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Steam-only plants destined for the Smithsonian
PACESETTING PLANTS, Class of 2007/2008
81
Class of 2007/2008
C
onnecticuts electric-pow-
er infrastructure is in
bad shape. Basically, in-
state generating capabil-
ity is insufficient to satisfy native
demand; power-delivery infra-
structure is inadequate and gen-
erally old. Not a pretty picture.
The state began to tackle the issue
with passage of the 2005 Energy
Independence Act. One of its provi-
sions is a grant program aimed at
reducing the $500 million in federal-
ly mandated congestion charges paid
by Connecticut residents in 2005.
The congestion charge, a line item
on every electric bill, is reduced in
accordance with the states progress
in resolving the problem.
Grants are available to
help large users get off
the grid by subsidizing the
capital cost of new onsite
generation. They also are
available to private produc-
ers with generation assets
that agree to supply power
to the grid when called
uponso-called standby or
backup power.
Opportunity.
Pratt &
Whitneys 1100-acre Mid-
dletown campus, which
operates around the clock,
was an ideal location for a combined
heat and power (CHP) facility. It had
a large thermal load and purchased
all the electricity required to support
3500 employees in 34 major build-
ings. The company had known for
years that the days were numbered
for large powerhouses producing only
thermal energy. Back-of-the-enve-
lope calculations confirmed that.
However, before any design work
and budgeting are done for a new
central energy facility it makes good
sense to audit energy use and imple-
ment conservation strategies that
offer a good return on the invest-
ment made. This way demand will
be optimized and the CHP
plant, when designed, will
not be oversized. The consid-
erable resources of United
Technologies Corp, P&Ws
parent, helped here. Recall
that UTC also owns Car-
rier Corp, which has a group
in its Building Systems &
Services unit specializing in
energy management.
Ward Strosser, manager,
Gregory Hester, PE, engineering
development manager, and others
associated within the Carrier Strate-
gic Partnerships Group in the North-
east region, began investigating how
energy was used on the P&W Middle-
town campus back in the late 1990s.
Conservation projects implemented
over the years based on comprehen-
sive audits include lighting upgrades,
installation of digital control systems
to optimize operation of ventilation
and illumination systems, retrofit
of variable-speed drives on pumps
and air-handling units, efficiency
upgrades to the steam distribution
and condensate return systems, etc.
First phase of the Middletown
energy conservation effort included
the replacement in 1999 of an age-
ing chilled-water plant. The new
integrated HVAC system combined
efficient chillers using non-ozone-
depleting refrigerants and system
automation for optimized
performance and energy
savings. Three 1200-ton
electric-motor-driven cen-
trifugal chillers and three
800-ton absorption chillers
were installedthe absorp-
tion units for load shedding.
That project earned more
than $150,000 in efficiency
rebates from the local util-
ity. P&Ws investment was
returned in less than five years on
energy savings alone.
Major drivers for this project were
Pratts goal of a 40% reduction in
operating costs by 2002 and UTCs
corporate-wide environmental initia-
tives.
Fast forward to 2004:
It was time to review power-
house operations once again.
What had changed since the
last review? Heres what
Mark Kopera, manager of
energy services operations
for P&W, told the editors:
n
The cost of boiler repairs
a n d m a i n t e n a n c e h a d
increased because the units
were getting older. Tube
replacements and economiz-
er repairs were frequently
necessary.
n
The existing steam system was
inefficient and oversized for actual
thermal demand. This, plus the
increasing cost of fuel, put a big
dent in the operating budget.
n
Operating expenses were lower
at P&Ws East Hartford facility
where an FT8-3 gas-turbine-based
cogen plant had been installed in
the early 1990s.
The $64 question:
What was the
low-cost option for providing steam to
the Middletown campus based on the
latest information available?
