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On Wednesday, the Academy of Science and Skandalaris Center hosted a very interesting lecture on the prospects for renewable bio-energy. Speaking were Dr. Lars Angenent, Assistant Professor of Energy, Environmental, and Chemical Engineering at Wash U, and Nick Akers, President of Akermin, Inc. The presentations covered both the larger need for renewable energy and how their teams are approaching the problem, and the whole event reminded me of several lectures I heard in San Diego last year.
Dr. Lars Angenent
Both speakers are approaching bioenergy from different angles. Dr. Angenent's team specializes in Microbial Fuel Cells (MFC's), battery-type devices that use microbe-covered electrodes to generate energy. One big plus of this approach is its adaptability for a huge range of fuels. In fact, the Wash U group, and many others, are interested in generating electricity from urban sewage, not a small prospect considering wastewater treatment can make up as much as 50% of urban power consumption in the U.S.
Akermin is interested in an entirely different goal: high-efficiency alcohol-fueled devices to compete with consumer lithium-ion batteries. Instead of growing colonies of electron-spitting microbes in their fuel cells, Nick Akers and his team attach electrochemically active proteins to carbon electrodes, increasing the energy yield per surface area.
People have talked about bioenergy devices for at least 20 years, partly because the idea is just cool, but also because it syncs up with what we see in nature. By far the most efficient solar-cells on the planet are the chloroplasts in a common weed; the muscle in my little finger has a better power conversion than the most advanced auto engine. But it’s also important to remember that the cells and proteins we try to harness for industry have spent millions of years optimizing themselves, not for use in batteries, but survival.
Why does this matter? The products that these bio-devices are aiming to replace, namely traditional metal and ceramic batteries, have their own problems. However, energy yield per square inch of electrode isn't one of them (Pt-Oxygen fuel cells have a very favorable reducing potential, they just cost a lot). The direction that biotech always wins, though, is in flexibility. How many car batteries could operate off of sewage, or oil spills, or the glucose in human blood?
For all I know, Akermin and Wash U have already made bio-fuel cells that can outpace their metal counterpoints. Even if they haven't, though, the idea of producing energy from biological materials is one with enormous potential.
On a side note, Nick Akers also took the opportunity to talk about the new Center for Evergreen Energy, announced at the recent DOE Renewable Energy Conference. Worth keeping an eye on.
