Biomass Feasibility Project Final Report - Xcel Energy

Ethanol has been hailed as a move toward energy independence, which is an important
geopolitical goal. But from an environmental standpoint, ethanol is a paradox: a renewable
biomass fuel that replaces one fossil fuel, petroleum, by using two other fossil fuels, natural gas
and coal in the form of electricity. These are American fossil fuels rather than Middle Eastern
fossil fuels, but they are fossil fuels nonetheless.
Some critics argue that making ethanol takes as much energy as the finished product contains.
Industry spokespersons counter that the ratio really is more like one unit of input energy to 1.3
units of ethanol energy. However, it is clear that the most ethanol plants draw on fossil fuels from
distant regions and neglect renewable biomass fuels that lie around the plants.
Ethanol expansion will run into natural limitations at some point because even renewable
resources are finite. Ethanol plants consume lots of water – four to six gallons of it per gallon of
fuel produced. Lack of adequate groundwater already is limiting the development of ethanol
plants in some areas of southwestern Minnesota. Another problem is the very select feedstock
used to make ethanol. It is becoming difficult to site a new plant without overlapping another
plant’s corn procurement area. Recent coverage of the industry suggests that if all of the
ethanol plants seeking permits in Minnesota are built, they will consume more than 40% of the
state’s corn crop (Webb, 2006). The food and feed industries are concerned that they are
being priced out of their traditional markets by fuel producers.
The ethanol industry will continue to expand, however, as it learns to conserve water, expand its
raw material base with wastes like stover and straw by adopting cellulosic processes, and
generate its own gas and electricity through gasification of agricultural biomass. Like paper
mills, ethanol plants may even become power plants of the future, generating electricity not just
for themselves but also for surrounding communities.
Biomass Energy in Ethanol Plants
The ethanol industry already is moving toward greater energy efficiency. Three Minnesota
ethanol producers are working toward becoming self-sufficient in energy by installing new
technologies. One is using a fluidized-bed boiler, one is using a gasifier, and another is planning
to install one. The immediate goals for projects are reducing costs and meeting tougher
environmental regulations. But there is a longer-term justification as well. If subsidies for ethanol
production eventually decline or even disappear, these plants will be better prepared to
compete head-on against other fuels.
There is another potential benefit from investments that capture more energy through
advanced technologies like gasification and biorefining. Once a plant becomes self-sufficient
in electric power, exporting power is just one step further along the same path. At the moment,
only one Minnesota ethanol plant is exporting power – Central Minnesota Ethanol Cooperative
(CMEC), which sells all of one megawatt to Xcel Energy. Like most other ethanol plants
considering gasification, CMEC’s primary interest is in substituting syngas for ever more expensive
natural gas. That is an easy substitution because once it is cleaned, syngas burns well in an
existing, unmodified natural gas boiler. In the future, a gasifier might fuel a turbine generator
producing enough electricity to power the plant and sell to the grid besides. To get to that
export stage, however, a plant will have to find additional sources of biomass fuel.
Corn Plus Ethanol in Winnebago
Corn Plus General Manager Keith Kor has taken several steps to make Corn Plus’ 44-milliongallon
plant more energy-efficient, beginning with the installation of internal heat transfers that
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Identifying Effective Biomass Strategies:
Quantifying Minnesota’s Resources and Evaluating Future Opportunities