Direct utilization of solar vs. biofuels. Verdict: direct solar wins by a huge margin
Submitted by Anonymous on Tue, 02/10/2009 - 06:47.
So, I came across this article that really put into perspective the inefficiency of biofuels. http://www.ecogeek.org/content/view/1454/70/ According to this article, solar power (presumably from photovoltaics, which would be at about 15% efficiency) yields the energy to drive 2,250,000 miles per acre of land used per year of sun exposure, whereas algae based biodiesel would only yield the energy needed to drive 370,000 miles per acre per year. If this is so, imagine the yields using higher efficiency systems, like solar thermal, which yield twice the efficiency of conventional photovoltaics. Plants, it seem, are very inefficient compared to artificial solar technologies. The most efficient photosynthesis carried out by a plant maxes out at 1%. The miscanthus grass is the most efficient photosynthesizer, yet its efficiency is only a tiny fraction of the efficiency of our average photovoltaics: http://www.treehugger.com/files/2008/07/miscanthus-field-trials.php If what they say is true, from now on, view all articles on the development of biofuels with this in mind. Most biofuels have a conversion efficiency of solar energy (after processing and transport) of less than 1%.