One of the aspirations of the Japanese Space Agency (JAXA) is to be able to provide energy to its country without depending on imports from other countries, especially since the Fukushima catastrophe and the step backwards that occurred regarding the use of nuclear energy for the electric power generation.
One of the proposals they are working on is a solar farm in space. There, solar energy would be captured very efficiently and sent to Earth. A cable linking those panels to Japan is not an option right now, so the work of JAXA and Mitsubishi is now focused on wireless power transmission from space.
The challenge is both power and precision
These days several tests have been carried out to advance the great challenge of the solar farm system that Japan wants to develop: the transmission of energy to the Earth. The process requires overcoming two major challenges.
The first is the power to transmit. Mitsubishi has completed these days sending 10 KW of energy over a distance of almost half a kilometer with an efficiency that has not been disclosed. For now, the energy conversion systems maintain 80% efficiency, but the problem will be in the losses due to distance.
If this last data were much less, it would not make sense to invest in an installation of this type. Currently, the first tests leave a loss of more than 75% of power in a distance of 50 meters. Mitsubishi is testing the technology to be able to apply it in a first phase in the wireless charging of vehicles.
The other hurdle to overcome when thinking about more advanced phases of the future solar farm is precision. It will not be enough to send large amounts of energy wirelessly, but the destination will be a very specific area for safety and efficiency. And the JAXA test these days has been a huge success. The Japanese agency has managed to successfully send 1.8 KW of energy (never done with such an amount) at a distance of 50 meters using microwaves, hitting a single antenna and with very precise control of the direction of the waves.
The phases of the Japanese solar farm project
The Japanese solar farm project consists of several satellites orbiting about 35,000 kilometers from Earth, with an area of several kilometers. The project's roadmap spans 25 years, with a first test satellite to be launched into space in 2018. That first satellite will operate in a low orbit and will be responsible for sending small amounts of energy (a few KW) to a receiving station. microwave waves on Earth. By 2021 the plan is to have a satellite with the capacity to send up to 100 KW of energy to Japan, reaching 200 MW in 2028. The culmination of the plan will arrive at the earliest in 2031, when the first solar energy generation pilot program since space is capable of generating 1 GW. In 2037 JAXA could launch its system commercially.