MEMORANDUM

Tetra Tech, Inc.

10306 Eaton Place, Suite 340

Fairfax, VA 22030

phone	703-385-6000

fax	703-385-6007

DATE: 		March 5, 2010

TO:			316(b) Record

	

FROM:		Kelly Meadows, Tetra Tech

SUBJECT:	Winnetka Power Plant teleconference notes

The Environmental Protection Agency (EPA) is in the process of
developing 316(b) cooling water intake structure requirements that
reflect the best technology available (BTA) for minimizing adverse
environmental impact for all existing power plants and manufacturing
facilities.  As part of this process, EPA staff is visiting electric
generators and manufacturers to better understand the cooling water
intake structure (CWIS) technologies in use at facilities, including the
site-specific characteristics of each facility and how these affect the
selection and performance of CWIS technologies.  EPA is also visiting
facilities to better understand cooling water use and specific issues or
technologies that can affect 316(b) compliance.

The Winnetka Power Plant (Winnetka) was identified as a site of interest
due to its low design intake flow (DIF) without using closed-cycle
cooling.  Unfortunately, due to scheduling conflicts, EPA is unable to
visit the facility.  However, Tetra Tech staff was able to speak to
facility superintendant Jeffrey Pietka on July 29, 2009 and March 5,
2010 to gather more information about the facility.  A summary of the
discussion is presented below.

Facility Information

Winnetka Power Plant is located in the Village of Winnetka, a northern
suburb of Chicago with a population of about 15,000.  It withdraws
once-through cooling water from Lake Michigan and began operations in
1900.  The facility is owned and operated by the municipality and has
three natural gas-fired steam electric generating units and two diesel
combustion units with a total capacity of 32 MW.  The capacity
utilization rate for the facility is approximately 5%.  The facility
currently has no plans for repowering or adding new generating units.

The facility is located on a small site on the waterfront and sits
between public and private beaches, parks, and a boat ramp, and is in
close proximity to hundreds of high-value homes.

The facility uses a shoreline intake structure with an intake canal and
coarse-mesh vertical traveling screens.  The DIF for the facility is
15.7 million gallons per day and when operating, the actual intake flow
is 5.2 mgd.

The facility has not conducted any impingement or entrainment studies.

Despite the low intake flows (and subsequently smaller cooling tower
footprint), installing a close-cycle cooling system would likely be
difficult at Winnetka due to space constraints; the small site does not
offer significant space and the close proximity of residences would make
siting and permitting a closed-cycle system very difficult.

 Winnetka is one of only 25 Phase III power plants with a DIF below 50
million gallons per day (mgd) that does not employ closed-cycle cooling.
 In this case, the low flow is simply due to the small size of the
generating unit.

 All five units utilize lake water for cooling.  The combustion units
were installed in 1979 and no major renovations (e.g., boiler
replacement, etc.) have been completed since that time.

 Using aerial photos, it is estimated that the site is no more than 5
acres, with existing structures, forest, and beach occupying most of the
area.  There are also a half dozen homes within 200 feet of the
facility.

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