The key to our energy future may be in space. A new long-range energy transmission experiment opens the possibility of sending solar energy from space to earth.
A former NASA scientist has used radio waves to transmit solar power a distance of 148 km between two Hawaiian islands, an achievement that he says proves the technology exists to beam solar power from satellites back to Earth.
John C Mankins demonstrated the solar power transmission for the Discovery Channel , which paid for the four month experiment. His vision is to transmit solar power collected by orbiting satellites as large as 500 kg to lake-sized receiver stations on Earth.
Mankins, who worked at Nasa for 25 years and managed the agency’s space-based solar programme before it was disbanded, transmitted 20 watts of power between the two islands in May. The receivers, however, were so small that less than one one-thousandth of a percent of the power was received, Mankins said. The experiment cost about $1 million, and Mankins said larger arrays could be constructed with more money.
Each of the nine solar panels used was built to transmit about 20 watts of power, but the transmission was scaled back to two watts per panel in order to obtain US Federal Aviation Administration approval for the test.
Although the amount of power sent is barely enough to power a small compact fluorescent light bulb, and most of it was lost in transmission, the system was limited by the budget not the physics.
If they had been able to afford more solar panels, more phased array transmitters and a better receivers (the one they had could only receive in the horizontal direction), Mankins claims they could do much better – possibly up to 64% efficiency. “The test was in no way fully successful,” he said. “I think it showed it is possible to transmit solar power quickly and affordably.”