POWER October 2010 - 46

TOP PLANTS
1. Tapping into Lake Michigan. This photo shows the water intake tunnel, located
below the lake bed. The tunnel directs cooling water drawn from Lake Michigan to the four
existing Oak Creek units and the new Elm Road Units 1 and 2 at the Oak Creek Power Plant.
The once-through cooling system is used to cool and condense steam from the steam turbines.
Courtesy: We Energies
emissions of particulates, SO2
, and the other
regulated emissions were tested to be considerably
lower than required by the project's
air permit. In the case of SO2
, carbon monoxide,
and many other regulated substances,
the emission rates were a fraction of required
permit levels. "
The two units use supercritical boilers that
operate at higher temperatures and pressures
when compared with conventional subcritical
plants. The corresponding steam conditions
allow the units to operate at higher thermal
efficiencies. In addition, the plant utilizes water
from Lake Michigan in a " once-through "
cooling system to cool and condense steam
from the steam turbine (Figure 1). The cold
heat sink allows the plant to extract the maximum
possible energy from the steam and
hence improves the plant's thermal efficiency.
(See " Deep Excavation Support Systems
Speed Plant Construction, " p. 74.)
The Elm Road expansion project includes
pulverized coal units was essential to the
plan's overall realization. The plan included
the objective of expanding or constructing
the needed generation at existing brownfield
sites, rather than at new, undisturbed greenfield
locations.
Keeping the Expansion Project
on Deadline
On June 29, 2005, construction of the two
new 615-MW units began. The expansion
units have become known to many as the
Elm Road units in order to distinguish them
from the existing four units at Oak Creek,
Metcalfe explained.
On February 2, 2010, the new Elm Road
Unit 1 passed all of its performance tests and
was placed into commercial service. Unit 1
was tested to be among the most efficient
plants of its type in the country.
Today, Bechtel Power Corp., the project's
engineering, procurement, and construction
contractor, is focusing its efforts on completing
the commissioning and testing of Unit 2.
The first fire on coal in the Unit 2 boiler was
achieved on July 8, and the generator was
synchronized to the grid for the first time on
July 16. Since then, the unit has operated at
up to 100% of its rated capacity.
As this story was being written, Unit 2
was shut down for a scheduled two-week
outage. Bechtel was using the time to address
punch list items and to remove start-up
equipment. The unit is expected to return to
service around the middle of September for
46
further tuning and a series of rigorous performance
tests.
" As with any two-unit plant, the second
unit benefits from the lessons learned on the
first, thus shortening the start-up and commissioning
schedule, " Metcalfe said. " The
guaranteed turnover date for Unit 2 is set for
November 28. We expect Bechtel to meet or
beat this completion date. "
It's also not unusual for new plants to experience
" teething difficulties " in the first
year or two of operation, according to Metcalfe.
He predicted that ultimately the units
will achieve an annual average equivalent
availability factor exceeding 85%.
We Power LLC, a subsidiary of Wisconsin
Energy, owns Unit 1 and is leasing the
energy output to We Energies. We Energies
is responsible for the operation and maintenance
of the unit. The leasing arrangement is
unique and was developed through enabling
legislation.
Overview of Elm Road Units 1 and 2
Both units, which burn Eastern coal, have
state-of-the-art air quality control equipment,
including selective catalytic reactors to remove
nitrogen oxides, baghouse filters to remove
particulate matter (ash in the exhaust gas),
scrubbers to remove sulfur dioxide (SO2
), and
a wet electrostatic precipitator to remove sulfuric
acid and very fine particulates.
" Unit 1's emission tests were completed
in January 2010, and the results are considered
world class, " Metcalfe said. " Actual
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a redesigned coal-handling facility. Approximately
17 miles of new rail line and 2.5 miles
of conveyors were installed. The old system
required the locomotives to be decoupled
from the rail cars and for the rail cars to be
broken into three separate strings to enable
unloading through a rotating car dumper. In
addition, the old system required each car to
be manually positioned through painstaking,
highly skilled operations.
In contrast, the new system allows the
locomotive to pull the entire string of up
to 130 rail cars through a new rotating car
dumper. Once the first car is in position, an
" indexer " automatically positions each subsequent
car by pulling the entire string of
cars through the dumper. After the unloading
is completed, a new rail loop allows the
locomotive to proceed directly off the site
with the empty cars, without having to reverse
its direction. The coal-handling system
includes an indoor storage facility that
has the capacity to store three days' worth
of coal for the older and newer units at the
site when running at full load. This storage
facility is fully automated, allowing coal to
be remotely unloaded and recovered from a
central control room.
Future Directions
" As we finish construction of the two new
units at Oak Creek, we are increasingly focused
on completing a more than $800 million
air quality control system upgrade of
the existing, older OCPP units. We are also
developing renewable energy projects to balance
our portfolio and meet the renewable
portfolio standards for the state of Wisconsin, "
Patulski said. ■
-Angela Neville, JD, is POWER's
senior editor.
POWER | October 2010

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POWER October 2010

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