New, clean energy source: Living plants

Saturday, December 01, 2012 by: David Gutierrez, staff writer
Tags: clean energy, plants, photosynthesis

(NaturalNews) On November 23, a researcher from Wageningen University in the Netherlands, Marjolein Helder, presented her Ph.D. research on a method to generate clean, renewable electricity from natural interactions between the soil and growing plants.

Plants produce such enormous quantities of organic material from photosynthesis that they actually excrete 70 percent of it, unused, into the soil by their roots. This provides important nutrients for bacteria and other soil organisms. When bacteria metabolize this organic matter, they release electrons into the soil. The premise of the Plant-Microbial Fuel Cell is that electrodes placed close to the roots of plants can absorb these electrons and use them to generate electricity, much like a battery.

Helder's tests indicate that the Plant-Microbial Fuel Cell can generate 0.4 W of electricity per square meter of vegetated area, more than biomass fermentation is currently capable of. Through further refinement of the technique, Helder predicts that its power generating capacity could rise as high as 3.2 W per square meter. This level of power generation would enable the average household to be supplied entirely from the power generated by grass planted on a 100 square-meter roof.

A future global energy source?

According to Helder, much of the technique's potential lies in its adaptability. Various species of plants have high electric generating potential, including many grasses and even rice. The system should also scale up effectively, thereby converting marshlands into critical sites for power generation. Helder predicts that the system will be widely deployed on rooftops within a few years, and that large-scale generation will be implemented by 2016. Due to their low cost, the systems could already be economically competitive with solar panels in remote regions, even at their current capacity.

Helder also researched the social and environmental implications of the technology, concluding that it is more promising than other non-fossil fuel sources. Unlike nuclear power or hydroelectric dams, the system should have no negative effects on natural systems. In contrast to biofuels, it would not encourage habitat destruction or the removal of agricultural lands from food production. And unlike solar panels or wind turbines, the system would be visually appealing, rather than an eyesore.

If the system is widely adopted enough to turn wetlands into a power source, that alone could provide another benefit. According to a research summary just published by University of Gothenburg, in Sweden and the Swedish University of Agricultural Sciences, drained wetlands account for the same percentage of Sweden's greenhouse gas emissions as all of its industries combined.

Research is ongoing on ways to increase the Plant-Microbial Fuel Cell system's capacity, and to verify the best methods for making it both sustainable and renewable. Optimum electrode placement, for example, could decrease material use by two thirds.

Researcher Bert Hamelers was the first to suggest the potential of a Plant-Microbial Fuel Cell, and the first tests were carried out by researcher David Strik. Strik and Helder have since founded a spin-off company to commercialize the system.

Sources for this article include:
http://www.sciencedaily.com/releases/2012/11/121123092129.htm
http://www.sciencedaily.com/releases/2012/11/121123092742.htm