SOLAR FROM CLOSER TO THE SOURCE

Seems expensive until you stop to consider how much we spend to protect oil supplies in the Middle East. Before this thing in Iraq gets cleaned up, it’s going to be a lot more expensive than sending a few dozen solar satellites into orbit.

Space Solar Energy Has Future, U.S. Researchers Say; Small demonstration project could help justify further research
Andrzej Zwaniecki, August 21, 2007 (U.S. State Department)

WHO
National Aeronautics and Space Administration (NASA) research scientist John Mankins

WHAT
A concept to station mega-satellite photovoltaic arrays with antennas in orbit to convert solar energy into microwaves and beam them to earth.

A megasatellite collector/transmitter. (click to enlarge)

WHEN
In the mid-1990s, a NASA study headed by Mankin envisioned such an energy source to be functioning by 2050. The study described several dozen 2-5 megawatt megasatellites.
Presently, solar cell capacity is much greater and microwave wireless transmission potential has quadrupled, dramatically lowering the costs involved.
September 2006: House of Representatives’ science subcommittee review.
September 2007: Department of Defense feasibility study to be completed.

WHERE
The mega-satellite arrays would be in geostationary orbit. They would send power to locations all over the earth.

WHY
- Sunlight is 8 times less intense on earth’s surface than in extraatomospheric orbit.
- Microwaves efficiently penetrate the atmosphere carrying the converted energy.
- The energy would be received at power stations and applied locally, converted to electricity or used to generate synthetic fuels.
- This form of solar energy would not be intermittent. It would be available at remote, off-grid and disaster (grid-interrupted) sites.
- Martin Hoffert, former chair, Department of Applied Sciences/New York University, has affirmed the validity of this concept in public statements.
- Major obstacle: Transport into orbit via space shuttle costs of $20,000/kg which must come down to $200/kg, making total delivery/robotic assembly costs $3,500/kg. That is still a ways off. Small scale demonstration projects are being considered.

A tower of collectors. (click to enlarge)

QUOTES
Mankin: “[The program] has fallen through the cracks because no organization is responsible for both space programs and energy security…But when you look at the kind of things we as a modern society spend billions of dollars on, [supporting] the idea of limitless clean energy from space is not such a bad goal…”