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#1 Solar Wind Power
Posted: Fri Oct 01, 2010 5:35 pm
by rhoenix
Popular Science wrote:Never mind using the solar wind to power spacecraft — that’s old hat. Scientists at Washington State University want to use solar wind to power the entire world. A humongous solar sail could be used to harvest the power of solar winds, generating 1 billion billion gigawatts of electricity. The problem is figuring out how to get the power back to Earth.
A solar wind power satellite, or a Dyson-Harrop satellite, after the scientists who invented it, would provide 100 billion times as much power as the Earth currently uses, as Discovery News points out. Researchers from Washington State University published a paper describing the system in the International Journal of Astrobiology.
It involves a .4-inch-wide copper wire pointed at the sun, and attached to a solar sail. The wire — which can range in length from 980 feet to more than half a mile — would generate a magnetic field that would capture electrons from the solar wind. The particles would be funneled into a spherical receiver, which produces a current.
Some of this electricity would be used to power the electron-harvesting magnetic field. The rest would power an infrared laser beam, which would be pointed at collectors on space stations, power bases or Earth. Satellites could be placed anywhere in the solar system, and networks of satellites could combine to generate terawatts of power, the researchers say.
The system would be cheaper than installing solar panels in space, because copper is cheaper than photovoltaic cells, according to International Business Times.
The main problem is getting all this energy back to the planet. Satellites would have to sail tens of millions of miles away from Earth in order to capture enough power, but even the most powerful laser beams would scatter over such great distances. The laser would spread to thousands of miles wide, according to John Mankins, president of solar power consulting firm Artemis Innovation. He is quoted in New Scientist saying you would need "stupendously huge optics, such as a virtually perfect lens between maybe 10 to 100 kilometers (6.2 to 62 miles) across," to capture the laser.
Researchers would have to design a more focused laser before solar wind satellites could be deployed, acknowledges to Dirk Schulze-Makuch, a co-author of the paper.
Still, the idea seems worth exploring — the solar wind is a vast source of energy, so why not try to capture some of it? If it could solve the world’s energy problems for good, it's worth a closer look.
Well, the engineering issues of making a perfect lens 100km in diameter aside, this does sound like a good idea to me. With the amount of potential power here, it could become a large supplement to any nation's energy supply.
#2
Posted: Fri Oct 01, 2010 7:27 pm
by frigidmagi
How about a bunch of smaller lens? Say an orbiting fleet of them? I imagine we would get less energy overall but do we really need
1 billion billion gigawatts of electricity
?
#3
Posted: Fri Oct 01, 2010 7:53 pm
by rhoenix
frigidmagi wrote:How about a bunch of smaller lens? Say an orbiting fleet of them? I imagine we would get less energy overall but do we really need
1 billion billion gigawatts of electricity
?
Now? No.
However, given the way the world's energy needs are accelerating due to developing nations edging closer to joining the First World nations in terms of power consumption, I suspect it might be necessary within a century.
Given world politics, I don't see this being a multi-nation project - however, your other point is a good one. A single nation doesn't need a solar wind sail that large, unless there's a severe cutoff of size versus efficacy.
#4
Posted: Fri Oct 01, 2010 8:37 pm
by frigidmagi
Even if all the 3rd world jumped to our power usage it wouldn't be a 100 billions time more then currently being used. I'm not against the idea but it seems a number of smaller ones would be easier to make and deploy and still provide all the power we need. Plus if we end up needing more power... Just make more sails. Easier.
#5
Posted: Fri Oct 01, 2010 8:52 pm
by rhoenix
frigidmagi wrote:Even if all the 3rd world jumped to our power usage it wouldn't be a 100 billions time more then currently being used. I'm not against the idea but it seems a number of smaller ones would be easier to make and deploy and still provide all the power we need. Plus if we end up needing more power... Just make more sails. Easier.
It would be far more cost-effective as well, I imagine.
I was thinking of your point, about how it would be much more economical to use the same thing at a smaller scale instead of at the scale described by the article. Man, I've got nothing - one shouldn't just make something huge just because one can.
#6
Posted: Fri Oct 01, 2010 9:38 pm
by Destructionator XV
The problem seems to be that you have to move quite a bit away from Earth to gather this stuff, so a small laser would be even worse off than a big one; it has less energy to space to distance losses.
This sentence from the article bugs me though:
"The system would be cheaper than installing solar panels in space, because copper is cheaper than photovoltaic cells, according to International Business Times. "
The big cost for space solar panels isn't the panels themselves - it is getting them up there in the first place. This beastly thing would have the same problem.
The idea sounds cool, but there's a lot of difficulties involved, and it needs all new technology developed. Regular solar panels (or solar thermal generating stations) are already a pretty mature technology, so with them, instead of two problems (building the thing and launching the thing) we are left with just one (launching them).
The oldie seems like the safer bet.