Comparing energy conversion of plants and solar cells

Jan 16, 2012 By Sharon Durham
Comparing energy conversion of plants and solar cells
A team of scientists has devised a new way to more accurately compare how efficiently plants and photovoltaic, or solar, cells convert sunlight into energy, which could ultimately help researchers improve plant photosynthesis, a critical first link to enhancing the global supply of food, feed, fiber and bioenergy. Credit: Institute for Genomic Biology/University of Illinois.

Scientists now have a way to more accurately compare how efficiently plants and photovoltaic, or solar, cells convert sunlight into energy, thanks to findings by a research consortium that included a U.S. Department of Agriculture (USDA) scientist.

The study, published in Science, could help researchers improve plant photosynthesis, a critical first link in the for food, feed, fiber and bioenergy production.

Comparing plant and photovoltaic systems is a challenge. Although both processes harvest energy from sunlight, they use that energy in different ways. Plants convert the sun's energy into chemical energy, whereas solar cells produce electricity. The scientists, including Agricultural Research Service (ARS) research leader Donald Ort in the agency's Global Change and Photosynthesis Research Unit in Urbana, Ill., identified specific designs that hold excellent promise for improving efficiency.

The first step was to facilitate a direct comparison of the two systems. The researchers set a uniform basis for the comparison and examined the major factors that define the efficiencies of both processes, first considering current technology, then looking forward to possible strategies for improvements.

In all cases, the research team considered the efficiency of harvesting the entire as a basis for comparison. Additionally, the researchers compared plants to solar cell arrays that also store energy in . Calculations were applied to a solar cell array that was coupled to an electrolyzer that used electricity from the array to split water into hydrogen and oxygen. The free energy needed to split water is essentially the same as that needed for photosynthesis or a solar cell, so the comparison provided a level playing field.

Using this type of calculation, the annual averaged efficiency of solar-cell-driven electrolysis is about 10 percent. efficiencies for are about 1 percent, which illustrates the significant potential to improve the efficiency of the natural system, according to Ort. While, in the context of the team's efficiency analysis, solar cells have a clear advantage compared to photosynthesis, there is a need to apply both in the service of sustainable energy conversion for the future.

This energy-efficiency analysis between plant photosynthesis and will lay the groundwork for improving the efficiency of plant photosynthesis in agriculture for improved yield.

Explore further: Environmentally compatible organic solar cells

Provided by USDA Agricultural Research Service

2.3 /5 (3 votes)

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1 / 5 (1) Jan 16, 2012
"The study could help researchers improve plant photosynthesis, ..."

What makes you think a scientist or even a massive collaboration of them could "improve" a plant process that has evolved for billions of years.

What they SHOULD have done was protect the wildlife, all of it, 50 years ago. Half the rain forest or more is gone, I have heard startling rumors of 70-80% gone. Maybe even 90% like our oceans.

Life may be resilient but every species we lose has unique chemicals in them and are already the best possible producers of those chemicals given to us, all you do is input and they output a processed thing. If you think you can upgrade that you are mistaken, you may eventually be able to fully understand and replicate that symbiosis but improving on something so complex is far in our future and even then there will be intense ethical unknowns.
not rated yet Jan 17, 2012
The future will be a product of the desperate search to support ever greater populations of the planet. Bio tech will become the rule, not the exception. People who are miserable and hungry and scared will continue to chop down jungles and forests regardless of sustainability because their other choice is to just perish.
not rated yet Jan 23, 2012
Very interesting, hopefully this will lead to further funding and investment in this needed industry. I posted a few updates on solar in Europe

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