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					 UTC POWER FUEL CELL OPERATION AT
THE MOHEGAN SUN CASINO AND RESORT

                     January 2007




  A report submitted to the Connecticut Department of
              Environmental Protection
                           By

   The Mohegan Tribe and UTC Power Corporation




                           1
                                  Table of Contents



Section   Title                                                                                              Page


A         Mohegan Environmental Policy and History .................................... 3

B         Executive Summary ............................................................................. 4

C         Fuel Cell Project Planning .................................................................. 6

D         Technology Description ...................................................................... 12

E         Overcoming Barriers .......................................................................... 19

F         Interconnections for Heat Recovery.................................................. 19

G         Operator Training .............................................................................. 20

H         Installation Requirements .................................................................. 21

I         Operation ..............................................................................................23

J         Performance ........................................................................................ 24

K         Lessons Learned.................................................................................. 27

L         Conclusions.......................................................................................... 27

App A     CARB 07 Testing................................................................................. 29

App B     Selected Sections of the Service Manual ........................................... 32

App C     Letter from NEWMOA ...................................................................... 40




                                                  2
A. MOHEGAN ENVIRONMENTAL POLICY AND HISTORY

THE MEMORANDUM OF UNDERSTANDING (MOU) BETWEEN MOHEGAN TRIBE
AND CONNECTICUT DEPARTMENT OF ENVIRONMENTAL PROTECTION (CTDEP)

Under the Clean Air Act (CAA) the State of Connecticut is obligated to develop a State
Implementation Plan (SIP). The SIP provides for implementation, maintenance and
enforcement of the national primary and secondary air quality standards for each air
quality region within the state. The memorandum of understanding (MOU) between the
Connecticut Department of Environmental Protection (CTDEP) and the Mohegan Indian
Tribe (hereinafter “the Tribe”) concerns the adoption of Connecticut’s SIP by the Tribe
and its commitment to ensure that their operational commercial enterprises on the
Reservation, particularly the Mohegan Sun, do not negatively affect the State’s ability to
achieve the National Ambient Air Quality Standards (NAAQS). The Tribe agreed to
offset car and bus emissions resulting from patron transportation activities, with an
exemption granted for employee car trips made to work. These offsets shall be made on
a one-to-one basis and shall be provided in the form of emission reduction credits which
meet EPA and DEP standards.

THE TRADING AGREEMENT AND ORDER NO.8143 BETWEEN MOHEGAN
TRIBE AND CONNECTICUT DEP

The Tribe agreed that it is in the public interest that the Tribe work cooperatively to
improve the air quality within the State of Connecticut and that the use of emission
reduction trading will achieve this result in a timely and cost-effective manner. On
August 7, 1995, the Tribe agreed to offset volatile organic compounds (VOC’s) and
nitrogen oxides (NOx) emissions resulting from patron transportation activity. Approved
emission reduction credits (ERC) are defined as those which the Commissioner has
provided written authorization for use in meeting the requirements of the attainment
demonstration in accordance with the CAA Section 182(c)(2)(A). The CTDEP and the
Tribe agreed to a set of emission factors for determining the ERC’s to be acquired and
used as offsets needed for operation of the facility. This trading agreement and Order No.
8143 were submitted to EPA for incorporation into the SIP.

Therefore, in 1996 in accordance with the MOU and Trading Agreement and Order No.
8143, the Tribe began purchasing emission reduction credits (surplus reductions by
others) at market value. In September 2000, the Tribe proposed to substitute these annual
payments for the capital investment in environmental supplemental projects which would
promote improved air quality for all the citizens of the state for a portion of the required
ERC offsets in an amount equal to the cost of the project divided by $1000/ton for NOx
ERCs and $2500/ton for VOC ERC’s.

As a result, the CTDEP approved a $2,434,360 Mohegan fuel cell technology purchase
for a demonstration and public outreach program. Fuel cell performance results were to
be published along with other environmental projects to encourage the public and
industry to make similar improvements and promote awareness of the need for clean
energy alternatives. This project has been very successful in promoting clean energy and
provided credit offsets through the summer ozone season of 2003. Subsequently, a list of


                                             3
$7.1 million in potential energy conservation projects was submitted in May of 2005. In
March of 2006, a “Fuel Cell Technology Demonstration Report” was submitted to
CTDEP detailing actual expenses paid by the Tribe for each of these completed and
proposed projects and approval of $4.2 million was granted which offset emissions
through the end of 2006. On another front, this project has been a very successful
collaboration between the Mohegan Tribe and UTC Power.

In April of 2006, the Tribe submitted patron and vehicle counts to CTDEP and
Connecticut Department of Transportation (CTDOT) to recalculate emission estimates
using updated Mobile 6.2 modeling parameters. This resulted in the recalculated number
of tons of volatile organic compounds (VOC’s) and NOx for May through Sept. 2005.
The VOC tonnage was calculated as 140, the NOx tonnage was calculated as 259. When
these tonnage numbers are multiplied by the appropriate dollar figures a total of
$609,000/year was derived. This number divided by the remaining approved projects
amount of $2.9M yields vehicle emission offsets of about 4.8 years for 2007-2011.

“The Mohegan Tribe has maintained a Spiritual relationship with Turtle Island (Mother
Earth). The Mohegan Tribe over the past decade has operated a very successful
casino. That success has given the tribe opportunities for innovative resources to land
management and development. Rather than being a burden to Turtle Island, the Tribe
has implemented unique and trend-setting ways to provide ‘environmental protection’” –
Edward Sarabia, Connecticut Department of Environmental Protection recently quoted
and this fuel cell project was an excellent start to realizing the goal of Mohegan Tribe.

B. EXECUTIVE SUMMARY

Self sufficiency is a concept that has long held special meaning for many Native
American people. The long term goal of Mohegans is to become as self sufficient from
the electrical grid as possible. Five years ago the fuel cell installation along with state of
the art boilers running on natural gas were considered an innovative hybrid energy
system. In the last five years, the fuel cells have generated 16,115 MWhr of electricity
and saved the Tribe $1,247,324 in electrical charges at the Mohegan Tribal Utility
Authority rates. This means they exceeded their original goal of 3,000 MWhr. If the
same amount of electricity and heat were purchased by conventional means, it would
have resulted in about 10,985 tons of CO2 and 19.67 tons of NOx emitted into the
atmosphere. Now that the fuel cells have been in operation for the last five years, other
projects with sustainability in mind are being considered.

In 1996, the Tribal Council formally adopted a Pollution Prevention resolution. The fuel
cell project is consistent with this resolution as it produces: reduced emissions, potential
grid-independent supply of electricity and heat, monitoring data generation and reliability
for uninterrupted power supply. The Mohegan Tribal Council recognized that fuel cell
technology is extremely clean, quiet and reliable with negligible production of sulfur,
nitrogen oxides, volatile organic compounds (VOC’s) and particulate matter (PM). In
addition, fuel cell operation generates fewer carbon dioxide emissions than conventional
fossil fuel plants. These advantages are explained in more detail in Section D entitled
“Technology Description.” Appendix A shows that the PureCell system meets the



                                              4
strictest air emissions standards of any state in the U.S., namely California’s CARB 2007.
To offset carbon dioxide emissions from the fuel cells, the Tribe voluntarily planted 100
acres of fast growing klinki trees in Costa Rica at a cost of $121,000 under the Reforest
the Tropics initiative to sequester an equivalent amount of CO2 by photosynthesis.

