06 March 2008

Solar Thermal: The More Mature Older Solar Sister

Of the "Solar sisters", PV and Thermal, Thermal is clearly the more mature and ready for primetime. Why? Because Thermal solar contains its own storage.
...Some of the new plants will feature systems that allow them to store heat and generate electricity for hours after sunset..

..The workability of solar thermal power was established in the 1980s, when developers in California built a series of plants in the Mojave Desert, eventually reaching 354 megawatts of capacity. A megawatt is enough electricity to run 1,000 room air-conditioners at once.

The California plants grew more sophisticated and costs shrank as the project progressed. But then the price of a competing fuel, natural gas, collapsed in the 1990s and building new solar plants became uneconomic.

...solar plants do tend to produce peak power during the hottest part of the day, when demand is highest and electricity is costly, so at certain times they are already competitive with plants using natural gas. And they have an advantage over the other widely available form of renewable power, wind turbines: they are more predictable.___NYTimes__via_KurzweilAI.net

Heat is currently easier to store for later use than is electricity. With photovoltaic, when the sun is gone the power is gone. With solar thermal, the heat can be stored and used for several hours after sundown, until people go to bed.

Al Fin has argued for the superiority of solar thermal over PV for years. Incorporating phase change materials in thermal storage systems should extend heat storage through most of the night.


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Blogger Snake Oil Baron said...

Where do concentrating PVs fit? If they are slightly more efficient than the thermal concentrators it would probably make sense to have a fraction of a solar field dedicated to the concentrator PVs and the larger fraction dedicated to thermal so that the peak demand efficiency and the storage potential are balanced.

Thursday, 06 March, 2008  
Blogger al fin said...

Solar concentrators combined with efficient PV can be very efficient, although usually expensive.

Solar energy comes in a spectrum, from ultraviolet to infrared. The more of that spectrum that you can use, the more efficient your process will be.

There is a place in the total scheme of things for every conceivable energy generation and storage scheme--even hydrogen (if nano-storage works out).

When trying to build a large solar facility to compete with coal or nuclear, you have to look at economic efficiency, building cost, operating cost, and integration into the grid. Can the power be used as baseload power for enough time to make it reliable?

Solar thermal can integrate into the grid better due to the "flywheel effect" of thermal energy, which can be stored and persists beyond sunset for generating electricity. Concentrators (shaped, aimed mirrors) are used for solar thermal, just as concentrating lenses can be used for PV

Friday, 07 March, 2008  

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