Ligno-Cellulosic Ethanol Fact Sheet
Cellulosic Ethanol Production
Most plant matter is not sugar or
starch, but cellulose, hemicellulose,
and lignin. The green part of a plant is
composed nearly entirely of these three
components. To convert cellulose to
ethanol, two key steps must occur:
Cellulosic Materials
Benefits of Cellulosic Ethanol
Agricultural Waste, Forest Waste, Municipal
Solid Waste & Dedicated Energy Crops
1) Saccharification: A variety of
thermal, chemical, and biological
processes are used to break
cellulose down into sugars. This
step is a major challenge.
2) Fermentation: The sugars must be
fermented to make ethanol, similar
to the grain-to-ethanol process.
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 Access to wider array of potential
feedstock, including waste cellulosic
materials and dedicated cellulosic
crops.
 Greater avoidance of conflicts with
land use for food production
 Greater displacement of fossil energy
per litre of fuel, due to nearly
completely biomass-powered
systems.
 Much lower net greenhouse gas
emissions than with grain-to-ethanol
production powered primarily by fossil
energy.
Greenhouse Gas Reduction Impacts
Producing ethanol from cellulosic feedstock has the potential
to achieve greater greenhouse gas (GHG) reductions than
grain-based ethanol. The use of cellulosic feedstock in
producing ethanol has a “double value” in that the left over
(mainly lignin) parts of the plant can be used as process fuel
to fire boiler fermentation systems. This makes for both a
relatively more energy-efficient production process and a
more renewable approach since fossil energy use for
feedstock conversion can be kept to a minimum.
Typical estimates for net GHG emissions reduction from
production and use of cellulosic ethanol are in the range of
70% to 90% compared to conventional gasoline. Net GHG
reductions can be boosted even further if the electricity
produced by cogeneration facilities is used to displace coalfired power on the grid.
Production Costs
Cellulosic ethanol requires much greater processing than grain or sugar-based ethanol, but feedstock costs for grasses and trees
are generally lower. If targeted reductions in conversion costs can be achieved, the total costs of producing cellulosic ethanol could
fall below that of grain ethanol.
There are no large-scale commercial cellulosic ethanol plants currently in operation, by the National Renewable Energy Laboratory
estimates that in the near-term, it would cost a large-scale facility about $1.36 per gallon to produce cellulosic ethanol. The
Department of Energy (DOE) has set a goal of bringing down the overall production costs to $1.07 per gallon by 2012.
Gasification
Research & Initiatives
Gasification is an alternative production technology that
does not rely on chemical decomposition of the cellulose.
 Millions of research dollars are focused on developing more
efficient separation, extraction, and conversion techniques.
 A key research area is enzymatic hydrolysis processes, which
is believed to have the potential to improve the efficiency and
lower the cost of cellulosic ethanol production.
 The DOE recently awarded grants totaling $385 million over 4
years in 6 companies working on cellulosic ethanol plants.
 The Department of Agriculture is seeking to increase its
bioenergy financing to $161 million from $122 million, including
$21 million in loan guarantees for cellulosic ethanol plants.
 In the early part of 2007, venture capital firms, Wall Street, and
even oil companies have invested approximately $200 million
in cellulosic ethanol development.
Instead of breaking the cellulose into sugar molecules, the
carbon in the raw material is converted into synthetic gas
(syngas), a mixture of carbon monoxide and hydrogen.
The syngas can then be converted to diesel (via FischerTropsch (FT) synthesis), methanol, or dimethyl ether- a
gaseous fuel similar to propane. Alternatively, the
hydrogen can be separated and used as fuel.
Currently, most interest exists in the production of diesel
via FT synthesis- the same technology used in gas-toliquids and coal-to-liquids plants.