Thursday, 29 May 2008

Why There Isn't More Solar Power

It costs too much, it happens at the wrong time, and the panels are made of the wrong stuff. But there's good news on the horizon.

When you can get coal electricity for 1.2c, why would you pay 25c for solar power? That's why China built 600 massive coal power stations in 2006, and why huge amounts of power in Australia, England and America comes from coal. It's also a reason why those countries are leery about the Kyoto Protocol. (China has coalmines which have been burning like tyre fires for decades, polluting more than all the vehicles in America put together, and no-one knows how to put them out. Except maybe use all the coal that's safe to mine.)
There's also the problem of delivery. Solar only makes power when the sun is out, but people's power usage spikes from 6-10pm. Power companies don't need power at midday, and so they pay less for it at that time. The power can be stored in battery banks, but that adds even more to the cost and reduces the total because of conversion losses.
If that weren't enough, the chief element of solar panels, silicon, is in short supply. The world can produce enough silicon each decade to power about 50 million houses in a First World country--and that's if everyone halted all production of computers and cars, the two main consumers of silicon.

But this year, a product from the Palo Alto Research Center (the guys who came up with the computer mouse, laser printers, and the internet) has shifted the goalposts.
Cruel schoolboys have always found ways of turning science to their own evil purposes. The concentrated rays of the sun will fry an ant in seconds, and it is precisely this principle which PARC have used. By using plastic lenses in a fresnel pattern--like those uses in stage spotlights--they have cut the amount of silicon needed to 1/500th of a regular panel. At one stroke, the cost of solar panels is reduced by orders of magnitude. The scattered rays of the sun are focused in tight beams on small squares of silicon, delivering twice the energy of similarly-sized panels despite the massively reduced collector surfaces.

The only problem with the new panels is the heat concentrated on small areas. IBM have solved this problem in one way by using computer processor's heatsinks to draw away heat with copper and other materials, dispersing it with long spines. Other, smaller companies have used the heat to generate further electricity using a Stirling engine, which runs on heat. In this way, their products utilize the sun's energy twice over.

For a long time there have been few options to create the power we use; often a choice between the unpalatable and the disastrous (as Galbraith said of politics). There has developed, over the last few decades, a clear mandate for renewable sources of energy, but finding a strong candidate was difficult. Breakthroughs like the products from PARC and IBM overcome the stumbling blocks of power generation we know to be inevitable. Their efforts mean that we can implement widespread changes sooner, rather than doling out this public good--clean power--slowly and grudgingly.

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