Japan’s Plan to Supply all the World’s Energy

Shimizu, a Japanese architectural and engineering firm, has a solution for the climate crisis: Simply build a band of solar panels 400 kilometers (249 miles) wide (pdf) running all the way around the Moon’s 11,000-kilometer (6,835 mile) equator and  beam the carbon-free energy back to Earth in the form of microwaves, which are converted into electricity at ground stations.

That means mining construction materials on the Moon and setting up factories to make the solar panels.

“Robots will perform various tasks on the lunar surface, including ground leveling and excavation of hard bottom strata,” according to Shimizu, which is known for a series of  far-fetched “dream projects” including pyramid cities and a space hotel.

The company proposes to start building the Luna Ring in 2035.

“Machines and equipment from the Earth will be assembled in space and landed on the lunar surface for installation,” says the proposal.

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If  that sounds like a sci-fi fantasy—and fantastically expensive—it’s not completely crazy. 

California regulators, for instance, in 2009 approved a contract that utility Pacific Gas & Electric signed to buy 200 megawatts of electricity from an orbiting solar power plant to be built by a Los Angeles area startup called Solaren.  

The space-based photovoltaic farm would consist of a kilometer-wide inflatable Mylar mirror that would concentrate the sun’s rays on a smaller mirror, which would in turn focus the sunlight on to  high-efficiency solar panels. 
These would generate electricity, which  would be converted into radio frequency waves, transmitted to a giant  ground station near Fresno, California, and then converted back into  electricity.

Unlike terrestrial solar power plants, orbiting solar panels can generate energy around the clock. The part-time nature of earthbound solar power means it can’t currently supply the minimum or “baseload” demand without backup from fossil-fuel plants. 

However, the cost of lifting the solar  panels into orbit would be far higher than for building a photovoltaic  power plant on earth.

Not  much has been heard from Solaren since then, but last year Michael  Peevey, president of the California Public Utilities Commission, said in  a speech that the project was still under development. 

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“Although this  sounds like science fiction, I am hopeful that recent advances in  thinner, lighter-weight solar modules will make this technology  feasible,” Peevey said. “I believe it is worth taking a chance on this  technology because as a baseload resource, space-based solar may help to  displace coal-fired capacity that would otherwise meet those needs.”

But even  if the energy that eventually comes from a solar power plant on the the Moon justifies the costs of building one—not to mention the fossil fuel you have to burn to get the machinery up there—Shimizu’s greatest  hurdle may be staking a claim on all that lunar real estate, points out Wired. 

“Outer space law is notoriously difficult to apply in practice and may scupper the plans long before anything gets built.”