Thursday, April 16, 2009

Problems with Space Based Power

Solaren which recently signed an agreement with PG&E to purchase power in 2017 is an upstart company with an address in Manhattan Beach, California. Their plans for space based power generation are certainly not finalized and they are still looking for a site for their facility.

The power levels that they are looking at are 200 megawatts with a receiving station covering a few square miles. Let's say 4 square miles or 10 million square meters. This would imply an energy density of about 20 watt per square meter of surface area. It will be a little higher perpendicular to the direction of the beam since it strikes the surface at an angle. By comparison the solar constant is 1,366 watts per square meter. They will probably claim that the power transfer is point to point rather than being broadcast but can they guarantee confinement of the beam to their property and not expose the public to risk on nearby highways and byways?

That raises the question of the right of free passage and who has the right of way. Will the facility create a hazard to navigation? Not just in the air but also in space? A space based facility may need international approval. It is not just the company's decision or California's decision. International boundaries are crossed and so the federal government will have to be involved.

With respect to geosynchronous orbit there may be no construction code in effect but the launches need to be approved. And there are concerns about geosynchronous orbit becoming overcrowded. So it is still a waiting game to see what happens.

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