Thursday, October 14, 2010

Solar Wind Could Power Entire Globe

    Solar Wind Could Power Entire Globe
  • Scientists at Washington State University have designed a satellite that harnesses power from solar wind. A large enough satellite could generate 1 billion billion gigawatts—that's more than 100 billion times the power that humanity needs.
  • Scientists at Washington State University have designed a satellite that harnesses power from solar wind. A large enough satellite could generate 1 billion billion gigawatts—that's more than 100 billion times the power that humanity needs.Here at Smarter Technology, we've recently brought you the latest news in green power sources—everything from harnessing electricity from lightning to synthetic fuels to self-repairing solar cells. Now scientists from Washington State University could make all of these breakthroughs obsolete. A massive solar sail that harnesses the power in solar wind could produce a staggering amount of electricity—100 billion times more energy than humanity needs.

    Washington State University physicists Brooks Harrop and Dirk Schulze-Makuch, whose concept was recently published in the International Journal of Astrobiology, have suggested the use of a solar wind power satellite, which they have named the Dyson-Harrop satellite. In the satellite's design, a copper wire sent into space generates a magnetic field that can capture electrons from solar winds. The electrons are then channeled into a receiver, which produces a current. The wire and receiver could be housed within a circular solar sail.
    In theory, the Dyson-Harrop satellite could harvest colossal amounts of power. Even a relatively small model, New Scientist reports, with a 1-centimeter-wide, 300-meter-long copper wire, could create 1.7 megawatts of power—enough to power about 1,000 homes in the United States. A larger model, with a kilometer-long copper wire, could generate upward of a billion billion gigawatts. Such a massive satellite would require a 5,220-mile-wide sail, but its potential is huge: "… actually 100 billion times the power humanity currently requires," says Harrop.
     

    The energy ability of solar wind lies in its immense speed. Solar electrons—which don't act like wind on Earth—travel through the vacuum of space at several hundred kilometers per second. "It's quite amazing how much power it can actually produce," Schulze-Makuch, told Discovery News.
    While some of the harvested electricity would be used to generate the satellite's magnetic field, most of it would be used to power an infrared laser beam. This laser could transmit energy to stations in space, other satellites and bases on Earth.
    The major issue to consider is how the energy will be transported back to Earth. Since the satellite would be positioned millions of miles from our planet, even the most powerful laser would lose much of its original energy. John Mankins, president of consultancy firm Artemis Innovation, which specializes in space solar power, told New Scientist about these setbacks.
    "Two megawatts spread across areas that large are meaningless, less than moonlight," he said. The satellite "would require stupendously huge optics, such as a virtually perfect lens between maybe 10 to 100 kilometers across," he says. In order for an application to be practical, the Washington State University researchers say, more focused lasers would need to be invented.
    Despite these drawbacks, the use of a solar wind power satellite could be cheaper than other renewable energy options. According to the International Business Times, copper is easier to produce than photovoltaic materials, so this solution would be less expensive than installing an equivalent amount of solar cells into space.
    "This satellite is actually something that we can build, using modern technology and delivery methods," says Harrop.

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