One of the first environmental energy conservation projects to offset vehicular emissions
was the purchase and installation of the UTC Power PureCell™ Model 200 fuel cells in
2002. UTC Power’s long experience in installing and commissioning fuel cells for power
and cogeneration applications involving thermal recovery made the process simpler than
one would have anticipated. The ease of installation and operation cannot be overstated.

The fuel cells proved to be very reliable by being available more than 97 percent of the
time as shown in Table 1. The efficiency was very high, in the 85-90% range because of
the full utilization of the heat in the application. To date (12/31/2006), the value of the
electricity produced by the fuel cells is $1,247,324 as reported in Table 2. The exhaust
heat generated during this period of time is 79,896 MMBtu and was used for thermal
needs of the facilities as explained later. This accounted for an additional $1,022,463 in
savings over this period of operation. Fuel cells operating on natural gas are classified as
a Class I Renewable Energy source in Connecticut and therefore are eligible for
Renewable Energy Credits (REC’s) that are an additional source of revenue generation
for the project. To date, Mohegan Sun has received about $276,810 in REC’s payments.
The cost of the fuel cells (equipment, installation, and maintenance) was $2,848,360.
                    Table 1: Performance (March 2002 to December 2006)

Total MWhrs Produced                                                   16,115 MWhrs
Heat Produced                                                          79,896 MMBtu
Availability                                                               97-98%
Electrical Efficiency                                                    43 – 34 %
Overall Efficiency                                                       ~ 85-90 %

                    Table 2: Cost Savings (March 2002 to December 2006)

Electric Savings*                                                    $1,247,324.83
Thermal Savings*                                                     $1,022,463.32
Cost (equipment, installation, and maintenance)                        $2,848,360
Cost of fuel*                                                          $1,667,114
Operational savings**                                                   $188,674
Revenue from REC’s                                                      $276,810
* At Tribal Utility rates.
** Operational savings is (Electric savings + Thermal savings) – (cost of fuel & maintenance)

For a typical customer who is paying commercial electric rates in Connecticut, the
savings would have been greater. Using December 2006 commercial rates for the
electricity and natural gas, the estimated savings would be $2,157,215 as shown in Table
3. The REC’s would be an additional revenue source to add to the total savings.




                                              5
               Table 3: Estimated Savings at current commercial rates

Electric Savings*                                                      $2,417,305
Thermal Savings*                                                       $1,098,570
Cost (equipment, installation, and maintenance)                        $2,848,360
Cost of fuel*                                                          $1,358,661
Operational savings**                                                  $2,157,215
* At December 2006 commercial rates
** Operational savings is (Electric savings + Thermal savings) – (cost of fuel & maintenance)

In September of 2005, the U.S. Environmental Protection Agency (USEPA) and the
Department of Energy (DOE) presented the Mohegan Tribe with the 2005 Energy Star
CHP (Combined Heat and Power) Award based on the fuel cells, successful waste heat
recovery system which supplies the Central Plant boilers with make-up water and the
Earth Casino with domestic hot water. The CHP system operated at about 85%
efficiency.

On a quarterly basis, UTC Power is providing the Mohegan Tribe with performance
summaries for both FC-1 (SN9255) and FC-2 (SN9264) which measure operating hours,
available hours, availability, electrical output and natural gas consumption. Johnson
Controls is providing actual monthly cost savings in electrical and thermal energies
where gas consumption costs are subtracted to provide a net cost savings.

The Mohegan fuel cell demonstration project is a very successful project that represents a
substantial commitment in time and financial resources by the Tribe. It exceeded the
goal of demonstrating that fuel cells using hydrogen as fuel can be applied to a practical
application in Connecticut. More than 1000 visitors including representatives of
numerous American Indian Tribes, state and federal agencies (i.e. NEWMOA on June 14,
2006), NASA, DOE, university students, industry and other interested parties have
viewed the fuel cell demonstration project, which also includes PEM cell technology
provided by a grant from the Connecticut Clean Energy Fund (CCEF) and demonstrated
by Proton Energy Systems located in Wallingford, Conn.

C. FUEL CELL PROJECT PLANNING

In July of 2000, the Mohegan Tribe proposed a Mohegan Fuel Cell Research, Monitoring
and Educational Program. This program was to be further developed and implemented
by the Fuel Cell Workgroup derived from the Mohegan Pollution Prevention Team.
The Mohegan Tribe evaluated various low-emission and sustainable energy technologies
for Reservation use. They found that fuel cell power plants have a logical role in the
tribe’s Integrated Energy Management Plan because of their reliability, fuel efficiency,
low emissions of nitrogen and sulfur oxides, low scheduled maintenance and quality of
power supplied.

The Mohegan electrical and heat demand is continuous as the hotel and casino operate
24/7 without any closure or shutdown. Therefore, reliable, continuous power is a main




                                            6
concern for the MTGA Engineering Department, which operates the Central Plant
boilers, chillers, emergency generators and fuel cells.

The Mohegan Fuel Cell Monitoring Team was to gather technical information on the
operation, fuel use, electrical and thermal output and air emissions. This data was to be
made available to the Connecticut Department of Environmental Protection, other Native
American tribes, interested engineers, university students, educators, environmental
agencies and groups and the general public. As part of the ongoing educational program
and on request, the Mohegan Tribe hosts scheduled visitors to the fuel cell facility. The
visitors are provided with updated presentations on the overall energy efficiency,
electrical and thermal output and efficiencies, electrical and thermal cost savings, cost
effectiveness, air emissions (1999 vs. 2005) and the major reasoning behind the Tribe’s
purchase of the fuel cells including a discussion of the numerous energy conservation
projects done by the Engineering, Transportation, Development and Public Safety
departments. In addition to the presentation on the UTC Power fuel cells, a presentation
on the upgraded Proton Exchange Membrane (PEM) fuel cells is provided by Proton
Energy Systems and a demonstration of their power is provided in the classroom. In
addition, there are three computers in the back of the classroom which schematically
reflect the operation of the PEM fuel cells (computer located closest to the viewing
glass), FC-1 (middle computer) and FC-2 (computer farthest away from the viewing
glass).

The following project tasks will be discussed in some detail below: location selection,
utilities integration, fuel cell purchase, building/site work, fuel cell unit install, education
center, performance testing, emission analysis, power analysis.

C.1 Location Selection: The building which houses the fuel cells was the former
Mohegan fire truck garage. This location was chosen because of the existing overhead
doors, high ceilings and close proximity to the boilers and domestic hot water supply
lines. This location supports the efficient use of hot water from the fuel cell operation, as
well as convenient linkage to the emergency switchgear for an uninterruptible power
supply. However, the floor had to be load tested to be sure that it could support the
weight of the two fuel cells. After passing the load test, the floor was sealed for
containment of any leakage. The building had to be modified to support the education
center installation as that area was previously used for Facilities Department offices.

A new elevator capable of carrying passengers was installed at the end of the corridor in
place of the former pallet lift. The elevator machine room which supports the unit
controller was relocated to the other side of the elevator shaft to accommodate the
installation of the education center as well.

Interface connections are quite simple for the PureCell™ system. There are 5 fluid
interface connections. An additional interface was connected for heat recovery.
Connecting these fluid systems results in seven interface connections at the power
module and two at the cooling module. The five (5) fluid systems are as follows:

        1. Natural Gas Supply
        2. Nitrogen Supply


                                               7
       3. Ancillary Cooling
       4. Heat Recovery 2 low grade; 2 high-grade (optional)
       5. Make-Up Water Supply

The electrical interfaces were also fairly simple. There are 4 basic electrical interfaces in
the standard grid connect configuration. A grid independent operating feature is available
as an option but was not chosen for this application. Additionally, there are four optional
control signal interfaces.

