A Japanese firm has come up with the idea of constructing an array of solar cells around the Moon's equator to harvest solar energy and beam it back to Earth. The Shimizu Corporation proposes creating a "Luna Ring" using materials derived from lunar soil along its 11,000-km (6,800-mile) equator. The plan involves starting with an array that's a few kilometers wide and eventually increasing that to around 400 km (250 miles).

The goal is to generate a continuous stream of power from the Moon's lunar equator, which receives a steady amount of exposure to the Sun, and beam it down to Earth from the near side of the Moon. It's an ambitious idea that calls for assembling machinery transported from Earth and using tele-operated robots to do the actual construction on the Moon's surface, once it arrives.

The multi-phase project, to be spread out over a period of 30 years, envisions creating construction materials using a combination of strategies. Water, the firm claims, could be produced by reducing lunar soil with hydrogen imported from Earth. The company also proposes making lunar concrete by extracting cementing material, and utilizing solar-heat treatment processes to create bricks, ceramics, and glass fibers.

The concept also calls for remotely-controlled robots to undertake tasks such as excavating the surroundings, leveling the ground and laying out solar panel-studded concrete. Embedded cables could transfer the collected solar energy and send it to transmission stations that are located on the near side of the Moon.

Power could be beamed to the Earth through microwave power transmission antennas, about 20 m (65 ft) in diameter, and high density lasers, both guided by radio beacons. Microwave power receiving rectennas on Earth, located offshore or in areas with little cloud cover, could convert the received microwave power into DC electricity.

The company claims that its system could beam up to 13,000 terawatts of power around-the-clock. The proposed timeline has actual construction beginning as soon as 2035.

Check out a video on the Luna Ring from Shimizu below.

Source: Shimizu Corporation

Update (Dec 3, 2013): This article originally stated that the project would "generate a continuous stream of power from the side of the Moon that's always facing the Sun, and beam it down to Earth from the side that's in shadow." Our apologies for this error, and our thanks to Gizmag reader David Evans for pointing it out. The error has now been corrected to reflect the fact that there is no such place. Ed.