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E-M:/ Biomass Energy and Forest Destruction



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Case Study: Dow Corning Corporation Biomass Cogeneration Plant

Presentation by Terry DeBlaay, Forester, Dow Corning Corporation

Contents

       Plant History
       Early Fuel Procurement Strategies
       Fuel Harvesting and Transport
       Marketplace Changes
       Fuel storage
       Ash disposal
       Other Fuels
       Lessons
       Speaker Information

Plant History

The rise in energy costs in the late 1970s led Dow Corning Corporation
to plan for a new source of power for its manufacturing plant in
Midland,
Michigan. The plant is located near Saginaw Bay, an area with a
well-developed road network and abundant supply of wood. In addition,
the Midland area
is in nonattainment with national air quality standards, so
cleaner-burning fuels and technologies were needed.

Previously, the plant (a joint venture of Dow Chemical and Corning
Corporation) had purchased electricity and burned #6 fuel oil to produce
steam, but
the worldwide energy crisis had caused prices to increase sharply. After
considering many different alternative energy sources including coal,
natural gas,
and nuclear power, Dow Corning settled on wood power.

After a feasibility study to assess the fuel supply, the 22 megawatt
Steam & Electric Cogeneration plant (SECO) was constructed in 1982. The
plant
continues to operate today, making use of wood harvested from forest
stands as well as waste wood. At present, 60% of the fuel supply comes
from wood
harvested from forest sources. The remainder comes from industrial and
commercial waste wood.

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Early Fuel Procurement Strategies

Feasibility studies for SECO revealed that there were 4 million acres of
forested land within a 75-mile radius of the plant. (Seventy-five miles
was
considered to be the most economical distance to haul wood.) Ten percent
of that land was owned by the United States Forest Service, 21 percent
was
owned by the Michigan Department of Natural Resources, and the remainder
was private.  Those land ownership patterns continue to the present. It
was
the 69 percent of the land owned by private landowners that was
considered as appropriate for fuel supply.

Dow Corning established a staff of foresters and wildlife biologists to
work out forest and wildlife management plans with private landowners.
At no cost
to the landowner, SECO staff visit a landowner's property and produce a
Comprehensive Forest Management Plan that meets the needs of the
landowner regarding establishment of wildlife habitat, maintenance of
timber types and generation of income from timber sales.

The typical landowner is an absentee landowner who owns over 160 acres.
Many landowners are interested in providing habitat for game animals
such as
deer, turkey, grouse, rabbit and other animals. The actual harvest is
determined by the goals of the landowner. Aspen, the primary timber type
found in the
region, is harvested and managed using the clearcutting silvicultural
technique to encourage regeneration of the next forest.

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Fuel Harvesting and Transport

Dow Corning contracts with logging crews to carry out the harvest
recommendations. Trees are harvested with feller-bunchers, machines
which cut the
trees and lay them in piles known as skids. These skids are then brought
out of the woods to a central landing location, where they are chipped
and the
chips blown into a semi-trailer for shipment to the plant. In order to
avoid picking up stones or sand while removing wood, contract terms
require the
landing area use a paved surface or a 12-inch bed of wood.

Terry DeBlaay refers to some of the difficulties in balancing multiple
land use goals as "biopolitics." For example, landowners often want
small stands of
trees to serve for deer stands. However, these trees limit the
regeneration of the forest due to competition for sunlight.

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Marketplace Changes

Early on in the plant operation, one-half of the fuel supply was met
with sawmill waste wood. As the Michigan wood power industry grew,
additional
plants were built closer to the sawmills that produced much of the waste
wood. As competition grew, supplies were reduced for SECO. The result
was that
SECO had to adjust their procurement plan to new sources.



As a result of the shift in supply, Dow Corning moved to use of urban
and industrial waste wood from the southeast part of the state, mostly
from the
automotive industry. At present, 85-90% of the urban and industrial
waste used by the plant is from scrap pallets. These pallets are ground
up in a tub
grinder to uniform sizes of 1/4 to 3-inch pieces. Sizes smaller than
this generate airborne wood dust, which becomes a nuisance. Wood dust
can clog air
filters used in the production plant. All nonforest sources of wood must
be magnetically separated before being delivered to the plant. Non-wood
contamination (plastic or cardboard) is currently removed by hand, but
SECO is investigating air separation. Plastics are not allowed by
regulation into the
boilers of the SECO plant.

