A team of reserachers led by Washington University in St. Louis has carried out a study that compares photosynthesis and photovoltaics, and finds that photovoltaics are the more efficient of the two (though that does depend on how you define "efficiency"). But, at the same time, they also point out that there may be opportunities in synthetic biology to improve on photosynthesis.
After our of recent articles on different ways of splitting water into hydrogen and oxygen using only sunlight and catalysts as a kind of artificial photosynthesis, it is interesting to have the perspective of this article, which is to be published in an upcoming issue of the magazine Science.
While standard photovoltaics can just produce electrons when they are able, plant photosynthesis needs to be able to sustain the plant at all times, or else it will die. For this reason, plant photosynthesis is more stable and robust, but at the same time, is less idealized to maximize energy production. The paper also discusses ways of making photovoltaic collectors more efficient by taking cues from the photosynthetic process.
"The point of the comparison is not to make us throw plants on the compost pile, the researchers said. For one, efficiency is only one consideration among many in the choice among energy technologies. More important are life-cycle costs, the capital cost and valuation of the environmental impact of a product from its creation to its destruction."
All factors including life-cycle costs, energy inputs, infrastructure requirements, and greenhouse gas balance need to be examined in order to determine the greatest total efficiency. But even if this a clear leader in efficiency, that should not necessarily result in dumping all technology into that one basket. Rather than using this analysis to pick a winner, it should serve to help improve other ways of doing things. Looking at the benefits each approach offers can give direction for how to improve the efficiency of other systems.
As an interesting aside, Dr. Daniel Nocera, the developer of the Sun Catalytix system is one of the several co-authors of this paper.
[Edited to correct spelling of Nocera]
written by Robin, May 18, 2011
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