Pentagon offers a ray of hope in energy debate

Out of this world … how the solar power station might look.

Richard Macey
October 17, 2007

THE debate over whether nuclear, solar, wind or clean coal is the energy of the future now has a new player. A report commissioned by an arm of the US Department of Defence has instead proposed lofting power generation into space.

Giant arrays of orbiting solar panels would collect sunlight, which would be beamed via low-power microwaves to massive receivers on the ground, or even directly to customers.

Published by the Pentagon's National Security Space Office, the report says the US should demonstrate the technology by building a pilot "space-based solar power" station, big enough to continuously beam up to 10 megawatts of power to the ground, in the next decade.

A more advanced station, "several kilometres across" and weighing more than 3000 tonnes, could deliver up to 10 gigawatts of electricity. While the report says the project would be a technological challenge, it "requires no fundamental scientific breakthroughs or new physics".

Sunlight's energy in space, where it is not diluted by the atmosphere, is enormous. A kilometre-wide band around Earth receives enough solar energy each year "to nearly equal the amount of energy contained within all known recoverable conventional oil reserves on Earth".

A basic technology demonstrator could be in orbit within six years, while a much bigger one could be operating by 2020, at a total cost of up to $US10 billion ($11.11 billion).

The report claimed the highly efficient microwaves would be significantly less dangerous than the noon-day sun. Microwave leakage at the edge of the rectangular ground antenna would be no more than that of a microwave oven.

In a malfunction "the likelihood of the beam wandering over a city is extremely low, and even if occurring would be extremely anti-climactic. If solar is considered 'green' energy, then [this] could be considered the ultimate green energy."

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URL: clcik here http://www.smh.com.au/news/environment/pentagon-offers-a-ray-of-hope-in-energy-debate/2007/10/16/1192300768027.html

Following my comments on Gundam 00 - Episode 2, could this be the prototype of the space orbit solar power generator?

Now, the proposed power transmission uses microwave?!

And using the extra-terrestrial solar irradiance data from ASHRAE, which is about 1400 W/m2, the article says the station will produce 10 GW of power. That means 10E9(W)/1400(W/m2) = 7.1 million m2/ (or 7.1 km2) of solar panels at 100% efficiency. That is a square of 2.7km x 2.7km!!! 1400 football pitch!!!

Now just what will be the cost, pay back period and the embodied energy of the power plant?

How much will you pay for this kind of electricity?