A few weeks ago, I wrote an article discussing how solar power can be harvested directly from space. This is merely the forefront of countless innovative methods that focus on harnessing solar cells, outside of today’s conventional processes. One overlooked source for solar power is a world we perceive as the sun’s antonym – the Moon.
Due to its lack of an atmosphere, the Moon is constantly bombarded with solar radiation of an amount that’s equivalent to 13,000 terawatts. Leading the charge in efforts aimed at making this concept a reality is retired University of Houston Physicist David Criswell. Using lunar solar power (LSP), Criswell believes it’s not inconceivable to construct a collecting station on the lunar surface that could concentrate and convert sunlight from the moon and wirelessly transfer that energy back to Earth.
“By the year 2050, ten billion people will require at least two kilowatts of electricity per person or a global total of 20 terawatts,” explained Criswell, a figure that’s 70 times the amount of energy output than what was originally projected in models of space-based solar harvesting.
The design of an LSP collector station would be immense, and require several hundred kilometers-worth of solar panels to harness incoming sunlight. The lunar surface contains most of the raw materials to construct an LSP collector’s internal pieces and processors like electric collecting wires, transmission equipment, microwave generators and antennas, along with most support equipment and supplies. The initial system setup could consist of 10 circular collecting bases, each one being about 100 kilometers wide that are built at the edges of the lunar nearside. The collector station would be filled with billboard-sized microwave reflectors that would constantly beam concentrated solar cells down to Earth.
“Each base would output hundreds of separate beams directed toward Earth receivers or via redirectors in a range of Earth orbits,” says Criswell. “An individual beam could then be focused to Earth-based receiving antennas spanning a few hundred meters in diameter.”
Criswell’s model indicates the system would be up to 20 terawatts, and have a projected wholesale price of .001 cents per kilowatt hours of electricity. In retrospect, the average American household pays about .12 cents per kilowatt hour. The power beamed down to Earth could be readily distributed upon reception. To extenuate these conditions, the orbital system between the Earth and Moon could eventually be “electrified” according to Spacefaring Institute President Mike Sneak. This would be done so electrical power could be distributed over broader wavelengths like microwave, terahertz, and lasers.
“A power station on the Moon would deliver roughly 200 gigawatts to a single location on Earth,” adds John Mankins, President of Mankins Space Technology. “There are no markets that need that amount of power in a single large ‘chunk’.”