Argonne National Laboratory

Comparing photosynthetic and photovoltaic efficiencies and recognizing the potential for improvement

May 1, 2011

Comparing photosynthetic and photovoltaic efficiencies is not a simple issue. Both harvest the energy in sunlight, operate in distinctly different ways and produce different types of products: biomass or chemical fuels in the case of natural photosynthesis and non-stored electrical current in the case of photovoltaics. To find common ground for evaluating energy-conversion efficiency, a group of researchers lead by Robert Blankenship of Washington University in St. Louis and Argonne's David Tiede, compare natural photosynthesis with present technologies for photovoltaic-driven electrolysis of water to produce hydrogen. On an annual basis, photovoltaic-driven electrolysis is the more efficient process, yet short-term yields for photosynthetic conversion under optimal conditions come within a factor of 2 or 3 of the photovoltaic benchmark. More ยป