The area outside the building was paved and a concrete pad was added to support the
installation of two (2) dry coolers (one per fuel cell) for waste heat rejection in lieu of a
conventional CUP water condenser system due to the long piping run from the condenser
water mains to the fuel cell location. This method of cooling the fuel cells was approved
as less expensive than using the Central Plant’s cooling towers, which would have




            Figure 1 - Dry Coolers for heat rejection with fence enclosure

required individual interfacing heat exchanger between the central system and each fuel
cell and the addition of expansion tanks. The Central Plant’s cooling tower system had
no emergency back-up power so in the event of a power failure, each fuel cell would shut
down due to overheating if the flow was not restored within 30 seconds. The advantage
of a central condenser system utilizing water towers is that the system is quieter and
provides better fuel cell condenser water recovery. However, in this application, almost
all of the available heat is being recovered and very little cooling is required.

There is an ancillary cooling system installed between the PureCell™ Model 200 fuel
cell units and the dry coolers described above. This piping system is filled with
propylene glycol / de-ionized (DI) water mixture for freeze protection in northern
climates.




                                              8
C.2 Utilities Integration: A water quality analysis had to be performed by MTGA staff
to evaluate the use of a reverse osmosis unit. Instead of a reverse osmosis system, two
(2) de-ionized (DI) tanks in series are utilized with a carbon pre-filter for removal of
chlorine from the Tribal Utility Authority (TUA) water distribution system. The pre-
filter protects the DI tank resin from chlorine degradation. To protect the fuel cell
systems from resin fines, a cartridge filter is placed after the DI tanks.

The low-grade heat recovery system is not a recirculation type. It provides preheated
domestic hot water at 140 degrees F to a Patterson-Kelly hot water system serving the
Earth Casino restrooms and kitchens. The pumps were to cycle on and off in response to
the pressure demands in the system. A double-walled heat exchanger has been provided
inside the fuel cell units to prevent glycol coolant contact with domestic hot water.
However, early on it was discovered that 30 psi pressure drops were experienced prior to
the completion of the domestic water loop. Subsequently, a pressure-reducing valve
station was installed by TUA at the end of Crow Hill Road and this lessened the pressure
fluctuations to the 4-5 psi range.

The high-grade heat recovery system is configured to deliver heat at 250 degrees F and is
utilized in the Central Plant as boiler condensate pre-heat for the boiler. Internal controls
within the fuel cells allow for the interfacing, sharing, switching and alternating of heat
rejection between low-grade heat recovery, high-grade heat recovery and the auxiliary
cooling modules. In addition to pressure control of pumps, relief valves are provided.
Low- and high-grade flows are balanced by valves at pump locations and at fuel cell heat
exchangers in conjunction with instrumentation (i.e. gauges and thermometers).

The fuel cells are configured for “grid-connected” mode of operation. Utility grid
protection is part of the standard system. The standard 480-volt grid connection is three
(3)-wire. The neutral is not connected in “grid-connect-only” mode of operation. The
neutral of the fuel cells wye output transformer is left un-terminated to either the user or
system (grid) neutral. The primary reason for not terminating the transformer neutral is
to avoid potential excessive transformer neutral currents induced by non-linear grid
neutral currents.

Therefore the fuel cells go into the “idle mode” when there is a loss of utility power.
They will remain off-line until the electric generator starts. To obtain total grid
independence requires purchasing the IFC Site Management System and providing UPS
power to externally powered ventilation fans, controls, pumps, etc. Cristino Associates,
Inc. the Tribal Utility Authority’s (TUA) electrical consulting engineer provided review
for the overall design, master planning and analysis for how the electrical connection was
configured.

C.3 Utilities Future Planning: The Engineering Department’s initial plans included the
exploration of heating the T building with waste heat from the fuel cells by steam to hot
water heat exchanger or water-to-water heat exchanger from the high-grade heat recovery
system in each fuel cell. However, a closer analysis of the heat usage determined that all
of the available heat from the fuel cells is being utilized already and hence this plan was
abandoned.



                                              9
C.4 Fuel Cell Purchase: In 2001 the Mohegan Fuel Cell Team (Figure 2) was
established by the Tribe. After reviewing a Solid Oxide Fuel Cell (SOFC) CHP system
made by Westinghouse, also natural gas fueled, the decision was made to purchase
PureCell™ Model 200 units on June 21, 2001. The units were purchased with the
optional low noise four fan air cooling modules and they were sited outside the building
within a fenced-in area. The two units were shipped and delivered to the Mohegan
Central Plant during the week of January 21, 2002. They were installed and successfully
started on March 13 and 14 and achieved 200 KW each on the same day.




                           Figure 2 - Mohegan Fuel Cell Team

C.5 Building/Site Work: Flack and Kurtz, Inc. of New York City provided all
mechanical and electrical engineering services including the interconnection of fuel cell
power and waste heat output with the new and existing infrastructure. In addition, they
acted as general contractor to coordinate the activities of all the other consultants required
to accommodate the fuel cell program in connection with the installation of the two units.
All architectural, structural and site civil design services were provided by the other
consultants. The design area they had to work with was 2080 square feet. The design
included provisions for the future installation of up to four additional fuel cell units. A
visitor viewing area approximately 15’ X 10’ was included as part of the Mohegan
Energy, Environment, Economics, Demonstration Center. The architects hired by Flack
and Kurtz, Inc. were Kohn Pedersen Fox (KPF) Associates, PC from New York City.
KPF provided services for the schematic design, design development, contract documents
and construction administration phases under the provisions, terms and conditions of the
Mohegan Sun Phase II Expansion Project. The project scope included: 1) design of the
viewing area including all wall, ceiling and floor finishes, door(s) and viewing glass, 2)
assisting in the general coordination of the room, 3) indication of duct enclosures for


                                             10
ductwork passing up through the second floor to the roof, 4) fences for exterior-mounted
cooling modules, 5) prepare contract documents for filing with Tribal Authorities and
construction administration, 6) CAD drawings of the existing area for modification.

Desimone Consulting Engineers, PLLC provided the following structural engineering
services: 1) the foundation for the fuel cells and cooling modules, 2) the framing for the
slab openings, and 3) trolley beam design for five-ton hoist. Cristino Associates, Inc.
provided fuel cell installation and integration based on the Flack and Kurtz, MEP design
for the fuel cell installation.

C.6 Fuel Cell Unit Installation: Supplemental rigging instructions were issued by UTC
Power for power plant installation inside a building. Ideal support locations for ground
handling using pad rollers are under the lift points. First American Mechanical rented a
crane and set the units in place, installed natural gas meters, cut the concrete floor,
installed the duct work and curbs, repaired the roof after penetrations were made to
accommodate the ductwork exhaust, fire stopped all penetrations and installed labeling
on all piping. Native Sons installed all required data and phone lines.

Analysis of the natural gas supply and make-up water supply were requested by UTC
Power. The natural gas supply is checked to make sure it is within specification and this
information is used to provide tuning data for input to the power plant controller for
optimum operation. The gas is checked for sulfur, methane, higher hydrocarbon
constituents, oxygen, carbon dioxide and nitrogen levels. The sulfur level in the fuel has
a direct impact on the life of the PureCell fuel processing system. The size of the gas
meters was another consideration. Each meter was sized at 3000 SCFH as each fuel cell
consumes an average of 2050 SCFH. The common pressure regulator was sized for 6000
SCFH.

The make-up water analysis allows UTC Power to make a pretreatment system
recommendation. The analysis included turbidity, conductivity, dissolved oxygen, pH,
silica content and total dissolved solids. At a minimum, the use of a mixed resin bed
bottle in the make-up stream is recommended.

