Wireless power transmission technologies for solar power satellite

Solar Power Satellite (SPS) is an energy system which collects solar energy in space and transmits it to the ground. It has been believed as a promising infrastructure to resolve global environmental and energy problems for human beings. One of the most important technologies for the SPS is the wireless power transmission from the geostationary orbit to the ground. Microwave power transmission has been investigated and demonstrated for more than 40 years, but still requires further research regarding high-efficiency power conversion and high-accuracy beam control for SPS application. This paper introduces the concept of SPS, and presents microwave power transmission technologies necessary for SPS, their demonstration experiments both on the ground and in space in the near future, and future prospects towards commercial SPS.