Beaming electricity from space to Earth

J-STORIES ー The Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Japan Aerospace Exploration Agency (JAXA) will start an experiment next fiscal year by deploying solar panels in space with the aim of realizing "space solar power.” Solar energy is collected in space, electricity is generated, and then sent to the ground for use as power.

“Space-based solar power” is the collection of solar energy in space, which is used to generate electricity that is then sent to the ground. In the coming fiscal year, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Japan Aerospace Exploration Agency (JAXA) will deploy solar panels in space and begin demonstration tests.

The Japanese government has set a goal of carbon neutrality by 2050, in which greenhouse gas emissions and their absorption are balanced to achieve virtually zero net emissions. Space-based solar power is seen as an effective way to achieve that goal. The Japanese government’s Space Development Strategy Headquarters confirmed its policy at the end of June last year, saying, “We must strengthen efforts toward the practical application of space solar power generation.”

The new HTV-X will be capable of transporting devices that require power supply and enhance cargo services.     Source: JAXA website — The new HTV-X will be capable of transporting devices that require power supply and enhance cargo services. Source: JAXA website

According to JAXA, the new HTV-X1 space station supply vehicle, which is scheduled to be launched next fiscal year, will carry solar panels into geostationary satellite orbit for demonstration tests.

The development of space-based solar power has stalled in many countries due to high cost and difficulties with the technology. But Japan has continued its efforts and is at the vanguard of global research.

The technology, however, is a long way from practical application. Electricity generated by solar energy is transmitted from space to earth as microwaves and turned back into electricity, but the technical barriers to long-distance microwave transmission are still high. There are huge costs that cannot be avoided, including the cost of transporting massive solar panels and building large space structures.

Daisuke Jodoi of JAXA researches the construction of large space structures for space solar power systems (SSPS). He told J-Stories that, “There are still many hurdles to overcome before the implementation of SSPS, but this demonstration is the first step and we will steadily continue our research.”

The SSPS emits no greenhouse gases or hazardous waste. Yet, costs related to transportation, maintenance and safety concerns remain issues.     Source: JAXA website — The SSPS emits no greenhouse gases or hazardous waste. Yet, costs related to transportation, maintenance and safety concerns remain issues. Source: JAXA website

Daisuke Jodoi of JAXA, who is researching the construction of a large space structure for the Space Solar Power System (SSPS), told J-Stories, "There are still many hurdles to overcome before the SSPS can be realized, but we would like to take this demonstration as a first step and steadily proceed with research and development."

Since microwave transmission technology is expected to be used not only for space solar power generation but also for a wide range of other industrial applications, and the international competition for practical use is becoming increasingly fierce, with the United States and China stepping up their development.