The first start-up of a PureCell™ Model 200 fuel cell unit requires a minimum of two
weeks and a field engineer from UTC Power assists with the initial start-up of the unit.
Therefore, UTC Power requires a minimum of one month notice for scheduling a field
engineer. In addition, the utilities connections must be available at the fuel cell location
for: electrical (480v power), natural gas (regulator regulated at 3000 SCFH), make-up
water line and mixed resin bed bottle, nitrogen bottles full and operational (24 required
for start-up), phone line for modem and one for human use. UTC Power issues a “First
Start Requirements” document and a fuel cell “Customer Check List” to make sure
nothing is overlooked.

C.7 Education Center: The main barriers to the growth of fuel cells as a clean energy
source are the reluctance of potential customers to use fuel cells partly because of the
lack of firsthand experience in operating fuel cells, safety concerns for hydrogen as a
fuel, and the high capital cost of the technology. This reluctance to adopt new
technologies is a universal barrier to implementation of fuel cells in industry, universities


                                             11
and colleges, hospitals, other institutional uses such as prisons and remote locations
where normal grid power is unavailable or cost prohibitive.

Guests visiting the Mohegan Energy, Environment, Economics and Education Center are
provided with three different power point presentations detailing: 1) why and how the
Mohegan Tribe got involved with purchasing fuel cells, other renewable energies on the
reservation and energy conservation projects installed or in progress, 2) UTC Power’s
global perspective on why fuel cells are important to the environment and 3) PEM fuel
cell technology contrasted with UTC Power units, hydrogen safety factors and the
applications for PEM cell technology with an emphasis on providing electrical power in
very remote locations. The PEM fuel cells are demonstrated on-site by using them to
power the laptop and projector used to show the power point presentations and by
running small appliances (hair dryer) with the energy generated by the PEM cells.

In addition, the three computers located at the back of the room provide operational
schematics for demonstration purposes. Visitors are provided with either lunch or snacks
and beverages. See Appendix C for a letter from the Deputy Director of Northeast Waste
Management Official’s Association (NEWMOA) regarding their visit to the Education
Center on June 14, 2006.

C.8 Performance Analysis: Johnson Controls has independent meters for the electrical
and thermal outputs. This metering instrumentation automatically reports to the facility
building automation system (Metasys). Once the data is collected in metasys, it is stored
and trend data is compiled into the electrical/thermal net cost savings monthly.

C.9 Emissions Monitoring: Johnson Controls has CO2 monitoring devices located in the
ceiling above the fuel cells. These devices are set to audibly alarm at a concentration of
1000 ppm. The Engineering Department receives notification automatically and they will
take corrective action by venting the fuel cell room with outside air. There are sensors in
the ceiling that will also shut off the fuel cells in the event that CO2 levels exceeds pre-set
limits. Johnson Controls also monitors the hydrogen concentration with monitoring
devices located in the ceiling as well. This device is set to audibly alarm at 5% hydrogen
in the fuel cell room atmosphere and the same notification sequence is triggered as
described above.

D. Technology Description

D.1 Principle of Operation of Fuel Cells

A fuel cell is an electrochemical device that is composed of an anode (a negative
electrode that provides electrons), an electrolyte in the center, and a cathode (a positive
electrode that accepts electrons) – shown in Figure 3.

A fuel cell can operate on different kinds of fuels including hydrogen, anaerobic digester
gas, propane, etc. In the case of the UTC Power PureCell™ Model 200 fuel cell system,
hydrogen-rich gas is formed from natural gas and serves as the fuel for the power plant.
As hydrogen flows into the fuel cell anode, platinum coating on the anode helps separate



                                              12
the hydrogen atoms into protons (hydrogen ions) and electrons. The electrolyte in the
center (phosphoric acid in the case of the PureCell™1 fuel cell system) allows only the
protons to pass through this electrolyte to the cathode side of the fuel cell. The electrons
cannot pass through this electrolyte and, therefore must flow through an external circuit
in the form of electric current. This current can power an electric load. As oxygen flows
into the fuel cell cathode, another platinum coating helps the oxygen, protons, and
electrons combine to produce pure water and heat. Individual fuel cells can then be
combined into a fuel cell ‘stack’.




                   Fuel                                                  Oxygen
                (Hydrogen)                                                (Air)

                                 Electrons                  Electrons




                                                 H+
                                             (hydrogen
                                                ions)          C
                                      A                        A
                                      N                        T
                                      O                        H
                                      D                                         Waste
                                                               O                heat
                                      E                        D
                                             Electrolyte       E
               Waste
               heat                                                     Water




                                              Platinum
                                              catalyst

                        Figure 3: Fuel Cell Operation
D.2 The PureCell™ System

The PureCell™ Model 200 system is a complete factory-assembled and tested system
producing 200 kW of electrical power. Figure 4 is a schematic representation of the
product in operation. The system is fueled by pipeline-quality natural gas. It is converted
into a hydrogen-rich gas by an internal fuel processor. The heart of the system is the
PAFC fuel cell stack, where an electrochemical reaction occurs between hydrogen and
oxygen from air to generate electricity, heat, and water. Unlike conventional combustion
technologies, there are no moving parts in the fuel cell, and the lack of combustion results
in extremely low levels of chemical emissions of nitrogen oxides, sulfur dioxide, and
particulate matter. An inverter-based power conditioning system converts the direct


1
    PureCell™ is a trademark of UTC Power Corporation



                                                       13
current (DC) power generated in the fuel cell stack to alternating current (AC) power for
supplying the electrical grid or customer loads.

         Fuel Processor
      Converts natural gas
        fuel to hydrogen




   Fuel Input                                                                      Electric Output:
   • 2,050 SCFH Natural Gas                                                        • 200 kW, 480 V, 60 Hz




        Fuel Cell Stack                                                         Power Conditioner
     Generates DC electricity                                                 Converts DC power to
         from hydrogen                                                        high quality AC power
                                    Internal heat exchanger provides:
                                        • 885,000 BTU/hr @ 140F
                                                    OR
                           • 435,000 BTU/hr @ 250F & 450,000 BTU/hr @ 140F


                                   Figure 4: PureCell™ System

Figure 5 below shows the internals of the PureCell™ system.
                           Condenser                                  Air Supply         Steam
           Fuel Reformer               Cell Stack Assembly             Blower            Drum




                                                    810f13C                               WCN15165




             ILS                         Power Conditioning Electrical    Thermal Management
                                             System        Control System      System


                           Figure 5 - Internals of the PureCell™ system

The system takes in fuel and air and not only produces electricity but a large amount of
waste heat that can be utilized in applications requiring heating.


          FUEL                                                     ELECTRICITY
                                   POWER                           HEAT
          AIR                      PLANT
                                                                   EXHAUST


                      Figure 6: Fuel Cell System Inputs and Outputs


                                                              14
D.3 Advantages of cogeneration over conventional generation:

Compared to the conventional generation where the grid supplies electricity, on-site
cogeneration provided by fuel cells offers significant advantages in terms of efficiency
which can be clearly seen from Figure 7.




    Fuel Cell




   Figure 7: Comparison of Fuel Cell CHP with Conventional Power Generation

Another advantage over the conventional powerplant model is in the area of emissions.
Figure 8 shows the emissions of the electric grid in the United States and the comparison
between coal, petroleum, and natural gas-fired powerplants. In all cases, we can see that
emissions are significantly high, particularly for the coal-fired power plants. In
comparison, the emissions from the PureCell system are orders of magnitude lower as
shown in Figure 9. This figure also compares the emissions with that of a natural gas
generator. Again, the PureCell system’s emissions advantage is significant. The PureCell
system has been certified to meet the toughest emissions standards in the country
(California Air Resource Board’s CARB 07 standards). It also has been granted an air
permitting exemption from the Connecticut Department of Environmental Protection due
to the ultra-low emissions profile.


