Is 'Luna Ring' the Energy Solution or Looney Pipe Dream?

TOKYO, July 12, 2011— -- When Tetsuji Yoshida first unveiled a revolutionary plan to generate solar energy on the moon last year, the news received little fanfare. Yoshida envisioned a "lunar ring" or belt made up of solar panels placed around the moon's equator that could power all of planet Earth.

The president of space consulting group CSP Japan, a subsidiary of Japanese construction firm Shimizu Corporation, says his plan was featured on NASA's Lunar Science Institute website. But it didn't generate much interest beyond that.

That is, until March 11, when a massive earthquake and tsunami crippled nuclear reactors at the Fukushima Daichi Power Plant, raising serious questions about the country's energy policy.

Japan's 54 nuclear reactors generate 30 percent of the nation's energy supply, but with more than half of them idle because of safety concerns, the Japanese are looking to alternative forms of energy to power the country. And lunar solar power is emerging as a potential source.

"It's been very quiet for about a year, so it's surprising to get this attention, one year later," Yoshida said.

Scientists have looked to space as a gold mine for clean energy for decades. Yoshida says American scientist Peter Glaser first proposed placing solar panels in space back in 1968, and NASA began research on it a decade later.

Lunar Ring and Solarbird Are Latest Efforts to Generate Power From Space

The moon is seen as prime location for solar energy because there is virtually no atmosphere, meaning no bad weather or clouds to keep the sun's rays from the panels. Even in the most ideal situations, Yoshida says solar panels on Earth can only generate one-twentieth of the energy produced in outer space.

"In space, there is constant light hitting the solar panels," he said. "When all the energy created from those panels reaches Earth, there will be no need to produce energy from coal, oil, or biomass."

The Luna Ring proposed by Yoshida, on behalf Shimizu Corporation, attempts to harness solar energy on a larger scale than previous concepts. It involves building a belt of solar panels around the moon's 6,800 mile equator, and using built-in cables to transmit the power generated by the solar cells, to the near side of the moon – the side, facing the Earth. The electricity would be converted into microwaves and lasers beamed at Earth, and each country would have receivers that allow them to take in the energy and store it.

Yoshida says the project would largely rely on robots to build the infrastructure, while a team of astronauts would support the machines on-site. Construction could get underway by 2035, if Shimizu Corporation gets the proper funding.

Shimizu is the latest in a growing number of Japanese organizations looking to generate solar energy in outer space. Earlier this year, the Japan Aerospace Exploration Agency, Mitsubishi Electric Corp, and Kyoto University announced they would jointly conduct solar power generation research. The hope is to launch a trial satellite system that generates solar power in the next decade. Separately, Mitsubishi Electric has proposed the Solarbird project, which would use dozens of solar power generating satellites to produce the amount of energy equal to a nuclear power plant.

Masanori Komori with the Institute of Energy Economics says solar energy generated in outer space sounds good in theory, but costs too much. He says Japan should be looking at more realistic forms of alternative energy, like geothermal power.

"The problem with lunar solar energy is that it's still in the research phase," Komori said. "We need to first focus on what we can get now."

Yoshida admits he doesn't have a concrete estimate on the cost of the Luna Ring, or an exact time frame on how long construction would take. But he has no doubts about its potential for alternative energy.

"All we are doing is using existing resources. We have sunlight, we have solar panels, and we already have microwaves and laser beams," Yoshida said. "If we can continue to do the research, we think there's a huge chance this could become reality."