones. Therefore, antena reciever has to be big, but you can still use space below antena (it allows about 1/2 of light to come through).
Plan suggest, that it should pay itself in similar time like nuclear plant.

And regarding heating of Earth - that's a minimal problem. We don't have global warming because of heat we produce by burning fossils/using any kind of energy, but because of CO2.

[Devil]

$this->bbcode_second_pass_quote('Licho', 'J')apan plans SPS in longer term. With several hundred megawats of power. It's gonna be using microwaves (not laser), with intensity on Earth just a bit higher than that of cellular phones. Therefore, antena reciever has to be big, but you can still use space below antena (it allows about 1/2 of light to come through).
Plan suggest, that it should pay itself in similar time like nuclear plant.

And regarding heating of Earth - that's a minimal problem. We don't have global warming because of heat we produce by burning fossils/using any kind of energy, but because of CO2.

[rerere]

$this->bbcode_second_pass_quote('Licho', '
')Plan suggest, that it should pay itself in similar time like nuclear plant.

[Licho]

$this->bbcode_second_pass_quote('Devil', '
')1) Tell me how you are going to generate "several hundred megawatts" of microwave power. To generate 1 kW of CW microwave power (not pulsed) is already a challenge. I don't believe we have the technology for even a single MW.

[Licho]

Regarding the orbit - don't forget that GEO orbits are over equaor. But axis of Earth is tilted, and GEO orbit is 36 000 km high, so SPS won't enter Earth's shadow..

[fecteau]

Licho, Thanks for responding to most of the nay sayers comments.

One that you did not address is SPS versus earth base solar and wind power.
All have a place in our future. However I believe that once established, SPS will provide more and cheaper power.

As for "how to get it up there", have a look at the following link re"space elevator"
http://www.space.com/businesstechnology ... 40629.html

Another proposal would build the collectors on the moon, not on earth orbit:
http://fti.neep.wisc.edu/neep602/FALL97 ... ure36.html

We don't have a shortage of ideas. What's needed is the leadership to move
our society away from it's hydrocarbon addiction

[neo]

The earth atomosphere absorbs about 40% of the solar energy on average; but the percentage really varies from place to place. Here in Arizona there is almost no humidity and clouds, I belive the percentage should be much smaller. And the SPS also have some transmission loss due to converting electicity to microwave, the microwave being absorbed by the atomosphere, and converting it back to electricity. If we can cover half of Ariona desert with solar panel, we can easily meet the electricity needs for entire US. It will be way cheaper than building it in space. Of course the key is to make cheap and efficient solar panel, and it is already in progress.

My local power supplier SRP already provides solar power generated electricity at the rate of 525 kW ( http://www.srpnet.com/environment/renewable.asp ). Hope they can expand this project. I do believe solar power is our savier and hold the key to our future. I am a senior engineer at a big semiconductor company and I'm looking into ways to make solar cells from defected wafers.

[nero]

Would space based energy be useful if instead of sending it down to earth as pure energy instead you send down to earth finished products. heres my suggestion. You go capture an asteroid and use solar energy to mine and smelt the darn thing then send down to earth payloads of refined metals as slow meteorites.

[Licho]

Sun does not shine 24/7 on Earth and atmosphere absorbs significant ammount of energy. It's far more efficient to transmit it from space, even with relatively low efficiency conversion to MW and back. (Microwaves on this frequency loose only minimum energy in atmosphere). However, building costs for such thing are hug. Countries like Japan, don't have many excellent sites for ground solar farms, that's probably why they consider such extravagant plans. Some european scientists want to build solar plants over northern Africa, due to lack of suitable places in europe..

Nero: I don't think that there such thing as "slow meteorite"

[Devil]

I'll believe it when I see it, and that will be from six feet under, if ever! Even if it were to materialise, I could never hope to pay the cost price for that energy.

[JohnDenver]

Interesting article on a new approach to power satellites.

"The new communications satellites will orbit at an altitude of only a few hundred miles. Instead of hovering above a spot on the equator, low-orbiting satellites zip around the globe in as little as 90 minutes, tracing paths that oscillate about the equator, rising and dipping as many as 86 degrees of latitude. Because they are closer to the earth's surface, the solar collectors on the satellite can be a few hundred meters across rather than 10 kilometers. And because the microwave beams they generate would spread out much less than those from geosynchronous satellites, the ground rectennas could be correspondingly smaller and less expensive as well. By piggybacking onto these fleets of communications satellites--and taking advantage of their microwave transmitters and receivers, ground stations, and control systems--solar power technology can become economically viable."

http://www.spacefuture.com/archive/beam ... orld.shtml

[Jack]

Neat idea---one would think that it would be an ideal way to generate power in isolated areas instead of using long transmission lines.

[Concerned]

Sounds ok but prohibitively expensive.

How many satellites do you need in orbit to produce say 2%-5% of global power consumption how much will each satellite cost. How much energy to build and maintian such a system.

Personally it sounds like a big energy sink, nice theory but impractical.

The solutions we should be pursuing are more efficient use of existing fossil fuel resources and bio fuels such as that being developed at Iogen. http://www.iogen.ca/

Long term we need to focus more on fusion power spend less money of weapons more on research into energy. My 2c worth.

[small_steps]

$this->bbcode_second_pass_quote('Jack', 'N')eat idea---one would think that it would be an ideal way to generate power in isolated areas instead of using long transmission lines.

[Guest]

This proposal is so full of holes it seems to me a distraction from addressing the issue of sustainable energy supply.

One such glaring hole is persuading the public that it's a good idea to have gigawatts of microwave energy being beamed at receivers on the planet from hundreds (thousands?) of satellites, any of which are liable to stray or get knocked off course, potentially irradiating God knows what population centres.

Another is the utterly prohibitive cost of public liability insurance against such an event.

A third is the predictably untenable money, energy & CO2 expenditure per unit of power supplied.

In the absence of global economic growth post peak I don't see who exactly is expected to bankroll such whimsy. In case anyone hadn't noticed, America is heading for bankruptcy. Broke. No credit-worthiness. Bust.

For me this sort of proposal is a further evidence that while one major chunk of the space industry is for military escalation, another is for distracting the population from the damage being inflicted on the only significant vessel we're ever going to have: namely the earth.

The propaganda appears to be: "Why give a damn - when we've wrecked this planet we'll go find another one !"

Backstop

[Ted]

Beaming power through space via microwave or laser is clearly more efficient than passing it through the atmosphere, and much more efficient than using power lines.