Thursday, 15 September 2011

Solar power and space elevators revisited...

About 18 months ago, I posted about how we could use space elevators to harness solar energy. (Jim Bliss added some ideas and suggested a book for me to read - more about that later)

Now there's a company with a similar but much more practical idea.

You see, to get into space needs a lot of technical stuff. Some really heavy duty engineering. And what you're getting is subject to the law of diminishing returns.

What I mean by this is that if you collect solar energy from 12 miles above the Earth's surface, you're above 95% of the atmosphere. Going another hundred miles up doesn't gain you much, but adds enormously to the cost and complexity of your operation.

What is being proposed is that optics are attached to a sort of hydrogen balloon, which is connected to the ground using a pipe that conducts the collected light down to the ground, where it is used to heat stuff up, rather like using a magnifying glass to burn holes in black trousers.

Personally, I think this is a great idea. The science is straightforward and well understood. The power plants have a very small footprint compared to more conventional solar power generation, and can easily be placed close to where they are needed. the hydrogen required to make the things float can be obtained using some of the power they generate.

There are risks too of course. The pipes that conduct the light to ground have to be large. Weather, Ice, high winds, Aircraft, terrorists. All would pose a threat.

A variation on the theme is to put photovoltaic panels 12 miles up and send the energy down a much smaller pipe as electicity instead. This would potentially be a much better way of using PV in high latitudes.

Thank you to The Oil Drum for the article.

It even contains some rather fetching google earth representations of how such a power plant might look. Clearly  company after my own heart.

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