Ligno-Cellulosic Ethanol Fact Sheet

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Ligno-Cellulosic Ethanol Fact Sheet
http//www.neeic.org
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

• Benefits of Cellulosic Ethanol
• 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.

Cellulosic Materials 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.

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
fuelto fire boiler fermentation systems. This
makes for both a relatively more energy-efficient
production process and amore 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 coal-fired 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 Gasification
is an alternative production technology that
does not rely on chemical decomposition of the
cellulose. 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 Fischer-Tropsch (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-to-liquids and coal-to-liquids plants.

• Research Initiatives
• 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.