Waste wood may find new purpose as biofuel and chemicals

MADISON, Wis. – Recent years have been difficult for pulp and paper mills of the Great Lakes region. As some mills idle their machines and others shut down operations entirely, the industry looks toward new innovations and alternative forest products to ensure its viability into the future. One such promising innovation is the integration of practices to convert waste wood into valuable byproducts, such as commodity chemicals.

“My vision of the pulp and paper industry of the future includes the process of feeding in wood, taking the cellulose and making pulp, and then extracting the lignin to make higher value chemicals and products,” said Dr. George Huber, a professor in the Biological and Chemical Engineering Department at UW-Madison.

Along with useful chemicals, wood and other forms of biomass can be converted into biofuels in the form of gasoline, diesel fuel, and jet fuel. The term biomass encompasses a variety of organic materials, including wood, energy crops, waste from forests and farms, and oils. Huber’s research focuses on developing more efficient ways to convert these forms of biomass into useful products. He and his collaborators Professor Jim Dumesic and Hochan Chang were recently nominated for the 2021 Wisconsin Alumni Research Foundation Innovation Awards for their research.

Huber has seen both the rising and falling of public interest in biomass during his over twenty years of conducting research in this field. Early on the biofuel effort in the U.S. was largely driven by a desire for energy independence, but with the development of fracking and natural gas in the 2010s, the interest was curbed. More recently, interest has again been renewed, this time led by consumers seeking more environmentally friendly solutions.

Still, the sustainability of biofuels themselves has been questioned because growing crops for biomass feedstock requires areas of farmland that could otherwise be used for food crops. A growing global demand for food and an expanding biofuel sector could result in increased deforestation due to land conversion from forests to agriculture.

According to Huber, wood is a very promising form of biomass. It is the most abundant, sustainable, and cheapest material to use in this process. Using wood waste and wood from sustainably managed forests can provide a more sustainable source of biomass that doesn’t compete with food crops. Wood can also be harvested year-round, giving it an advantage over agricultural crops which tend to be harvested once a year and require storage for year-round processing.

The components of wood waste can be broken down and converted into valuable chemicals with a variety of uses, but many pulp and paper mills tend to burn their waste byproducts for heat rather than extracting and selling the useful components. Some mills in Europe are beginning to adapt and integrate their operations to take advantage of biomass conversion into fuel and chemicals.

While Huber believes this integration would be a valuable shift for the pulp and paper industry, he acknowledges that it comes with significant financial challenges. The overarching goal of his research is to develop biomass conversion practices that are clean and economically feasible. His research team is currently focusing on high value chemicals that are worth $2,000-6,000 per ton. Co-producing these enhanced chemicals could help supplement the lower value of traditional products.

It remains difficult for biomass to reach an economy of scale. To help create a commercially viable operation using the biomass conversion method studied in his lab, Huber co-founded the company Anellotech, which uses a species of pine for the biomass feedstock. Huber was also involved with launching Pyran, a biomass conversion company that uses agricultural crop waste. By collaborating with partners and improving commercialization, the two companies are trying to bring biomass-based products to global markets.

According to Huber, launching Pyran required tens of millions of dollars and Anellotech required hundreds of millions of dollars. With such a large amount of money on the line, investors have to be confident that the outcome will be worth the risk. Beyond financial considerations, Huber says the sector will also need to be backed by legislation and market demand.

“There is a drive for more low-carbon products, and the only way to get there is biomass,” Huber said. “It’s an exciting time to be in this field. There is a lot of academic interest and a lot of companies adapting. It may be challenging for an established company to innovate and raise the capital, but there is still a shift happening.”

For Huber, there are still many questions to explore on the science side of the equation.

The enhanced chemicals made by his lab have already proven themselves financially valuable, but many of them are different from those produced with petroleum, meaning they also have unique and unknown potential. According to Huber, the next step is increasing production and studying the uses of these chemicals for various applications. They are already used in bio-based plastics that can make everything from consumer goods to medical devices, but with further research they may even provide solutions in the pharmaceutical field and beyond.