                                            15
          Greenhouse Gas Reduction
          (CO 2lbm/MWh)                                                                        Sulfur Dioxide
          (CO lbm/MWh)
             2                                                                                 Nitrogen Oxides
            2,089 2,089                                                  17
                                                                         17
                                                                                               (lbm/MWh)
                          1,753     1,753
                                                                                         12
                                                                                        12
                                        1,237     1,237


                                                                              6.5
                                                                              6.5
                                                                 570
                                                                                                          3.6
                                                                                                          3.6
                                                                                              2.8
                                                                                              2.8
                                                                                                      0
                                                                   0
           Coal Coal Petroleum Gas
                Petroleum Gas                                       Coal Petroleum Gas
                                                              PureCell
                      (                                                , 1995)
      Ref: US DOE EIA Electricity Generation & Environmental Externalities
                                                                               ,
           Ref: US DOE EIA (Electricity Generation & Environmental Externalities1995)



                 Figure 8: Emission from central power plants in the U.S.




                 Figure 9: Emissions comparison with the PureCell system

D.4 Comparison with other on-site power solutions:

Reciprocating engines, microturbines, gas turbines and high-temperature fuel cells are
potential alternatives to the PureCell system. The following general points can be made
about these solutions.

•   Reciprocating engines dominate the on-site market. Capital costs are lower than that
    of the PureCell system. However, the fuel cell has many significant advantages
    including significantly lower emissions (as seen in the previous section), higher
    overall system efficiencies, and lower noise and vibration profile which make it very
    suitable for siting in high people traffic areas.



                                                          16
•   As far as gas turbines are concerned, achieving electrical efficiencies and cost targets
    in the sub MW class is difficult.
•   Microturbines are relatively new to the DG market. Their disadvantage is that their
    efficiencies are relatively low.
•   The high-temperature fuel cell (molten carbonate fuel cell often referred to as MCFC)
    has higher electrical efficiency but lower overall efficiency in comparison.

Table 2 compares the efficiencies and emissions of these technologies.

                                                 Table 2

                               PureCell                      Gas                                MCFC
                                        Recips                             Microturbines
                                System                     Turbines                             fuel cell
 Performance (@ rated)
 Elec. Eff (% LHV, Avg)              37         38 2           24 3                 27               42 6
                                                   2               3
 Total Eff (% LHV)*                 > 85        80             79                   80               63 6
 Emissions (lb/MWhr)
    NOx                            0.019 1     0.17 2       <0.0454               0.24 5            0.07 6
                                         1           2
    VOC                            0.001       0.38                            < 0.18 THC           0.02 6
                                         1           2                4                5
    CO                             0.002       2.74          <0.04                 1.4               0.1 6
                                                                    4
 Emissions (vs. CARB07)              yes        No            yes                   No              yes 6
* Assuming full heat utilization
 1
   Source: Test Report of Emissions from a PureCell Fuel Cell Juvenile Training School, Rex Technical
   Services, LLC, C-11-05, CJTS Report Addendum, October, 2002.
 2
   Source: Gas-Fired Distributed Energy Resource Technology Characterizations, NREL Report (2003)
 3
   Values reported are averages of various commercial products surveyed within 400 kW to 2 MW range.
 4
   Rated power emissions reported for Kawasaki GPB15X gas turbines where the CHP efficiency is equal
   to 77% Kawasaki reports the GPB15X gas turbine can meet CARB07 NOx emissions when gas turbine
   is operate at CHP efficiency greater than 60%.
 5
   Based on CARB test protocol (weighted performance average)
 6
   Source: Fuel Cell Energy web-site. Total Efficiency value is a calculation based on the reported heat
   availability of 300,000 Btu/hr.

Wind and solar are also clean energy technologies and Table 3 below summarizes the
comparison to the PureCell system in terms of avoided CO2 and NOx.




                                                    17
                                                                         Table 3

                                                              Annual Avoided CO2                          Annual Avoided NOx
                                                                  Emissions                                   Emissions
                                                                           Equivalent acres                           Equivalent
                                                             Tons             of forest
                                                                                        1               Tons        number of cars
                                                                                                                                   2




            PureCellTM 200
                                          3
                                                               782                 164                   2.80               147

                      Wind
                                                               318                 67                    0.57               30
               (25% Utilization)

                     Solar                                                                                                  17
                                                               178                 37                    0.32
               (14% Utilization)


 1. Each acre of forest assumed to absorb 1.3 tons Carbon/acre/year (Ref: International Panel on Climate Change)
 2. Each car assumed to generate 38 lbm/NOx/year (Ref: US EPA)
 3. Assumes full heat utilization

D.4. 1 Noise Emissions:

Another important criterion is noise pollution. The PureCell system has a very low noise
profile compared with other on-site power technologies such as gas turbines and
reciprocating engines. Figure 10 shows that the system-generated noise level is only
about 60 dbA (@ 30 ft) and is therefore well-suited for indoor operations. Another
distinct advantage of the PureCell system is that the vibrations associated with the
PureCell in operation are negligibly small in comparison. The low noise and vibration
features of the PureCell system become especially important as the trend towards
urbanization continues. It can easily be installed in high people traffic areas without the
need for any kind of ear protection equipment.

          dB

               Shotgun, Handgun
               Rifle, Fireworks at 3 ft
               Rock music peak, Artillery fire at 500 ft

               Airplane taking off, Rock singer screaming in microphone
               Air raid siren, Percussion section, Stock car race
               Chain saw, Ambulance siren, Jet plane at airport runway

               Leaf blower, Car horn, Symphony concert
               Diesel truck, Jackhammer, Boom box
                                                                                                      is 60 dBA @ 30 ft *
               Tractor, Food processor, Screaming child

               Noisy restaurant, Alarm clock, Acoustic guitar at 1 ft
               Freeway traffic, Piano music, Vacuum cleaner

               Normal conversation, Clothes dryer
               Refrigerator, Average home, Large office
               Background noise in a library, Quiet residential area
               Quiet office
               Rustling leaves, Whispering at 5 ft

               Normal breathing, Quiet recording studio

               Softest sound a person can hear



                                                           * Or 54 dBA w/low noise cooling module option

                                                     Figure 10: Low Noise Profile


                                                                           18
E. OVERCOMING BARRIERS TO USING NON-TRADITIONAL
TECHNOLOGIES

The initial Fuel Cell Team was comprised of the following Mohegan Departments:
Environmental Protection, Finance, Legal, Utility Authority, Engineering, Public Safety,
Planning and Development and approval was sought from the Tribal Council when
necessary. In addition, the Tribe utilized numerous consultants on the fuel cell project as
they had experience in preparing and presenting peer-reviewed research reports and
papers necessary to justify the in-depth engineering and scientific study of the fuel cells
as required by CTDEP.

An early concern was a service contract with UTC Power including the replacement of
the cell stack in operational year 5-7, which in 2001 dollars was estimated to cost
$300,000 per unit. In 2006 dollars, each cell stack replacement cost has escalated. So far
the electrical efficiencies we are experiencing on both units does not warrant replacement
of the cell stack at this time. Another issue at the onset of the service contract was the
waste that was generated by the fuel cells during maintenance activities and how that was
to be handled for disposal. An agreement was reached for UTC Power to containerize
and take off-site the small amount of hazardous waste generated during routine
maintenance activities.

