From Bio to Fuel

A look at shrub willow and cellulosic diesel to address our energy needs

Shrub Willow: Coming to Marginal Land Near You

What is it?

Shrub willow is related to weeping willow, but it is smaller, has more than one “trunk,” and grows back easily after being cut down. It’s in a trio of willow groups that includes shrubs, dwarf alpine willows, and trees. Native Americans chewed willow bark and young twigs to relieve headaches, and a compound found there later became the basis of aspirin.

Why is it of interest?

Propagated with unrooted cuttings that grow rapidly, shrub willow thrives on substandard land and doesn’t compete with food plants. The roots remain as in-ground carbon reservoirs, and the shrubs grow back quickly after cutting, replenishing above-ground carbon. The plant can be mechanically harvested, and its attractive foliage creates inviting landscapes and habitats for birds and mammals.

Where does it grow?

In North America, shrub willow is being planted as an energy crop mainly in the Northeast, Midwest and southern Canada. In Europe, it’s grown for bioenergy mostly in Sweden, Denmark, Northern Ireland, and the United Kingdom. Scientists in Germany, Eastern Europe and parts of Asia have also expressed interest.

Why does it matter?

Besides being very productive, willow can grow for 20 years before replanting is needed. It also grows well without irrigation or pesticides.

What’s next?

Willow wood chips can be turned into pellets and used to produce heat and/or electricity. Scientists are also working on willow shrub as a source for transportation biofuel.

Who is working on it?

The list includes Cornell University; SUNY-ESF; the states of Delaware, Maryland, New Jersey and Pennsylvania; and several European countries. Willow continues to find markets other than energy: in fences, baskets, fish traps, wicker furniture and – in the UK at least – biodegradable caskets.


Cellulosic Diesel from Pine Wood Chips


What is it?

In the spring of 2013, the venture capital-backed start-up KiOR, which went public in 2011, began shipping cellulosic diesel made from pine wood chips from its facility in Columbus, Miss. The chips were previously used to power a paper mill in Columbus that has since been shut down. (Note from the editors: KiOR declared bankruptcy in late 2014.)

How does it work?

The company says that its technology platform “combines its proprietary catalyst systems with a process based on existing Fluid Catalytic Cracking (FCC) technology, a standard process used for over 60 years in oil refining.” KiOR’s CEO has declared that its process “has the potential to resurrect each and every shut down paper mill in the United States.” Although KiOR missed its production targets in the third quarter of 2013, its output was substantially higher.

Why does it matter?

Unlike traditional biofuels like ethanol or biodiesel, KiOR’s fuels have no compatibility issues with engines in the U.S. vehicle fleet. KiOr’s drop-in renewable gasoline blendstock is also the first renewable cellulosic gasoline – or gasoline made from the non-food parts of plants – to be registered by the Environmental Protection Agency for sale in the United States.

Where can I read more?

Biofuels Digest has covered the KiOR story extensively. Check out the archives and new updates at


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