Thursday, July 26, 2007

Energy From Space to Your Car


The concept of Solar Power Satellites has been around at least since Dr. Peter Glaser in 1968. Sunlight in Space is 8 times more intense than at Earth's surface. If large solar arrays were built in geosynchronous orbit, the energy could be beamed to Earth via lasers or microwaves. So far the idea has been considered impractical because of cost. With the rising cost of energy, SPS has been gaining attention again.

As with many new technologies, the military may take the lead. To power all their gear, infantrymen use the equivalent of one AA battery per hour. Many lives have been lost delivering fuel convoys to soldiers, not to mention USS Cole. The National Security Space Office (NSSO) is counducting a serious study of SPS. They are looking for breakthrough ideas.

The NewSpace2007 conference in Washington was presented by the Space Frontier Foundation, which has been studying SPS for years. Saturday at the conference I had opportunity to talk with USAF Col. (select) Coyote Smith, chief of the NSSO's future concepts division. He has been leading an online forum soliciting ideas. Col. Smith envisioned kilometer-wide collector fields located outside major cities. He hopes to have a SPS system online by 2050. (He likes the spacesuit too.)

I was able to point out that if someone in 1907 had lectured about the future of energy it would have been about coal and oil. Yet in 2005, out of the limelight, someone had already written E=mc^2. 40 years later we had atomic reactors and an atomic bomb used in combat. First we must go beyond dead ends like "dark energy." The power of free thinking will lead to technological surprises.

If in 40 years we have tiny Black Holes in the laboratory, their energy could be tapped. Even nuclear fusion converts only 0.7% of fuel into energy. A Black Hole can convert matter into radiation with 2 orders of magnitude greater efficiency, approaching total conversion. The food that a human eats in a year could provide all the electricity needs of the United States! Any sort of mass could be used for fuel, even old AOL disks and issues of National Geographic.

Solar Power satellites have not been deployed because of the immense construction costs. An SPS constellation powering the US would require 30-40 satellites, each with kilometers of solar arrays. Note how much trouble it has been constructing one space station in low Earth orbit. Black Hole energy would require just one satellite without all those solar panels! The power of thought is far greater than anything humans have imagined.

In other news, Toyota has announced it will be road testing a plug-in hybrid version of my Prius. Such a car could get at least 100 MPG, more if you only drive short distances. Plug-ins and battery cars can get their power from solar, wind or geothermal plants without any petroleum in the loop. Your 21st century economy could be clean and all-electric.

UPDATE:
Tommaso Dorigo has an excellent post on Black Hole production.

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7 Comments:

Anonymous riqie arneberg said...

Unless the LHC is able to produce black holes, (a fiinite possibility), we have no idea how to go about capturing one, never mind confining it.Meanwhile, E=MC^2 remains valid. and we know how to build nukes. It is time we got over our irrational fear and use proven methods to combat global warming.

3:54 AM  
Blogger Freiddie said...

Matter -> Energy, something I really contemplated about. So is this how a direct conversion (little loss) can be done? Black holes = the answer?

10:55 PM  
Anonymous Ed said...

Sunlight in Space is 10 times more intense than at Earth's surface.

What do you base that on?

Here are the approximate numbers as I understand and remember them. In space (at about 1 AU from the Sun) the solar flux is about 1300 W/m^2. On the Earth's surface at the point directly below the Sun (where the Sun is overhead) the flux is reduced, by absorption by the atmosphere) to just over 1000 W/m^2. Averaged over the whole surface of the Earth, including the bits in the dark and the bits where the Sun is near to the horizon the average comes out to about 250 W/m^2. That's the solar radiation received directly and scattered. There's an additional, smaller, downward flux of thermal infra-red from the atmosphere.

So, the most I can make the ratio is about 5.2:1 and even that's stretching the point rather misleadingly in that most people won't expect to halve the surface value because nearly half of the time it's night.

Also, even if the insolation on a square metre of surface well away from the sub-solar point (i.e., somwhere where the Sun is low in the sky) is not that high, you wouldn't lie a solar panel flat but would set it pointing toward the Sun or at least toward the equator (e.g., south in the northern hemisphere) so you'd get a higher insolation per square metre of panel than per square metre of surface.

3:34 AM  
Blogger L. Riofrio said...

10:1 is a usual rule of thumb used since the 1970's. Beyond certain angles of incidence the efficiency of a solar panel approaches zero. Don't forget cloudy days.

10:27 AM  
Anonymous Ed said...

Don't forget cloudy days.

Fair point, though transmission from, say, the US south-west to the rest of North America or from North Africa feeding into the European grid seems likely to me to be a lot cheaper than transmission from GEO.

Would love to see a pair of conducting space elevators for this, though.

2:28 AM  
Anonymous Anonymous said...

SPSs were studied during the 80s. The result was that without an in place space infrastructure, it's more cost effective just to locate the solar panel farms in the mojave desert.

4:38 PM  
Anonymous solar power said...

I hope that 21st century economy could be clean and all-electric. And I believe that solar power has big potential. I think that this is a good start for the idea of a technology that can be improved with an excellent promising future. Because if we can use the sun as a source of energy for a cleaner and healthier environment why not use it. And by the way the entire earth will thank to those innovative people.

2:56 AM  

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