Japan plans to send solar energy from space to Earth in the upcoming year, exactly two years after American engineers accomplished a similar task. As the fight against climate change intensifies, this breakthrough represents a significant step toward the potential building of a space-based solar power plant that might aid in the global transition away from fossil fuels.
Adviser at Japan Space Systems, Koichi Ijichi outlined Japan’s path toward an orbital demonstration of a small space-based solar power plant that will wirelessly transmit energy from low Earth orbit to Earth during his speech at this week’s International Conference on Energy from Space.
“It will be a small satellite, about 180 kilograms [400 pounds], that will transmit about 1 kilowatt of power from the altitude of 400 kilometers [250 miles],” Ijichi stated during the press conference.
Depending on its size, a household appliance like a small dishwasher can run for approximately an hour on one kilowatt of power. As a result, the demonstration is far from the size needed for commercial application.
A battery will be charged by the spaceship using an onboard photovoltaic panel measuring 22 square feet (2 square meters). After that, the stored energy will be converted to microwaves and directed toward an Earthly receiving antenna. The spaceship travels at a high speed of 17,400 mph (28,000 km/h), therefore in order to transmit enough energy, the antenna elements will need to be spaced 3 miles (5 km) apart over a distance of around 25 miles (40 km).
Ijichi stated, “The transmission will only take a few minutes.” “But once the battery is empty, it will take several days to recharge.”
As a component of the OHISAMA project, which translates to “sun” in Japanese, the mission is scheduled to launch in 2025. In December, the researchers hope to transmit solar electricity wirelessly from an aircraft, having already shown how to do so with a stationary source on the ground. According to Ijichi, the airplane will be outfitted with a photovoltaic panel that is exactly the same as that which will be flown on the spacecraft. This panel will be able to beam down power over a distance of 3 to 4 miles (5 to 7 km).
From Idea to Actuality
Space-based solar power generation was initially reported by a former Apollo engineer in 1968.
Science fiction has been applied to Peter Glaser. Though technically possible, the technique has been viewed as excessively expensive and impractical because it has to assemble massive structures in orbit in order to provide the necessary power output.
But as a result of recent technology advancements and the pressing need to decarbonize the global power supply in order to halt climate change, the experts speaking at the conference say that the situation has changed.
Space-based solar energy has the potential to be continuously available, unlike other renewable power generating methods utilized on Earth, such as solar and wind energy, since it is not dependent on the weather or the time of day. At the moment, demand is met by nuclear power facilities or gas- and coal-fired power plants after dusk or when the wind stops. Future technological advancements can contribute to a partial solution of the issue. However, as specified in international climate change agreements, certain pieces of the puzzle need to be completed before the middle of this century to ensure a seamless supply of carbon-neutral power.
According to the experts at the conference, advancements in robotic technology, increases in wireless power transmission efficiency, and—above all—the advent of SpaceX’s massive rocket Starship might make space-based solar power a reality.
Solar power was first beaming from space last year thanks to a satellite developed by Caltech engineers as part of the Space Solar Power Demonstrator program. The operation was hailed as a significant accomplishment when it ended in January.
There are now numerous more space-based solar power demonstration projects under development. International space and research institutions, such as the European Space Agency, the Defense Advanced Research Projects Agency, and the U.S. Air Force, are studying the technology. Startups and commercial businesses are also creating concepts, utilizing Starship’s accessibility and the development of sophisticated space robotics.
On the other hand, not everyone is excited about space-based solar power’s possibilities. NASA published a report in January that cast doubt on the technology’s viability. The energy produced by orbital power plants would be excessively costly due to the difficulties and energy needed to construct, launch, and assemble them; as opposed to as little as 5 cents per kilowatt-hour for Earth-based solar or wind energy.
