World Energy Outlook 2006

for supplying biomass residues would also help improve the cost
competitiveness of the technology. Production costs could fall to close to
$0.25/litre (about $0.40/litre of gasoline equivalent) in the long term (IEA,
2006).
Ligno-Cellulosic Biomass-to-Liquids Gasification Technologies
The other main route for converting ligno-cellulosic biomass into biofuels
involves the gasification of the feedstock to produce synthetic gas (syngas) – a
mixture of carbon monoxide, hydrogen and other compounds. The syngas can
then be converted to diesel (via Fischer-Tropsch synthesis), methanol or
dimethyl ether – a gaseous fuel similar to propane. Alternatively, the hydrogen
can be separated and used as a fuel. Currently, most interest exists in
production of diesel via FT-synthesis – the same technology used in gas-toliquids
and coal-to-liquids plants.
As yet, there is no commercial production of biofuels through gasification,
because of the high cost compared with conventional technologies. However,
a considerable amount of research and development is under way to devise
commercially-viable processes. The main development challenges are
improving the purity of the syngas, scaling up the various processes and
integrating them efficiently. Technologies being developed today typically
involve the use of heat and/or chemicals to break down the biomass into gas,
with little or no microbial action involved. Effort is focused on maximising the
hydrogen yield from such processes. To achieve economies of scale, very large
plants will probably be needed, which will require extensive logistical systems
for gathering and transporting the biomass feedstock (Hamelinck and Faaij,
2005). Demonstration plants have been built in Germany. The current
production cost of FT diesel from biomass is about $0.90 per litre, based on a
woody biomass feedstock price of $3.6/GJ. The cost could decline to $0.70 to
0.80/litre in the long term (IEA, 2006).
Gasification technologies allow for co-gasification of biomass with coal,
providing flexibility of feedstock – an attractive benefit in view of the
uncertainties about future fuel prices and carbon-emission penalties. If
combined with carbon capture and storage equipment to handle the carbon
dioxide released during the syngas-production process, a biomass/coal
feedstock mix could still yield significant net reductions in CO2 emissions.
There is extensive commercial experience with large-scale coal-to-liquids
production, notably in South Africa.
Biomass and Land Needs for Biofuels Production
Producing biofuels on a large scale requires large areas of land. A substantial
increase in conventional biofuels production is likely to depend on significant
412 World Energy Outlook 2006 - FOCUS ON KEY TOPICS