Disclaimer. After nearly 40 years managing money for some of the largest life offices and investment managers in the world, I think I have something to offer. These days I'm retired, and I can't by law give you advice. While I do make mistakes, I try hard to do my analysis thoroughly, and to make sure my data are correct (old habits die hard!) Also, don't ask me why I called it "Volewica". It's too late, now.

BTW, clicking on most charts will produce the original-sized, i.e., bigger version.

Thursday, June 12, 2014

Solar Towers

Solar panels (photovoltaic cells) are not the only way to convert sunshine to electricity.

This article talks about the largest concentrated solar power (CSP) project in the world.  In essence, it consists of heliostatic mirrors which "follow the sun" (like sunflowers), reflecting the heat and light to a central focus.  At that central point, the heat is intense enough to melt salt, which is then used to produce steam which runs a turbine generator.  The key advantage of this is that the heat can be stored and released later, when there is no sunlight.   Another advantage is the CSP uses the whole spectrum of sunlight, i.e., including heat (infra-red) whereas PV cells (solar panels) just uses visible light.

The chart below shows how this would work.  The blue line represents a PV cell.  Note how it rises smoothly towards its maximum (a quartic by the looks of it, I thought it would be like a normal distribution!):  the spikes from 10 o'clock onwards are due to clouds.  The green line shows the concentrated solar power output when it releases its electricity over 8 hours into the grid, starting at midday.  The yellow line is the same thing over 16 hours.

This technique enables solar to be used as baseload power.  In effect, in places where the sun shine strongly and a lot, houses/shops/factories would have their own solar panels for daytime use and would use CSP for the evening and the night. No need for gas or coal or nuclear.  As the article mentions, there are some places where CSP is already producing power, without subsidies, at 13.5 cents per kWh (the average retail electricity price in the US is about 12.3 cents, in Australia it's about 28 cents).  For Australia, Spain, SW USA, southern China, India, etc, this alternative form of solar is likely to very soon make not just new coal plants but also existing coal plants too expensive.

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