Japan’s Shimizu Corporation outlined a proposal to build a “Lunar Ring,” a belt of solar panels around the Moon’s equator to beam energy to Earth. The project is framed as a long-term pathway to clean power that could eliminate reliance on fossil fuels.
In its most expansive form, the project could generate up to 13,000 terawatts of energy per hour, a level that would far exceed current global electricity needs if realized at scale. The idea emerged as Japan sought safer energy options after the Fukushima nuclear disaster.
Building on the moon
The plan calls for encircling the Moon’s roughly 11,000 km equator with solar arrays. The arrays would range from a few kilometers to as much as 400 km in width. The goal is to collect sunlight without interruption from clouds, weather, or the day-night cycle. The captured energy would be converted into microwave and laser beams on the lunar surface.
Shimizu proposes transmitting that energy to ground-based receiving stations known as rectennas. This design differs from typical space-based solar concepts focused on orbital platforms. The company says precision pointing, robust safety protocols, and redundancies would be required to send energy across the Earth–Moon distance. Reliability would need to be maintained under variable atmospheric conditions at receiving stations.
The proposal outlines local fabrication on the Moon using in-situ materials. Lunar sand would be processed for concrete. Glass fiber and structural blocks would be manufactured in place to build and support the ring. Construction would be handled primarily by robots under the control of operators on Earth.
Shimizu Corporation’s president, Tetsuji Yoshida, sayid sustained investment in research could develop the necessary technologies to move the Luna Ring from concept to reality. He portrays it as a serious long-term proposal rather than a speculative vision.
The proposal faces clear hurdles. The cost of space-based solar power, including establishing lunar facilities and transporting specialized hardware, is described as staggering. A collision with space debris could cripple a billion-dollar space-based solar power array, according to The Hindu.