More recently, in 2005 a meeting was held with UTC Power and Johnson Controls to
facilitate the electrical/thermal monitoring requirements mandated by the agreement with
CTDEP for the fuel cell project. UTC Power provided electrical monitoring data
obtained from their RADAR data management system to Johnson Controls to generate
spreadsheets dated January 2003, 2004, 2005. Now, starting with January 2006, the data
is remotely accessed by Johnson Controls systems. This data presented in kilowatts on
the electrical side and in British Thermal Units (BTUs) on the thermal side is the basis for
the cost savings shown in Table 1 on page 5.

F. HEAT RECOVERY
The fuel cell has two separate interfaces for heat recovery (Figure 11). The high-grade
heat interface is designed to provide heat to systems with higher return temperatures; for
example, space heating systems with 190 F supply and 170 F return, which can supply
heat at up to as much as 250 F. The low-grade interface is designed for heating systems
with low inlet or return temperatures, such as domestic hot water systems with an 80 F
inlet temperature and 140 F supply temperature.

At Mohegan Sun the two fuel cells provide heat recovery in parallel from both the low
and high-grade interfaces, as shown in the figure below.

The low-grade heat recovery heat exchangers in the fuel cells are double walled for use
with potable water. At Mohegan Sun the low-grade heat is used to preheat the cold water
supply to the domestic hot water heating system. The Mohegan Sun system is a once
through type (not recirculating) so that cold water is always supplied to the fuel cells and
this maximizes heat recovery. The cold water makeup to this system is basically at below



                                             19
ground temperatures. Downstream from the fuel cells, the pre-heated water is delivered to
the Patterson-Kelly hot water heating plant for supplemental heat addition as required.
The Patterson-Kelly system serves the Earth Casino restrooms and kitchens.

The high-grade heat recovery system in the fuel cells is used to pre-heat the condensate
return from the steam plant. A portion of the condensate return before the de-aerator is
pumped to the fuel cells for heat addition. The internal fuel cells controls were tuned to
limit the supply temperature back to the de-aerator inlet to less than 206 F to avoid
flashing in the de-aerator. Any heat not used by this high-grade system is captured in the
fuel cells and made available as additional heat in the low-grade heat recovery system.

                                                                       Mechanical Plant
                                          Condensate return
                                               185 F                                      Condensate supply
                                                                                               205 F
   Fuel Cell (FC-1)
    Power Module                                                         Deaerator                             Boiler
                                       Pump                                                                   Make-up
                                                                       High Grade Heat Recovery for
                                                                       Condensate Pre-heat



                                                                          DHW makeup
                                                                           35F to 75 F

                                                              Pump
   Fuel Cell (FC-2)
    Power Module
                                                         Low Grade Heat Recovery for
                                                         Once Thru DHW Heating

                                                DHW 110F to 140 F
                                                supply to Patterson-
                                                Kelly DHW heaters           To Earth
                                                                             Casino




                               Figure 11: Heat Recovery


G. OPERATOR TRAINING
All Engineering Department operators within the Central Plant were trained on the
operation and maintenance of the fuel cells. The typical training session is about a week
long and it goes through the information in the service manual in detail and is
complemented with actual power plant hands-on instruction. As far as actual maintenance
of the 2 units at Mohegan Sun, UTC Power provides all the required service on both units
under a five-year service contract. The units are provided with numerous maintenance
tasks on the following intervals: quarterly, semi-annually, annually, two-year, three-year
and five-year.




                                              20
H. INSTALLATION REQUIREMENTS
The installation was a standard installation for the most part and the requirements are laid
out in the standard installation manual provided by UTC Power. Some salient points of
this standard installation are captured in the bullet points below:

•   The Power Module is designed for side entry for both the mechanical and electrical
    interconnections and may be set on any level foundation with sufficient structural
    support. The Cooling Module should be secured to the Cooling Module foundation.
    See Figure 12 below.




                   Figure 12: Foundation Example – Concrete Slab

•   The site must be in a well-drained area and the area surrounding the power plant must
    be free of combustible materials and adequate clearances provided around the air
    supply, ventilation, and exhaust openings. Generally, an 8-foot accessibility area
    around the power plant is adequate. A basic installation layout with mechanical and
    electrical interfaces is shown - in Figure 13. Additional interfaces are required in
    applications where the high-grade heat option or grid-independent electrical option
    are selected.




                                            21
                  Figure 13: Standard Mechanical/Electrical Layout

•   A dedicated telephone line must be provided to permit communication with the power
    plant data and control system. Connected to the modem of the fuel cell, the line must
    be capable of direct dial out (to an 800 number in the United States)
•   A second voice line is recommended for use during on-site maintenance and trouble-
    shooting
•   The site design should include provisions to facilitate delivery and change of nitrogen
    bottles that will be replaced periodically and water treatment resin/charcoal bottles
•   Gas and water analysis of the local natural gas and domestic cold water supply also
    should be completed
•   Other requirements include two 55-gallon drums, a liquid transfer pump and hoses,
    etc. More details are available in the Installation Manual

There was a change from the standard procedure required due to elevated piping between
Power Modules and Air Cooling Modules. The Mohegan Sun fuel cell installation
required a modification to accommodate the elevated 2" copper supply and return piping
installed between each Power Module (PM) and its corresponding Air Cooling Module
(ACM) . In a standard installation, the ACM and all interconnecting piping must be
installed lower than 8 feet from the base of the PM. Otherwise, the fluid in the piping will
be pumped out of the accumulator vent as shown in Figure 14. The system was converted
to a closed loop by removing the hose connection between the suction side of the internal
PM pump 830 and the accumulator. The accumulator hose connection interface was
plugged and the accumulator was retained to serve as a reservoir for any discharge of the
relief valve PSV800. A new bladder type expansion tank was installed external to the PM
and connected to the PM at pump 830 where the hose was removed. A pressure gauge


                                            22
and hose bib were provided in the new expansion tank piping in order to fill and
pressurize the system.
                                                                                                          New
                                                               Internal accumulator                     Expansion
       Fuel Cell Power Module
                                                               to remain in system                        Tank
                                                                                      vent
         Internal Pressure                                                                                                          Added to
                                                                                                                    P
         Relief Valve                                             ACC 840                                        pressure
                                                                                                                                  installation
         80 psig set point                                                                                       gauge
                                                   Plug
                                                                         Discard hose             hose bib for
                  PSV 800                          tank
                                                                         Add fitting, piping      system fill


            Ancillary Cooling
            System piping                            PMP 830




                                                                                                           Air Cooling Module
                                                                                                                 (not to scale)

                                 Expansion Tank Design Specifications
         System           Fluid Temperature, F          Pre Charge         Tank Volume, gallons         Supply and return piping from
     Volume, gallons       Cold            Hot        Pressure, psig      Acceptance     Total          Power Module to Air Cooling
          ~50          min. ambient        230             ~10                10         12.5          Module was installed higher than
                                                                                                         Power Module ACC840 vent
                                                                                                        necessitating a closed system.


      Figure 14: Mohegan Sun Fuel Cell Air Cooling Module Piping Modification

I. OPERATION

A detailed discussion of the standard startup procedures, shutdown instructions, normal
and emergency shutdown procedures, and normal monitoring operation are available in
the UTC Power Service Manual (Volume 1, Pages 2-91 to 2-97 and a copy of these pages
is attached to the end of this report for reference). Troubleshooting procedures are also
part of the standard service manual (Section 3). UTC Power tracks the status of all the
power plants using a daily status report. Every morning, each power plant is polled for
operating data. The power plant transmits the data, via telephone, to UTC Power’s
headquarters. Service personnel at UTC Power analyze the data and, when necessary,
will contact the applicable power plant people (owners, operators, service people) if
maintenance is necessary. Suggested parameters, if monitored periodically as
recommended, can give the operator a sense of the “health” of the power plant. With this
knowledge, major problems can be mitigated or avoided with the timely application of
preventive maintenance (instead of major overhaul). This can reduce the number of
planned and unplanned shutdowns, with the added benefit of improved power plant
reliability and longer service lives of major components, especially the cell stack
assembly.