The answer: CHP. It would gain
corporate support quickly when Mid-
dletowns proposal for a 7.5-MW facil-
Middletown Campus Powerhouse
Middletown, Ct
Pratt & Whitney
Steam-only plants destined
for the Smithsonian
Aqueous ammonia storage
1. A 2+-mi-long, 6-in.-diam pipeline was installed to
move gas from the main line to the pressure-reduction and
cleanup skid at the powerhouse
Kopera 82
COMBINED CYCLE JOURNAL, Fourth Quarter 2007
Class of 2007/2008
ity was approved under the states
Capital Grant for Customer-Side
Distributed Generation Resources
program and awarded a $450/kW
upfront incentive. Delivery charges
for gas transported by the LDC
(local distribution company)
from the city gate to the plant
also are paid for
under this pro-
gram.
An incentive
of this magni-
tude certainly
is a project initiatorbut there are
strings. For example, the plant
must run at an average capacity fac-
tor of 85% during hours when grid
demand peaks and during the months
of June through September and
December and January. Thats cer-
tainly not a stress-free requirement.
Plus, P&W had to post a bond to guar-
antee that the plant would operate for
five years.
The CHP plant,
which was
commissioned early in 2008, pro-
vides about two-thirds of Middle-
towns summer peak electric demand
and nearly 100% of its steam load.
Approximately eight months a year it
satisfies the sites total electrical and
thermal requirements.
Another benefit of the project is
that it is helping Middletown achieve
a corporate goal aimed at reducing
carbon emissions. The background:
In 2006, UTC began planning a
corporate-wide initiative to reduce
greenhouse-gas (GHG) emissions.
During the previous 10 years, it had
focused on conservation of energy
and water use and on reducing the
amount of hazardous waste that UTC
produced.
In 2007, the corporation announced
a four-year goal to reduce GHG by
12%, using 2006 annual emissions
as the baseline. Middletown is UTCs
second-largest site and improvements
in powerplant operations alone
including the installation of the CHP
systemwere credited with reduc-
ing its GHG footprint by the 12%
required.
A significant part of the emissions
reduction was achieved by install-
ing two new low-emissions packaged
boilers from Rentech Boiler Systems
Inc, Abilene, and by switching from
No. 6 boiler fuel to natural gas and
0.5%-sulfur distillate. The new boil-
ers replaced an ageing unit capable
of producing up to about 150,000 lb/
hr that was demolished.
Electrical connection.
P&W
owns the 115/13.8-kV substation
serving the Middletown facility. Two
115-kV feeders from different sources
assure affordable reliability. Pratt

Turbine (three stages)
Compressor
(14 stages)
2. Taurus 70, the
heart of the CHP
system, produces 7.5
MW at ISO conditions
3. Chiller in air inlet structure uses
nominal 55F well water for cooling



Gas
flow
Gas-turbine
package
Sampling ports
SCR module
Expansion joint
Evaporator 1
Ammonia injection grid
Catalyst hoist/monorail
Monitoring
platform
Stack
CEMS, EPA
monitoring
ports
Economizer
Evaporator 2
4. Unfired heat-recovery steam generator pro-
duces 30,000 lb/hr of 200-psig steam when the GT
operates at full load. Photo at right shows manifold
that serves the SCRs ammonia injection grid PACESETTING PLANTS, Class of 2007/2008
83
Class of 2007/2008
cannot export power to the grid, but
it can island if necessary. While it
will not be able to satisfy 100% of
Middletowns electrical demand in
the unlikely event both feeders are
lost, critical powerhouse electric ser-
vice will be maintained. Total ther-
mal demand could be met if the grid
were to fail. Today there is no black-
start capability installed onsite.
The difference between site elec-
trical demand and onsite generation
is supplied by the grid. A third-par-
ty power marketer, licensed by the
state, purchases electricity for P&W.
Gas is bought from the LDC under an
interruptible contract.
Kopera says that senior manage-
ment thinks of the plant as provid-
ing energy independence. In effect,
Middletown now has the opportunity
to take advantage of market condi-
tions, provided it satisfies the provi-
sions of the states grant program.
To illustrate: Should the price of grid
power drop below P&Ws cost of pro-
duction, Middletown could buy power
and use one packaged boiler to sat-
isfy site thermal requirements.
Project/equipme