Published on January 22nd, 2013 | by Tina Casey0
How To Squeeze More Biofuel From Willow: Give It A Twist
Just last month we noted in passing that researchers at the U.K.’s Imperial College London have been developing a new way to unlock the full biofuel potential of ordinary willow, and now the school has released more details on the willow biofuel project. After observing that willow can yield far more biofuel when it grows at an angle rather than straight up, the team has identified a genetic trait linked to the effect.
Willow might not be the first crop you think of when you think about biofuel, but its significance could be extraordinary not only in the U.K. but here in the U.S. as well.
What researchers had previously observed, was that willow trees cultivated in naturally windswept areas were producing more biofuel than willow in relatively non-windy areas.
The team cultivated willows at a 45 degree angle under controlled conditions, and compared their genetic traits with trees growing naturally at severe angles in an extremely windy site in Scotland.
The key finding was that growing at an angle, under duress, activates a genetic trait that tries to counteract whatever force is pushing the tree sideways.
The end result is that the sugar molecules in the stems of the willow are strengthened into higher-energy sugars, which can be processed into biofuel through fermentation more efficiently than sugars from unstressed trees. The yield is about five times greater for stressed willow than for their non-stressed counterparts.
As research co-leader Dr. Nicholas Brereton explains:
“We’ve known for some time that environmental stresses can cause trees to naturally develop a slightly modified ‘reaction wood’ and that it can be easier to release sugars from this wood. This is an important breakthrough, our study now shows that natural genetic variations are responsible for these differences and this could well be the key to unlocking the future for sustainable bioenergy from willow.”
Willow Biofuel in the U.S.
Willow is already grown widely throughout the U.K., and the new finding could help transition more willow crops to marginal lands that are unsuitable for growing food or animal feed.
Willow could also help the U.S. resolve the food-or-fuel issue. New York State, for example is avidly pursuing willow biofuel research through a major project at Cornell University. As a drought hardy, fast growing, pest resistant biofuel crop, willow requires little or no fertilizer to thrive.
In New York alone, researchers estimate that there are more than one million acres of marginal land available to grow shrub willow for biofuel.
In addition to providing a badly needed cash crop for farmers in economically depressed part of the state, willow biofuel would provide property owners with an alternative to selling or leasing their land for the natural gas drilling method known as fracking, short for hydrofracturing, which has been linked to negative impacts including poor health, water contamination and earthquakes.
Fracking is a particularly urgent issue for New York because, while the state sits on the gas-rich Marcellus shale formation, it also hosts reservoirs that provide drinking water for 8 million people in New York City and the surrounding communities.
More Trees for Better Biofuel
Willow isn’t the only tree that is being pressed into service as a new cash crop for marginal lands. Poplar trees are also emerging as a potential biofuel crop, with China, Israel and the U.S. among the countries racing to develop faster-growing varieties.
Poplar could also provide a sustainability twofer when grown on brownfields and other classified lands. As another tool in the phytoremediation toolkit, poplar is known for its ability to suck toxic substances out of soil.
Meanwhile, a research team in China is using poplar as a biomimicry inspiration, to develop a new “cool roof” coating that mimics the way poplar leaves release heat.
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