Japan’s Space-based Solar Power Plant

The Japan Aerospace Exploration Agency, also known as JAXA, took a big step forward after successfully transmitting electricity wirelessly through microwaves in an experiment conducted at the Mitsubishi Electric Corp. outdoor testing ground at Hyogo Prefecture on March 8, 2015

JAXA managed to convert 1.8 kilowatts of electrical power into microwaves and proceeded to transmit them into an antenna at the receiving end over a distance of approximately 55 meters. Kazuo Ohashu, JAXA’s Advanced Mission Research Group director, said, “Being able to control microwaves is an important technology in transmitting electricity safely and without loss. “The successful test was a big step for us.”

The experiment is part of the Space Solar Power Systems (SSPS) project, wherein sunlight is collected in a geostationary orbit. The generated energy is then converted into microwaves, which are transmitted back on Earth and transformed into electricity and hydrogen.

With the use of a space-based solar power plant, unlike solar panels on Earth, energy would be collected from the Sun continuously, unaffected by weather concerns or darkness. In addition, according to Yasuyuki Fukumuro from the Research and Planning department, SSPS technology is very friendly to the environment because the energy is generated from the Sun in space and since carbon dioxide is only emitted at the receiving site, emissions of carbon dioxide within the atmosphere of the Earth can be significantly reduced.

Probably one safety concern in this is that individuals on Earth may be exposed to microwave beams if they are misaligned with the receiving end on the ground. It is not yet fully known what the effects of this would be, thus the alignment must be strictly accurate. In case the event does happen, precautionary measures on the receiving site will be taken and transmissions will be immediately stopped.

Space Solar Power Systems has just moved to its technological demonstration phase, and if the project is realized, the converted energy will be transmitted from an altitude of 36,000 kilometers to a flat surface that is 3 kilometers in diameter. Fukumuro is positive that Japan currently has the technological capacity to control the direction of the microwaves and transmit them with precision from a geostationary orbit in space to a receiving base on the ground. Researchers are hopeful for the practical use of space-based solar power generation by the year 2030.