                                                                        23
J. PERFORMANCE

J.1 Data Collection

Performance data trends for the fuel cell power plants are plotted in the graphs and tables
that follow. Data has been recorded at the frequency of at least one data set per day from
the time the fuel cells have been installed. Recorded data consists of nearly all
parameters utilized by the power plant controller, and is communicated through the
control system modem to the database at UTC Power.

This daily logging of controller data allows for a fairly accurate representation of power
plant gross availability, fuel flow and net power, as well as cumulative parameters such
as fuel use, power output and load hours, enabling calculated parameters such as
electrical efficiency to be determined.

J.2 Power Output and Availability

The first plot below shows Gross Availability calculated on a monthly basis, defined
simply as fuel cell load hours accrued per month divided by calendar hours per month.
The fuel cell load hours accumulate at all times while the power plant is running. In
addition, no calendar time has been omitted in the calculation, such as during planned
down times for maintenance. The units are seen to quite often run at 100% Gross
Availability; indeed, lifetime average Gross Availability ranges from 96.6 to 97.6 for the
2 Fuel Cells (Figure 15). A further indicator of the fuel cell performance reliability is the
trend of electrical power. The plot of Net Kilowatt Output Power (Figure 16) shows
nearly all data is the full-rated power of 200 kW for both fuel cells since startup in early
2002.

The only significant outages were not directly related to the fuel cells themselves. One
extended outage was a result of a decision by the operator to shut the units down during
the time the outside area was being paved with asphalt to prevent the fumes from the
asphalt curing from being ingested into the fuel cells. The other outage was caused by
the shutdown of the room exhaust fans due to power failures associated with failure of
the local grid, which powered the fans. The system was subsequently modified so that
the fans are now powered directly from the fuel cell output. Other outages in 2006
involved a leak on FC-1 where the unit was down for four consecutive days from
February 27 through March 2 and then again on March 15. FC-2 had a bad thermal
control valve on May 10, 2006 on the high-grade hot water recovery system side and a
steam leak was discovered at the same time. In September of 2006, fuel cell # 1 (FC-1)
was powered back to 150 kW due to the heat exchanger requiring maintenance and
cleaning. In October, FC-1 had a natural gas leak in the reformer leading to reformer
failure and subsequent replacement under the service contract. In November, this unit
experienced a water leak that was immediately rectified by UTC Power. Currently the
unit is back on line and fully operational.




                                             24
                                                                  GROSS POWER AVAILABILITY

                           100


                            90


                            80
                                                    FUEL CELL #1
                            70
 MONTHLY AVAILABILITY, %




                                                    FUEL CELL #2

                            60


                            50                      FUEL CELL #1 LIFETIME AVERAGE AVAILABILITY = 96.6 %
                                                    FUEL CELL #2 LIFETIME AVERAGE AVAILABILITY = 97.6 %
                            40


                            30


                            20


                            10


                             0
                                 May-02




                                 May-03




                                 May-04




                                 May-05




                                 May-06
                                 Mar-02




                                 Nov-02



                                 Mar-03




                                 Nov-03



                                 Mar-04




                                 Nov-04



                                 Mar-05




                                 Nov-05



                                 Mar-06
                                 Aug-02
                                 Sep-02




                                 Aug-03
                                 Sep-03




                                 Apr-04



                                 Aug-04
                                 Sep-04




                                 Aug-05
                                 Sep-05




                                 Aug-06
                                 Apr-02

                                 Jun-02
                                  Jul-02


                                 Oct-02

                                 Dec-02
                                 Jan-03
                                 Feb-03

                                 Apr-03

                                 Jun-03
                                  Jul-03


                                 Oct-03

                                 Dec-03
                                 Jan-04
                                 Feb-04



                                 Jun-04
                                  Jul-04


                                 Oct-04

                                 Dec-04
                                 Jan-05
                                 Feb-05

                                 Apr-05

                                 Jun-05
                                  Jul-05


                                 Oct-05

                                 Dec-05
                                 Jan-06
                                 Feb-06

                                 Apr-06

                                 Jun-06
                                  Jul-06
                                                                                   DATE


                                                                      FUEL CELL POWER HISTORY
                                                                    NET AC KW ELECTRICAL OUTPUT


                           200



                           175



                           150


                                                                                                       FUEL CELL #1
                           125
                                                                                                       FUEL CELL #2
  KWACNET




                           100



                           75



                           50



                           25



                            0
                           1-Mar-02   31-Aug-02   2-Mar-03   1-Sep-03   2-Mar-04     1-Sep-04   3-Mar-05   2-Sep-05   4-Mar-06   3-Sep-06
                                                                                   DATE




                                          Figures 15 & 16: Gross availability and net power output

J.3 Electrical and Overall Efficiency

The historical trend of Electrical Efficiency is also exemplary for both fuel cells.
Electrical Efficiency is defined as Net Electrical Energy Output / Fuel Energy Input to the



                                                                                      25
fuel cell. The fuel cell data system measures cumulative Power Output in Kilowatt-hrs
and Fuel Use in standard cubic feet. Thus,

Electrical Efficiency = (Net Kilowatt-hrs * 3413 * 100 ) / ( Fuel Use * LHV),

where LHV is the Lower Heating Value in Btu/Cubic Feet, and 3413 is the conversion
from kilowatt-hrs to Btus. This relation can be utilized over any time period, and is
plotted here on a bi-weekly rolling average basis.

Electrical Efficiency has varied from over 43% at inception to 34.5% at about 39,000
hours of load time, based on a lower heating value of 925 Btu/cu ft (Figure 18). The
downward trend with time is primarily due to the inherent voltage decay trend of the fuel
cell stacks. These levels meet or exceed the lifetime average typically quoted for the
fuel cells of 37%. Note: Fuel Cell #1 efficiency had recently fallen off but since the
writing off this report, a maintenance action was executed and the problem has since been
corrected.

Overall Combined Heat and Power Efficiency can also be determined when low-grade
and high-grade heat recovery is measured and included in the efficiency calculation:

Overall CHP Efficiency is calculated as follows:

(Net Kilowatt-hrs * 3413 * 100 + Heat Recovered ) / (Fuel Use * LHV),

where the Heat Recovered is measured in cumulative Btu’s over a time period.

The Overall CHP efficiency has recently been calculated at 85% to 88%, based on heat
recovery data measured from a separate data system. This efficiency also meets or
exceeds the quoted level of 85%.
                                                             FUEL CELL ELECTRICAL EFFICIENCY
                                                                 BI-WEEKLY ROLLING AVERAGE

                                  0.500

                                  0.475

                                  0.450

                                  0.425

                                  0.400
          Electrical Efficiency




                                  0.375

                                  0.350

                                  0.325                             FUEL CELL #1
                                                                    FUEL CELL #2
                                  0.300

                                  0.275

                                  0.250

                                  0.225

                                  0.200
                                          0   5000   10000      15000      20000      25000    30000   35000   40000
                                                                        Load Hours




                                      Figure 18: Electrical efficiency variation with load hours


                                                                           26
J.4 Cost Savings:

The total cost savings is a result of savings from electrical and thermal output of the fuel
and amounts to $2,269,788 from the inception of the project until December 31, 2006 at
the low tribal utility rates. Commercial customers paying commercial rates would save a
significantly higher amount as mentioned in Table 3 (page 6) and in the “Conclusions”
section on page 28.

