POWER September 2014 - 33

TOP PLANTS
1. Delicate operation. One of the Solar Taurus gas turbines is rigged into the narrow
confines of the new NYU cogen plant during construction. Courtesy: Vanderweil Power Group
bined with a low-pressure system in the Atlantic,
causing it to re-intensify and turn sharply to
the northeast-directly toward the New York-
New Jersey area. The eye of the storm made
landfall the following night about five miles
north of Atlantic City. That location meant the
New York City area to the north would take
much of the brunt of the northwestern edge of
the hurricane, where the strongest winds and
storm surge would be.
Though the 48 deaths and widespread
flooding across the city dominated the headlines,
the damage to the city's electric grid was
also immense (ConEd would later estimate
its repair costs at $450 million). Power was
out south of 35th Street in Lower Manhattan
for nearly a week, and it would be more than
a month before electricity was completely restored
across the city. Most of New York had
no choice but to wait for repairs.
At NYU, it was a different story.
On the night of Oct. 29th, Sandy's storm
5.6-MW Solar Taurus 60S dual-fuel gas turbines.
Each turbine drives a generator, and
each feeds its own HRSG supplied by Nebraska
Boilers.
The 600-psi steam from the HRSGs is put
to a variety of uses. First, it's passed through
a 2.4-MW steam turbine generator. The exhaust
from the turbine is then fed to another
pair of heat exchangers to make high-temperature
hot water and, when necessary, to a
2,400-ton steam-driven chiller to make cold
water for air conditioning. The entire system
is run from a fully digital control system that
maintains peak performance and efficiency
that approaches 80% in normal operation.
The plant is capable of producing 20,000 lb/
hr of steam, and when an auxiliary boiler is
fired up, it can produce another 40,000 lb/hr.
The connection to the Consolidated Edison
(ConEd) grid was upgraded with a new
transformer vault and six new transformer
banks. The system includes protective relays
to insulate the microgrid from fluctuations in
the utility grid when necessary.
Though the new system doesn't cover the
entire campus, it supplies power and heat to
much more of it than the old one. Twenty-six
buildings now get electricity from the system,
while 37 get their heating from it and 26
get chilled water for cooling. The system is
normally linked to the ConEd grid in a synchronous
interconnection, and power flows
back and forth as the campus's loads change.
But it is also capable of disconnecting and
going into island mode, powering the campus
on its own.
NYU announced when the plant was complete
that it was projected to save the university
around $5 million to $8 million a year in
September 2014 | POWER
energy-related costs. The new cogen system
would emit 23% lower carbon emissions,
while NOx and particulate emissions were
projected to drop 68% compared to the old
fuel oil-fired plant.
The project even gave NYU the opportunity
to give that part of the community a facelift.
Because the old plaza above the plant
had to be completely removed as part of construction,
a new community park was built as
part of the job. The once-generic sidewalks
outside the Courant Institute were turned into
a park-like setting with extensive seating and
gardens filled with native plants (shown in the
header photo). All in all, the project seemed a
highly worthwhile investment.
But the system's real value was yet to
show itself.
Going It Alone
In the fall of 2012, New York City had not
taken a hit from a full-strength hurricane in
more than 25 years. And though there had
been a few near-misses throughout the 20th
century, not since the Long Island Express
hurricane of 1938 had the city seen the sort
of widespread deaths and destruction associated
with major storms such as Hurricanes
Katrina and Andrew.
The system that would become Hurricane
Sandy formed in the Caribbean Sea south of
Jamaica in mid-October. It reached hurricane
status on October 24, and over the next few
days, moved north across Jamaica, Cuba, and
the Bahamas, before turning east into the Atlantic.
Though it had killed at least 60 people
(mostly in Haiti) by this point, it appeared to
be ready to dissipate.
On October 28, however, the storm comwww.powermag.com
surge
came over the banks of the East River
and took out ConEd's 14th Street substation.
When the transformers at the substation
exploded-a blast that was visible for
miles-voltages throughout Manhattan began
dropping rapidly, and the NYU microgrid
that had been drawing small amounts of
power from the grid suddenly began sending
dangerous amounts of it out. The protective
relays automatically tripped, disconnecting
from ConEd and putting the microgrid into
island mode as the rest of Lower Manhattan
went dark.
Suddenly finding themselves the sole
source of power and heat for much of the university
put the cogen plant staff under considerable
stress, since the safety net normally
provided by the ConEd grid was now gone.
The powered portion of the campus rapidly
became an oasis for staff, students, and surrounding
community members without electricity;
later, it became a command center for
emergency workers throughout Manhattan as
the city struggled to recover.
Under such circumstances, normal working
hours went out the window, and the engineers
simply did whatever had to be done to
keep things running smoothly-which they
did. " Essential utilities provided by the NYU
microgrid were consistently supplied for the
duration of the Sandy event with no interruptions
to key NYU facilities, " John Bradley,
NYU's assistant vice president of technical
services told POWER.
For demonstrating the efficiency and reliability
gains possible with modern cogeneration
and an associated microgrid, NYU's
system is named a POWER Top Plant. ■
-Thomas W. Overton, JD is a POWER
associate editor (@thomas_overton,
@POWERmagazine).
33
http://www.powermag.com
POWER September 2014

Table of Contents for the Digital Edition of POWER September 2014
