The idea of collecting solar energy from space and sending it down to earth is an old one. It was first conceptualized by an American physicist back in 1968. The US government even invested shortly in the idea around 1970 amidst the fuel crises. After that it lost steam. Since the 1980s, Japan has been making some serious strides toward the realization of the near-science fiction idea of space-based solar power.
In 2009, a team under the leadership of professor Naoki Shinohara, successfully sent energy to a phone on the ground from 30 meters above. In 2015, they were successful in beaming 1.8 kilowatt of power to a receptor over 50 meters away horizontally. They ran the same experiment successfully in 2018 again, but this time vertically.
JAXA, the space administrator in Japan, is seeing some serious potential in the idea of space-based solar power and the strides made towards it. A public-private-academic project led by Naoki Shinohara has its eyes on sending solar arrays to orbit by 2025.
Why all the fuss about space-based solar power? One, once the solar arrays are in space, they can collect solar energy regardless of the time of the day – it is a potentially infinite source of renewable energy. Two, since the arrays will use microwaves to beam the power down to receivers on earth, the clouds won’t make a difference. Yes, they’ll use the same type of electro-magnetic radiation used in a microwave oven.
Once the receivers receive the power beamed down from the space-bound solar arrays, the energy will be converted into electrical power.
The current goal set by the Japanese project is to send a bunch of solar arrays to space by 2025. However, there are a lot of technological hurdles to cross before we can practically use space-based solar energy. In order to produce one gigawatt of energy – equivalent to the amount produced by a nuclear reactor – we’ll need solar panels covering an area of 2 square kilometers. Delivering and setting up such quantities of solar arrays in space will cost around $7.1 billion with our current level of technology. Hopefully, this will become practical at one point of technological evolution.