- Luna Ring offers continuous solar power generation from lunar orbit
- The lunar equator would be home to thousands of kilometers of solar infrastructure
- Power transmission relies on microwave and laser beam systems
A Japanese construction company once proposed wrapping the Moon’s equator in a belt of solar panels stretching nearly 11,000 km.
The Shimizu Corporation, a billion-dollar engineering giant, envisioned a structure ranging from several kilometers to 400 km wide at its widest point.
Assuming an average width of 100 km, the total area would reach about 1.1 million square kilometers, an area roughly comparable to the combined landmass of Texas and California.
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How the Lunar Power Plant Would Work
The concept, called Luna Ring, promised to generate 24 hours of continuous solar power without any interference from weather or atmospheric conditions.
Solar cells that line the lunar equator would convert sunlight into electricity, which would then propagate via a transmission cable to the Earth’s side of the Moon.
There, the energy would be converted into microwave or laser beams and transmitted directly to receiving stations on Earth.
According to Shimizu’s proposal, “the massive energy of the sun will give us a beautiful Earth and an abundant way of life in the future.”
The system would be based on two types of wireless transmission: microwave technology and laser beam technology.
Every country on Earth would have networks of rectennas – antennas that convert microwaves back into direct current electricity – to receive and distribute energy.
But building such an immense infrastructure would require the maximum use of materials found on the Moon itself.
Lunar sand consists of oxide compounds that could be combined with hydrogen brought from Earth to produce oxygen and water.
The same sand could be mixed with cement, ceramics, glass and even solar cells manufactured directly on site.
Large robots would pierce the Moon’s hard inner layer and level the softer ground surface, carrying out most civil engineering work remotely from Earth.
A self-propelled solar cell production factory would move along the lunar equator, manufacturing and installing panels as it goes.
Costs, deadlines and validity remain a vast debate
This discussion has often seemed abstract and struggled to gain the sustained attention needed to move it toward real-world implementation.
When the concept was first introduced in 2010, Tetsuji Yoshida, president of Shimizu’s space consulting subsidiary, acknowledged that it received little attention or public interest at the time.
It was only after the Fukushima nuclear disaster in 2011 that the idea began to gain renewed interest as Japan reassessed its energy strategy.
However, even in 2011, Yoshida admitted that there was still no concrete estimate of the total cost of the project, leaving great uncertainty about its feasibility.
Masanori Komori of the Institute of Energy Economics noted that lunar solar power “sounds good in theory, but costs too much,” and suggested Japan focus on geothermal power instead.
At present, this proposal seems more like a futuristic marketing exercise than a feasible energy solution, for several reasons.
First, building a solar belt longer than the diameter of the Earth in an airless landscape presents staggering engineering challenges.
Second, the robots needed for such construction do not yet exist in operational form, and Shimizu’s glossy brochure appears to underestimate these technical obstacles.
It remains to be seen whether investors will consider this decade-old concept without cost estimates as a true technological roadmap.
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