from wheat staw. In Sweden, a fully integrated pilot plant
for ethanol production from softwood, comprising both twostage
dilute acid hydrolysis and the enzymatic process, was
taken into operation in mid 2004. The pilot has a maximum
capacity of 2 ton (DM) wood per day (http://www.etek.se).
The step from pilot- and demo-scale production of lignocellulosic
ethanol to competitive full-scale production
requires further reduction of the production cost. One
approach to this is the integration of ethanol production
with a combined heat and power plant (Figure 5) or with a
pulp and paper mill. This has been estimated to reduce the
ethanol production cost by up to 20 percent for conditions
prevailing in Sweden [65] and it is the main strategy
pursued in the Swedish cellulosic ethanol effort. Similar
conclusions were reached in a study on co-production of
ethanol and electricity from softwood, based on conditions
in California. Another option is to integrate cellulosic
ethanol production with starch-based ethanol production
to use the whole agricultural crop. For the immediate
future, we believe that these integrated plant concepts
will be used in the first successful industrial scale production
of lignocellulosic fuel ethanol. The transition of lignocellulosic
fuel ethanol production into a mature
industrial technology requires research and development
efforts in the areas summarized in Box 2.