Petite poplars and the future of biofuels

The researchers harvested poplar trees approximately the size shown in this photo.Chang Dou/University of Washington
The researchers harvested poplar trees approximately the size shown in this photo.Chang Dou/University of Washington

Scientists in the US are working to produce biofuels from poplar that could compete with the oil industry.

The US Pacific Northwest has an abundant supply of poplar, a fast growing and versatile tree whose wood can be transformed into biofuels and high value chemicals. However, even though scientists are exploring poplars’ potential to be used in ethanol production, a commercial-scale processing plant for poplars has yet to be realised.

A team from the University Of Washington (UW) is testing the potential for biofuel production from younger poplar trees that could be harvested more frequently - after just two to three years instead of the typical 10 to 20 year cycle. These trees are planted closer together and cut in a way that allows more branches to sprout up from the stump after each harvest, using the same root system for up to two decades.

The method is known as coppicing, and the trees called poplar coppice.

The UW team is the first to attempt to convert the entire poplar coppice – leaves, bark and stems – into bio oil and ethanol. Their results, which have just been published in the journal Chemistry and Engineering, seem to suggest there is a future for poplar coppice in biofuel production.

“Our research proved that poplar coppice can be a good option to meet the cheap, high-volume criteria of biofuel feedstock,” said lead author Chang Dou, a doctoral student in the UW’s Bioresource Science and Engineering Programme. “Our findings are significant for the future biofuel industry, and the ultimate goal is to make poplar coppice biofuel a step closer to the pump.”

 

Competitive

The UW researchers believe that poplar coppice has the potential to create alternative fuels that ‘make economic sense’ and could therefore be competitive in the petroleum dominated fuel market.

“We have the environmental incentives to produce fuels and chemicals from renewable resources, but right now, they aren’t enough to compete with low oil prices. That’s the problem,” said Renata Bura, a UW associate professor in the School of Environmental and Forest Sciences and the senior author.

Ultimately, the researchers believe that coppice poplar is likely to be the best balance of cost and reliability for Pacific Northwest growers to produce biofuels.

“Currently, we are looking at how we can grow poplar for monetised ecosystem services,” Bura said. “In the future, we envision a bio-based industry that will provide multiple environmental benefits, will invigorate rural communities and will serve as a bridge to a fully developed biofuels industry.”

More information about the team’s research is available from the University of Washington website.

The researchers harvested poplar trees approximately the size shown in this photo.Chang Dou/University of Washington