Scientists in the US are examining the way plants convert solar energy into liquid fuels, and have found that although photosynthesis in plants produces less energy from sunlight than man-made solar cells, genetic modifications could lead to cheap bio-solar power.
According to David Kramer, Hannah Distinguished Professor of Photosynthesis and Bioenergetics at Michigan State University, photosynthesis evolved to help power a living thing; get the balance of solar conversion wrong and the whole system becomes toxic to life. Solar cells, on the other hand, produce more energy because they need only send electricity down a wire.
Kramer is a lead researcher and the co-author of a paper published in the latest issue of Science magazine which attempts to answer the question of whether photovoltaic (PV) solar cells are more efficient than photosynthesis.
The paper found that in plants, up to 80 percent of absorbed solar energy is dumped to avoid killing the organism, leading to an annual energy efficiency of 1-4 percent. Solar PV cells provide more than 10 percent. The paper’s authors believe that through bio-engineering, plants could produce and store more solar power.
"This is critical since it’s the process that powers all of life in our ecosystem," Kramer says. "The efficiency of photosynthesis, and our ability to improve it, is critical to whether the entire biofuels industry is viable."
The experts suggest splicing the light-absorbing characteristics of a species of bacteria, called cyanobacteria, into the photosystems of crop plants. The bacteria gather light from a different part of the solar spectrum, which would in essence double the light-absorbing capability of individual plants. Basically, the researchers say, it would be the biological equivalent of a tandem solar cell, which is very efficient.
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