Space Solar Panels Would Beam Energy Back to Earth

Scientists believe clean energy will eventually come from solar panels in space.
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Scientists believe clean energy will eventually come from solar panels in space.
space solar panels

Photo Credit: U.S. Navy

As the need for clean energy grows, some scientists believe we will soon be getting our energy from solar panels in outer space. The energy would be continuous, unlimited and clean. The idea is to place the solar panels within Earth's orbit, about 22,000 miles up.

"If you put the solar panel in space, it's going to be illuminated 24 hours a day, seven days a week, 99% of the year," Paul Jaffe, a spacecraft engineer at the U.S. Naval Research Laboratory, told Business Insider. He adds that because the Earth's axis of rotation is tilted, "even on the night side of the Earth [the satellite could] be in sunlight almost all the time."

Jaffe says the amount of energy that could be collected from the sun using this method "is effectively infinite."

Solar panels work by collecting photons sent out by the sun into electrons. The biggest obstacle of having a solar farm in space is transferring the current from the reflectors to earth. The current answer is to use electromagnetic waves.

"People might not associate radio waves with carrying energy because they think of them for communications, like radio, TV, or cellphones. They don't think about them as carrying usable amounts of power," Jaffe said.

Jaffe calls the project he is working on the "sandwich" module. The top of the sandwich will receive the solar energy and antennas at the bottom will bean the radio waves to Earth. The whole module would be about 10 feet long, and about 80,000 of them would be needed.

An antenna called a rectenna would receive the energy on Earth. It could end up being about six miles in diameter.

"It would look like a field full of wires sticking up. The rectenna elements receive incoming radio waves and convert it back from that high frequency radio wave into electricity," Jaffe said.

The radio waves could be sent to many locations on Earth -- retrodirective beam steering can be used to change the direction of the beam.

"This works by sending up a small 'pilot signal' from the center of the ground receiving station. The satellite sees this signal and adjusts its transmitter to send the radio waves to the ground station," Jaffe said. So, the same beam would be able to provide power to several countries.

The biggest obstacle of creating a solar farm in Earth's orbit is cost. It is unknown exactly how much this project would cost, but it would be hundreds of millions of dollars. The components would be too large to launch into space, and strapping them to rockets is an extremely expensive endeavor. The farm would have to be built part by part with this method. 

space solar panels

Photo Credit: U.S. Navy