Researchers at the KTH Royal Institute of Technology have managed to harvest energy by taking advantage of the transpiration of wood. This process in which water moves through a plant occurs constantly in nature. It produces small amounts of electricity, known as bioelectricity.
Yuanyuan Li, an adjunct professor in KTH’s Biocomposites division, says that with a little nanoengineering of wood – and by adjusting the pH – small but promising amounts of electricity can be obtained.
It already works with small devices
“At the moment we can run small devices, such as an LED lamp or a calculator,” Li explains in a statement. “If we wanted to power a laptop, we would need about a square meter of 1-centimetre-thick wood and about 2 liters of water. For a typical home we would need a lot more material and water than that, so further research is needed.”
By altering the nanoscale composition of wood, the researchers improved its properties in terms of surface area, porosity (or density), surface charge, ease with which water can pass through the material, and the aqueous solution itself, all of which influence the generation of electricity in wood. “We compared the porous structure of normal wood with the material we upgraded in terms of surface area, porosity, surface charge, and water transport. Our measurements showed 10 times higher electricity generation than natural wood,” Li says.
High voltage for 2-3 hours
Li says that, to date, the wood manages to supply a high voltage for about 2-3 hours, before it starts to decay. So far, the wood has made it through 10 water cycles without diminishing performance, he says.
“The great advantage of this technology is that the wood can easily be used for other purposes once it is exhausted as an energy source, such as transparent paper, wood foam and different biocomposites.”