K. LESSONS LEARNED
One of the lessons learned concerns the high-grade heat recovery system which serves
the boiler with make-up water. The water coming from the high-grade heat exchanger
was too hot to be utilized as make-up water. It was flashing off as steam at 280 degrees F
and had to be ratcheted down in temperature to between 208 and 212 degrees F according
to the Central Plant Manager. The inlet temperature and flow rate determine the supply
temperature. UTC Power is developing a way to set and control the temperature.

Another lesson learned relates to the low-grade heat recovery system. It is not a
recirculation type. It provides preheated domestic hot water at 140 degrees F to a
Patterson-Kelly hot water system serving the Earth Casino restrooms and kitchens. The
pumps were to cycle on and off in response to the pressure demands in the system.
However, early on it was discovered that 30 psi pressure drops were experienced prior to
the completion of the domestic water loop. Subsequently, a pressure-reducing valve
station was installed at the end of Crow Hill Road and this lessened the pressure
fluctuations to the 4-5 psi range.

Other problems emerged in the 2002 time frame with the inability of the Johnson
Controls Metasys Historian software communicating with the UTC Rockwell database
system. Data was lost as well. It was found that data external to the fuel cells required
more work than anticipated. Monitoring sensors had to be replaced more than once. Fuel
cell condensate overflowed onto the floor before a collection device was added.

L. CONCLUSIONS
The Mohegan fuel cell project successfully demonstrates that fuel cell technology can
produce clean, safe and highly reliable and efficient heat and electrical power. While at
the same time offering significant cost savings to the end used.

 The built-in heat recovery feature of the UTC Power fuel cells provided a better than
anticipated return on investment. Overall thermal savings of over $1M was achieved
since the start of the project to date (12/31/2006).

Fuel cells also have distinct advantages over conventional heat and electrical power
generation including: extremely low emissions, quiet operation, ease of installation,
ascetics (eliminate unsightly smoke stacks, etc.) which make them especially



                                             27
advantageous in populous areas where public relations, human health and the
environmental protection are of paramount consideration. The Mohegans are considering
using fuel cells for future applications.

U.S. Representative John Larson, who represents Connecticut’s First District, addressed
over 600 members of the Middlesex County Chamber of Commerce during their monthly
breakfast meeting March 14, 2006 saying “The Mohegan Tribe is leading the state in fuel
cell technology.” He also added that “fuel cell technology has great potential to create
vast power not only in Connecticut, but for the world.” He added that “we need to wean
ourselves off foreign oil dependence…The Middle East knows they hold all the cards in
the oil business. Shame on us if we don’t address this issue.”

The especially high rate of return achieved using the fuel cell waste heat recovery to
preheat boiler feed water and domestic hot water make the Mohegan fuel cell installation
a success story. Facilities with a need for reliable power generation and large amounts of
hot water such as hospitals, hotels, resorts, spas, or institutions such as college campuses,
universities or prisons would be exceptional candidates for fuel cell installations. Other
candidate considerations would be remote locations where conventional power is
unavailable. With MTGA Engineering Department’s purchase of additional
instrumentation and computers to measure fuel cell and heat recovery parameters and for
the monitoring of these systems the Tribe was able to fine tune and greatly improve the
overall operation and efficiencies of the system.

When comparing cost savings, the electrical savings ($1,247,325) was about 20% higher
compared to the thermal savings ($1,022,463). The total electric and thermal savings of
over $2.25 million at relatively low tribal utility rates shows the significance of the
potential for savings for commercial customers who are paying commercial rates. A
typical commercial customer paying Dec. 2006 commercial electric and gas rates would
have saved more than $3.5 M over the course of this period.

Approximately 850 professional scientists, engineers and visitors have asked to tour the
fuel cell installation. Since October of 2005, visitors include two university student
groups, a group of 15 from the New England Waste Management Officials Association
(NEWMOA) and a group of International Agricultural Buyers from several different
countries in Europe. In November of 2006, the EPA began their Native American Tour
with a visit to the Mohegan Demonstration Center for a tour of the fuel cells and a
discussion of other energy conservation projects. Following presentations explaining why
the Mohegan Tribe became interested in purchasing fuel cells and the global significance
of fuel cells, the visitors are introduced to PEM cell technology and given a
demonstration of those cells as they power a small appliance. Schematics show the
operational components of each of the systems. So the fuel cell installation at the
Mohegan Sun facility has been a strong success story to educate various folks such as
government officials, school and university students, industrial organizations, and the
general public about the importance of clean energy generation technologies and the
operational, environmental, and economic benefits of fuel cells in particular.




                                             28
    Appendix A

CARB 07 Test results




         29
                                    State of California
                               AIR RESOURCES BOARD
                                Executive Order DG-001-A
                          Distributed Generation Certification of
                                   UTC Fuel Cells, LLC
                         PureCell™ System Model 200 Fuel Cell

WHEREAS, the Air Resources Board (ARB) was given the authority under California
Health and Safety Code section 41514.9 to establish a statewide Distributed Generation
(DG) Certification Program to certify electrical generation technologies that are exempt
from the permit requirements of air pollution control or air quality management districts;

WHEREAS, this DG Certification does not constitute an air pollution permit or eliminate
the responsibility of the end user to comply with all federal, state, and local laws, rules
and regulations;

WHEREAS, on November 22, 2002, UTC Fuel Cells, LLC applied for a DG
Certification of its phosphoric acid PC-25 Fuel Cell and whose application was deemed
complete on December 5, 2002;

WHEREAS, UTC Fuel Cells, LLC, was issued a DG Certification on January 29, 2003,
for its PC-25 Fuel Cell;

WHEREAS, on December 21, 2005, UTC Fuel Cells, LLC applied for a modification to
its DG Certification DG-001 for the purpose of modifying the model name to Model 200;

WHEREAS, the model name change was requested in order to keep with a re-branding
effort at UTC Fuel Cells, LLC and its affiliated entity, UTC Power, LLC;

WHEREAS, UTC Fuel Cells, LLC has represented that the PureCellTM System Model
200 Fuel Cell described in their application for modification operates with the parameters
set out in the application for certification dated November 22, 2002 and can meet the
requirements set out in DG Certification DG-001;

WHEREAS, I find that the Applicant, UTC Fuel Cells, LLC, has met the requirements
specified in article 3, title 17, CCR, and has satisfactorily demonstrated that the
PureCellTM System Model 200 meets the 2007 DG Certification emission standards;

NOW THEREFORE, IT IS HEREBY ORDERED, that a DG Certification, Executive
Order DG-001-A, executed at Sacramento, California on May 24, 2006, is hereby
granted. This DG Certification:

1) is subject to all conditions and requirements of the ARB’s DG Certification Program,
article 3, title 17, CCR, including the provisions relating to inspection, denial,
suspension, and revocation;




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2) shall be void if any manufacturer’s modification results in an increase in emissions or
changes the efficiency or operating conditions of a model, such that the model no
longer meets the 2007 DG Certification emission standards; and

3) shall expire on January 29, 2007.

                                                     Catherine Witherspoon
                                                     Executive Officer
                                                     by



                                                     Robert D. Fletcher, Chief
                                                     Stationary Source Division




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             Appendix B

Selected Sections of the Service Manual




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33
34
35
36
37
38
39
    Appendix C


Letter from NEWMOA




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