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Fuel storage

"Just-In-Time" inventory is standard Dow Corning procurement practice.
Due to this practice, the company maintains a maximum five day
inventory, and
two to three days inventory on average. The fuel is stored in three
cement silos to reduce fugitive dust. The silos have the added benefit
of protecting the
fuel stores from the elements. On the other hand, outdoor piles of wood
allow larger supplies to be stored.

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Other fuels

As SECO had to adjust to changing market conditions, they experimented
with many different types of biomass resources. SECO's experience
illustrates
many challenges of using biomass fuels.

Waste corn was available in large supply at certain times of the year.
However, the equipment used by SECO was not designed to handle corn,
which
would have rolled back down the inclined conveyor belts. Because of the
seasonal nature of the corn supply, it didn't make sense to modify the
system to
accommodate the corn. Agricultural residues, in general, are very
seasonal and provide an inconsistent supply. Other examples of
agricultural residues
include sugar beet pulp, which was difficult to handle and had high
moisture content, and paprika grindings, which were too dusty to handle.
Horse
manure was high in energy content, but became a pungent nuisance after
rainfall. Also, the waste from race tracks contained chemicals that had
been given
to the horses.

SECO purchased 4,000 acres to provide a backup fuel supply and
demonstration harvest sites. Hybrid poplars were planted on some of this
land, but were
not able to compete with natural vegetation. The energy crops require
cultivation in early years that absentee landowners do not provide, so
the experiment
was not successful.

Tire-derived-fuel (TDF) was tested at the plant and found to work well.
However, due to regulatory prohibitions, TDF could not be used.

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Ash disposal

The SECO plant generates 40 cubic yards of ash per day. The plant has a
ready- made market for the ash in the acid quench ponds at the chemical
plant
on the premises. Recently, SECO received an agricultural land use permit
to spread the ash in dry form on farm land as a fertilizer.

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Lessons

The SECO plant is considered a success by the Dow Corning Corporation.
The $36 million cogeneration plant was paid off in energy savings in
less than
four years. In addition, many thousands of tons of wood wastes were kept
out of landfills. Terry DeBlaay shared a number of lessons that SECO has

learned:

       Work closely with a few number of larger suppliers rather than a
large number of small suppliers. Supplies are more reliable with these
long-term
       contracts. Working with more suppliers is more difficult and is a
less efficient use of resources.
       Be careful in accepting resource assessment studies which promise
huge supplies of unused wood. There is a big difference between gross
       volumes and what is economically viable to recover and use.
DeBlaay cited the example of the Michigan DNR in Lansing stating there
was room
       for two to three more wood-fired powerplants while one plant had
to temporarily suspend operations due to fuel shortages.
       Maintain a public information program. The SECO plant sent out
staff to address local citizens groups such as the Lions' Club, Ladies
Garden
       Club, Kiwanis and others on a regular basis. In the first five
years they made presentations to over 10,000 people. This was especially
important
       for Dow Corning as chemical plants tend to be regarded as less
than perfect environmental stewards by the public. DeBlaay described
their
       efforts as being very "up-front" with the community.
       Agricultural residues don't "travel well," and require special
fuel handling systems. These modifications reduce the economic
attractiveness of
       these supplies.
       When purchasing fuel, the moisture content must be accounted for.
This is often done through a "moisture deduct" where payments are based
on
       the green ton and the payment is adjusted for the moisture
content. However, this often leads to bad feelings as suppliers feel the
plant is "taking
       money from them," so DeBlaay advises sampling shipments for
moisture and adjusting payments on the front end for "the BTUs that you
use."
       SECO staff have adjusted to staff reductions with efficiency
improvements. These include use of computerized mapping through global
       positioning systems (GPS), geographic information systems and
field computers.


Speaker Information

Terry DeBlaay is Fuel Supply Manager with Dow Corning Corporation. He is
actively engaged in fuel procurement for its 22 MW wood fired power
plant in Midland, Michigan. Mr. DeBlaay works on managing private forest
land to harvest, submitting bids on timber sales on state and federal
forests,
and developing forest management plans for subsequent regrowth of
forests.

He also oversees the urban/industrial waste wood program, and manages
the inventory and scheduling for the wood fuel. His professional
training is in
wildlife and forest management.

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Last updated on August 9, 1995.
This document is based on a presentation made at the Biomass Energy
Infrastructure Workshop in Madison, Wisconsin on June 6-7, 1994.

This was written by Andy Olsen, who also organized the workshop. To
contact Andy, send email to: AndyO@inxpress.net


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