FORGET conventional solar power – the world’s energy needs could be met 100 billion times over using a satellite to harness the solar wind and beam the energy back to Earth. Focussing the beam could be tricky, though.
The Dyson-Harrop satellite, as the new design is called, orbits the sun far from Earth. On board a long copper wire generates a magnetic field that snags the electrons in the solar wind. The electrons are funnelled into a receiver to produce a current, which generates the wire’s magnetic field to make the system self-sustaining. Any current not needed for the magnetic field powers an infrared laser, which beams energy back to Earth.
A satellite with a 1-kilometre-long copper wire, sitting the same distance from the sun as the Earth, could generate 1 billion billion gigawatts of power, “100 billion times the power humanity currently requires”, says Brooks Harrop of Washington State University in Pullman who designed the satellite (International Journal of Astrobiology, vol 9, p 88).
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“A Dyson-Harrop satellite could generate 100 billion times the power humanity currently needs”
However, to draw significant amounts of power, a Dyson-Harrop satellite needs a constant solar wind that’s only found high above the ecliptic – the plane defined by the Earth’s orbit around the sun. That means the satellite must sit so far from Earth that the laser beam would spread to cover thousands of square kilometres by the time it reached us.
A sharp beam “would require stupendously huge optics”, says John Mankins of in Santa Maria, California. He also points out that the wire could burn out due to the huge current coursing through it. But he does say that a smaller version of this “clever and interesting” satellite could help power some space missions.
