Sunday, March 2, 2008

Solar Concentrating Power vs. PV Power

I recently read an article on entitled "The Power of Concentration" which talked about a concentrating solar power (csp) plant that opened a few miles from Las Vegas on February 22, 2008. The article said that the Spanish conglomerate Acciona inaugurated the "Nevada Solar One" plant that is anticipated to generate up to 64 MW, which is capable of powering 14,000 homes. The article also states that "The Solar Energy Industries Association (SEIA) says that more CSP plants, with a total capacity of 4,000MW, are in the pipeline and have signed contracts to sell their future output. An 11MW plant opened in Spain last year (pi. New Energy Finance, a research firm, estimates that 2,000MW of capacity is in the works in Europe."

CSP plants generate electricity by using the sun's radiative heat to boil water, which in turn allows steam to drive steam turbines. To boil water the solar panels focus the sun's light onto one specified location where water will boil. As you might anticipate, this type of technology does not produce any greenhouse gases or pollutants.

However, what I found interesting about this article is the following quote: "And CSP provides a way around the main drawbacks of solar power from photovoltaic cells. Unlike them, it does not involve expensive silicon wafers. And some designs provide power round the clock, not just when the sun is shining, by storing energy in the form of molten salt."

Right now solar power from photovoltaic cells is still relatively expensive, but as the below the below graph demonstrates, PV cell efficiency is increasing at an increasingly linear rate.

Concentrating solar energy into a focal point does not provide much room for advancements within solar energy technology sector. It is a good source of green electricity but I wonder how much electricity it can produce, in comparison to PV cells in the similar layout, during the winter months when the sunlight concentration is lower (just as in the PV case) but also the water temperature is colder. As PV cells are increasing in efficiency, (and as their applications are much broader than desolate desert locations requiring acres and acres of land, such as on top of homes and office buildings) I feel that CSP plants are good clean energy solutions in today's age but are not the best application for using solar energy in the foreseeable future.

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