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Questions & Answers

The AHB project concluded in 2019. What is the future of poplar-based biofuels?

As of 2019, poplar-based biofuels are not economically viable. Biorefineries for poplar-based chemicals may be economically feasible, especially if poplar is also grown to provide environmental services (e.g., wastewater treatment, flood mitigation.) Researchers, industries, and community leaders continue to explore these possibilities.

What are advanced biofuels?

Advanced biofuels are renewable fuels produced from inedible plant parts, wood chips and shavings, and other waste products. These biofuels are considered environmentally friendlier than their food-crop counterparts such as corn ethanol.

What are bioproducts?

Bioproducts or bio-based products are materials and chemicals produced from renewable biological sources such as plants or algae. High-value co-products can be produced from woody biomass as early steps in the conversion process to fuel. These chemicals can be used to make paints, plastics, solvents, packaging, pharmaceuticals, cosmetics, and even nutritional supplements and textiles.

What biochemicals can be made from poplar?

Poplar wood can be made into a variety of chemicals that are used to make everyday products. These chemicals are traditionally produced from petroleum, but instead can be made from locally sourced, renewable resources.

  • Acetic Acid – found in road de-icing salts, paint, and solvents.
  • Ethyl acetate – found in nail polish remover and cosmetics, and used to decaffeinate coffee.
  • Ethylene – a gas used to make plastics such as bags and water bottles, and used to ripen fruit.

How do advanced biofuels differ from corn ethanol?

Advanced biofuels feedstocks are produced from inedible plant parts such as agriculture crops and forest residues. Marginally productive land can support advanced biofuel feedstocks with only minimal nutrient and water inputs making them more energy efficient. The carbon emissions are also reduced by 50% compared to traditional biofuel crops such as corn.

What is the Renewable Fuel Standard (RFS)?

The U.S. Renewable Fuel Standard (RFS) is a federal program established under the Energy Policy Act of 2005 that requires transportation fuel sold in the U.S. to contain a minimum volume of renewable fuels.

The Energy Independence and Security Act of 2007 extended and expanded this program and became the RFS2. This program requires production of 36 billion gallons of renewable fuels each year by 2022, 16 billion gallons of the target are to be procured from cellulosic biomass.

Each renewable fuel category in the program must emit lower levels of greenhouse gases relative to the petroleum fuel it replaces.

Why make biochemicals; why not stick to biofuels?

Biochemicals require fewer steps to produce, and are often higher in value than liquid biofuels. Because of the volatility of fuel prices, it is hard for biofuels to compete in the market. Creating a bioeconomy that includes bio-based chemicals in addition to biofuels can help establish biorefineries as economically viable enterprises.

What are hardwoods?

Hardwoods refer to broad-leaved, deciduous trees, which usually lose leaves during fall/winter in temperate zones. These are flowering and fruiting trees (angiosperms) that include oak, ash, maple, alder, and poplars. In contrast, softwoods refer to coniferous or cone-bearing trees (gymnosperms). Examples of these include fir, pine, hemlock, and spruce.

Hardwoods generally have a harder, denser and more complex wood structure than softwoods, but not always, as there is wide variation among species, with some “hardwoods” being quite soft.

Why are hybrid poplars good for biofuel?

The fast-growing nature of hybrid poplar trees makes them an excellent crop for biofuel production. These trees are highly adaptable to a wide range of sites, including marginal lands that are currently unproductive or underproductive for other types of crops. Hybrid poplar regrows from cut root stalks allowing multiple harvesting rotations from one planting. Harvest can occur year-round allowing for flexible availability to the biorefinery.

Compared to corn, hybrid poplar requires only one-sixth of the fossil energy needed to produce biofuel feedstock, and the need for both fertilizer and chemicals is less. Moreover, compared to other wood sources, it is much easier to convert hybrid poplar into biofuels. The high genetic variation among poplars and many desirable traits provide an opportunity to develop them as ideal feedstock for biofuels.

Can the conversion technology only utilize poplar wood as the feedstock?

The conversion technology has the capability to utilize a wide range of renewable wood and agricultural waste products. Appropriate feedstock is determined by the geographic location of the biorefinery and feedstock resources that available within a short radius, about 50 miles.

Where will the biorefineries be located?

Our economic sustainability researchers are using geospatial modeling to identify suitable biorefinery locations. Biorefineries will likely be located in areas where large poplar bioenergy farms can be established at competitive rates. Site-specific costs for land, rail access, and air pollution control are also factored in to find optimum locations for biorefineries. A demonstration biorefinery has been established in Boardman, OR.

What kind of land are you looking for to grow poplars?

Hybrid poplars can be grown in a wide range of sites. We are investigating lands that are currently unproductive or underproductive for other types of crops.

The land area must be large enough to supply year-round poplar feedstock for a local biorefinery. This can be several large parcels of land or many small parcels that could form a poplar farm cooperative.

Why are we making gasoline, diesel, and jet fuels instead of ethanol?

This project sought to develop renewable fuels in order to further reduce reliance on imported petroleum-based fuels and to increase domestic production. Poplar-based biofuels will be direct replacements for petroleum-based fuels without the need for any modification of existing engines and transportation infrastructure. These ‘drop-in’ fuels can also reduce logistical complications of blending with fossil fuel.

Benefits include reduced carbon emissions, use of domestic forest and agricultural resources, investment and job creation in rural communities, and production of domestic fuels to displace imported fuels.

Why should biofuels be part of our transportation portfolio?

Energy independence, security, and sustainability have become national issues for fossil fuel stocks. Moreover, biofuels help alleviate environmental concerns related to increasing use of fossil fuels.

How are these biofuels chemically different relative to conventional fossil fuels?

These bio-based fuels will have the same chemical composition as petroleum derived fuel and also the same energy content. However, bio-based fuels offer reduced carbon emissions compared to fossil fuels, a key focus of this project.