"I have a slide that has a photo of a cornfield and a big photovoltaic array," says Robert Blankenship, a scientist who studies photosynthesis at Washington University in St. Louis. "When I give talks I often ask the audience which one is more efficient. Invariably the audience votes overwhelmingly in favor of photosynthesis. "
They are wrong.
This question and its surprising answer (below) is the point of departure for a provocative article published in the May 13 issue of Science. The article is the outgrowth of a Department of Energy workshop comparing the efficiency of plants and solar cells, a topic Blankenship, a member of the DOE's Council and Biochemical Sciences, had suggested.
"We assembled a team of distinguished biologists, chemists, physicists and solid-state scientists and met in Albuquerque in May 2009 to hash everything out," says Blankenship, PhD, the Lucille P. Markey Distinguished Professor of Arts and Sciences in the departments of biology and chemistry. "It turned out that we knew a lot, but what we knew existed in two parallel universes," he says.
"The paper tries to resolve the long-standing controversy over the efficience of photosynthesis," says David M. Kramer, PhD, the Hannah Professor of Biochemistry and Molecular Biology at Michigan State University and one of the co-authors. "The efficiency of photosynthesis, and our ability to improve it, is critcal to whether the entire biofuels industry is viable."
Which is more efficient?
The question really isn't a fair one unless efficiency is first defined. At a bare minimum it isn't fair to compare plants that package the sun's energy in handy little stored-fuel packages (carbon-based molecules) to photovoltaics that just take the first step of converting the sun's energy to jazzed-up electrons.
Fairer would be to compare plants to photovoltaic arrays that also store energy in chemical bonds. So the experts did
|Contact: Diana Lutz|
Washington University in St. Louis