Document ID: EPA-HQ-OW-2008-0667-0018
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-11-05T05:00Z

Site Visit Report

	East River Generating Station

	801 East 14th Street

	New York, NY 10009

April 15, 2008

Background and Objectives

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.  East River Generating
Station (East River) was selected for a site visit due to its use of
fine mesh traveling screens and large intake flows.

Facility Description

East River is located on a 3.5 acre site on the eastern side of lower
Manhattan in New York City.  The facility is owned by Consolidated
Edison (Con Edison) and employs approximately 240 workers.  East River
began operations in 1927 and withdraws cooling water from the East
River.

Facility representatives started that the facility’s NPDES permit
(NY0005126) was renewed in the summer of 2007.  East River discharges
via a north and south outlet tunnel both of which are located north of
the intake.  East River primarily discharges through the South tunnel
and only discharges water associated with cable cooling via its North
tunnel.

Electricity Generation and Transmission

East River currently operates 4 generating units with a combined
generating capacity of 600 MW.  However, aside from generating
electricity, the facility is a primary source of steam used to heat
nearby buildings, thereby reducing the amount of electricity generated. 
The facility produces approximately 5.5 million pounds of steam per hour
and also serves as a gateway for transporting steam between the uptown
and downtown areas.

Units 1 and 2 began operations in 1927 and have since been repowered as
cogeneration units with a gas turbine.  Units 6 and 7 (built in 1951 and
1955, respectively) are dual fuel cycling units that typically run
during the day and may frequently change operating modes between
generating steam and electricity.  Unit 6 has a nameplate capacity of
130 MW, but typically generates approximately 75 MW due to the lost heat
from generating and transmitting steam.  Unit 6 also provides backup
steam to Units 1 and 2 and has a very high utilization rate (typically
greater than 90%).  Unit 7 was constructed as a baseload generating unit
(nameplate rating of 180 MW) that operates at approximately 70% capacity
in the winter as a steam generator and at approximately 50% capacity in
the summer as an electricity producer.

Each unit has a scheduled 2 weeks outage in the spring and fall, with a
major overhaul approximately every 6 years that can last as long as 6-8
months. The facility is located in a “load pocket,” with limited
infrastructure to generate and transmit electricity to nearby users.

Con Edison owns the switchyard.

Cooling Water Intake Structure

Unit 6 has two circulators with design flow of 59,200 gpm each.  Unit 7
also has two circulators with design flow of 69,000 gpm each. Cable
cooling design flow is 2670 gpm.  East River operates one cooling water
intake structure with a design intake flow of 371.5 million gallons per
day (MGD).  The facility’s average flow typically approaches the DIF
from May to September.

The intake structure is 150 feet long and 30 feet wide, with the river
depth at approximately 30 feet.  It is separated into 8 intake bays, but
only 4 of the bays are currently open to the river.  Bay 4 has a
crossflow opening that connects it with the other bays, even when the
circulating pumps are not operating for that bay.  This allows the
facility to enlarge the effective size of its intake structure and
reduce its intake velocity.  Initial estimates by the facility showed
that constructing a similar crossflow opening in one additional intake
bay would be sufficient to meet the 0.5 ft/sec threshold for impingement
requirements in the Phase II rule.  Facility representatives also noted
that the intake velocity across the face of the screen may not be
uniformly 0.5 ft/sec across the entire screen; achieving this level of
flow regulation may be exceedingly expensive.

The shoreline intake structure consists of bar racks (with 4” spacing)
and dual flow traveling screens with 1/8” smooth wire mesh a debris
return in Bay 4,5,6,and 7.  Each screen has a capacity of 90,000 gpm at
low water level.  These screens were installed in 1989 as an upgrade to
the previous configuration.  The screens are cleaned by a spray wash
into a single return trough; facility representatives noted that debris
is a constant challenge, especially plastic bags.  The return trough
discharges near the main outfall for the facility.  The river is
approximately 30 feet deep at the intake structure.

Of the original nine circulating inlet water pipes (each 6 ft in
diameter), East River currently only uses 2 pipes.  All of the pipes are
buried under 8 to 15 feet of concrete.

The facility retired Unit 5 in 1994 and has been granted a commensurate
flow reduction towards meeting impingement and entrainment requirements.

Facility representatives stated that the design intake velocity has not
been calculated, but that they have initially used the intake velocity
at the nearby Arthur Kill plant (0.56 ft/sec at mid-tide). 
Facility-specific velocity measurements will be conducted this summer. 
Facility representatives stated that the tides (approximately 11 ft
between high and low tide) have minimal effect on the intake velocity,
but can have a substantial effect on the thermal plume.

No biocides are in use at the facility.  The intake structure is cleaned
by divers once per year.  There is significant siltation in the intake
screen and bays due to the sediment load in the waterbody and near
constant disturbance by tides and vessel traffic.  However, the facility
does not dredge since the sediment would quickly re-accumulate.

Impingement and Entrainment Information

Facility representatives noted that the East River ecosystem is rapidly
recovering.  The facility conducted biological monitoring in 1993, 2004,
and 2005/2006; facility representatives stated that this would be
sufficient data to conduct the analyses required in a Comprehensive
Demonstration Study.  Impingement and entrainment reductions were
calculated based on a simple count and a flow-weighted analysis,
respectively.  During the most recent study, the facility collected,
categorized and enumerated impingement and entrainment once a week.  For
impingement, the facility analyzed all organisms; for entrainment, the
facility analyzed organisms that passed through 0.365 mm net.  East
River then used the sampling results to construct a model that predicts
the I&E reductions of age-1 equivalent organisms associated with fine
mesh for I (69%) and flow reduction opportunities for E (31%).  The
study considered seasonal and diel variations.  Facility representatives
indicated diel variations were minimal.  East River indicated that three
species dominated the sampling and that the species composition in the
more recent sampling was somewhat different than in 1993, but the total
count was approximately the same.  Facility representatives also stated
that the peak spawning period in the East River generally overlaps with
periods of peak power generation. 

Cooling Tower Feasibility

The facility is located in a highly urban, densely developed
environment.  The facility is located adjacent to the East River, with
its intake screenhouse located on the eastern side of FDR Drive.  The
facility’s substation and oil storage tanks are to the south, as are
other city-owned buildings and low-income housing.  To the west are
medium-rise residential buildings.  To the north are two recreational
baseball fields on property owned by Con Edison used by the city parks
department; however, facility representatives stated that the scarcity
of parkland in the city and political pressure has effectively
eliminated any possibility of alternate uses for the space.  Facility
representatives stated that there is no readily available adjacent land
for purchase and that land prices are increasing as the area is
recognized as an “up and coming” neighborhood.

NY Department of Environmental Conservation (NYDEC) noted that the space
required for wet cooling towers is approximately the same size as the
ballfields, but has agreed that closed cycle cooling is not feasible at
the site, due to issues with sufficient space to build the towers and
the impacts from the plume.  Facility representatives also noted that
they would expect heavy resistance to permits for the plume from a
cooling tower, as well as noise and visual impacts.  Dry cooling was
also briefly considered by NYDEC, but would require an even larger
parcel of land.

Additional Information

In lieu of installing closed cycle cooling, East River will propose a
suite of technologies as BTA after conducting a series of analyses
required by its current permit (i.e., alternative technology analysis). 
The permit contains many of the same requirements as the now-suspended
Phase II rule (including a performance range for reducing impingement
and entrainment).  The facility has already submitted a study that
examines closed cycle cooling, seasonal flow reductions, the current
intake technology and other information.  A subsequent study evaluated
alternative intake technologies.  Because Con Edison considers fine mesh
traveling screens to be a promising technology for this site, East River
will also be conducting technology pilot tests using screens 6 and 7
this summer, including a 1 mm mesh traveling screen.  Once the
technology studies are complete, a construction and implementation
schedule will be developed.

Facility representatives stated that restoration was not considered a
viable alternative under the Phase II rule, as the facility believed it
could meet the performance standards.  Additionally, there are few sites
nearby that would be suitable as restoration projects.

Given the age of the facility, it is not completely clear what
infrastructure is located underground.  Facility representatives were
not sure about the location of all water, steam, and other utility
pipes, particularly beneath the substation and other areas of the
facility.

The condenser for Unit 6 was re-tubed in 2000.  Unit 7 was re-tubed in
1989.

Attachments

Attachment A		List of Attendees

Attachment B		Aerial Photo

Attachment C		PowerPoint slideshow #1, April 15, 2008

Attachment D		Site Visit Photos

Attachment A--List of Attendees

Paul Shriner, EPA

Jan Matuszko, EPA

Kelly Meadows, Tetra Tech

Mike Kessler, Con Edison

Ming Lau, Con Edison

Jack Steenbeek, Con Edison

Tim Ellis, Con Edison 

Danielle Bacskay, Con Edison

Attachment B—East River Aerial Photo

Please see DCN 10-6506B accompanying this document.

Attachment C--PowerPoint slideshow #1, April 15, 2008

Please see DCN 10-6506A accompanying this document.

Attachment D--Site Visit Photos

Please see DCNs 10-6506C-F accompanying this document.

 Facility representatives noted that, depending on the direction and
strength of the tides, some intake water may be withdrawn from Long
Island Sound or the Hudson River.

 A fifth unit was retired in 1994.

 Bays 1, 2, 3 and 8 are blocked off with bulkheads.

 During outages, a second set of trash racks are put in place.

 The buckets on the screens are not of the modified/Ristroph design.

 The original traveling screens were oriented parallel to the river
flow.  The dual flow screens were designed to fit into the existing
screenwells.

 FDR Drive was built in the 1930s and bisects the facility’s property.
 Access to the pumphouse (and all piping) is via underground tunnels.

 The facility stores kerosene as an emergency fuel.  It also stores #6
fuel oil for Units 6 and 7, as well as the nearby South Steam Station,
which has 5 dual fuel boilers that supply steam to the city and operate
approximately 50% of the time.

 Facility representatives stated that it is not uncommon for Con Edison
property to be used by the city or local residents for recreational or
open space; previous efforts by Con Edison to develop these lands have
resulted in substantial resistance from residents and city staff.

 Under existing operational conditions, there have been instances of
leaked steam forming ice on nearby roads in winter.

 Variable speed pumps were excluded from further study due to concerns
over head loss across the intake structure.

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