High-Efficiency Gas Turbine
Combined Cycle Plant for PGE
in the U.S. Starts CommercialOperation
POWER SYSTEMS HEADQUARTERS
POWER SYSTEMS INTERNATIONAL OPERATIONS DEPARTMENT

The Port Westward Combined Cycle Plant of Portland
General Electric (hereinafter referred to as PGE) in the
United States started commercial operation on June 11,2007. This plant, one of the highest-efficiency gas turbine
combined cycle plants on the U.S. West Coast, is now mainly
performing rated operation.

This is a multi-shaft, reheat type combined-cycle plant.
MHI's scope was to supply the main equipment, including
the GT, ST, HRSG (Heat Recovery Stream Generator), andgenerators, together with technical advisors (TA) for installation and commissioning. BV, meanwhile, took part ininstallation and commissioning in the field. MPSA
(Mitsubishi Power Systems Americas Inc.), an MHI subsidiary in the U.S., handles communications with the customer(PGE) and EPC contractor (BV).

1. Outline of the plant

2. Special notes on the main equipment

The plant is located in Oregon, a state well known for its
bountiful wilderness. It stands along the banks of the Columbia River in the northern part of Clatskanie, about 100
km north-northwest of Portland, the state capital. The site
is within a reserve, on lands once peopled by the indigenous
native population. Mitsubishi Heavy Industries, Ltd. (MHI)
received the order for the plant in September 2004, during
the tail end of the GT (gas turbine) boom in the U.S. Starting from 1999, MHI had delivered six F-type GT units andeleven G-type GT units to U.S. utilities and owners before
this order from PGE.
MHI delivered the GT/ST (steam turbine), the generator,
and the rest of the main equipment into the field in January
2006, after completing the design, manufacture, and transportation. The delivery took place about half a month earlier
than the contracted date. Next, MHI dispatched technicaladvisers (TA) to the field for the construction and a trial run,at the request of Black & Veatch Corporation (BV), the EPC(Engineering, Procurement and Construction) contractor.
PGE started commercial operation upon completion of theconstruction and commissioning by BV. The specificationsof the main plant equipment are shown in Table 11.

(1) M501G1 type gas turbine
For the gas turbine, MHI adopted the M501G1, a
modified version of the M501G, a GT with a track recordof 11 deliveries in the U.S. The M501G1 is state of theart, with enhancements in both efficiency and reliability
compared to the original model, and a GT combustion
temperature of 1,500oC. An actual loading test was completed in the verification power generation facility within
Takasago Machinery Works in 2003. Principal improvements from the M501G type include an improved exhaust
diffuser, and a turbine blade with enhanced aerodynamic
characteristics and cooling efficiency. Compared withthe M501G, the M501G1 produces about 3% more output with an approximately 1% improvement in efficiency.
(2) TCA (turbine cooling air) cooler for gas turbines
This is a vertical type cooler designed to use boiler
feed water as cooling water. MHI has adopted its mostadvanced type, incorporating numerous special element
technologies developed in-house (multiple-stage tubes,thermal sleeve structural nozzle, etc.).
(3) FGH (fuel gas heater) for gas turbines
MHI has adopted a shell-and-tube type FGH (fuelgas heater) with high compactness, maintainability,and reliability.

Table 1 Plant and specifications for the main equipment
Outline of plant
Guaranteed
outputGuaranteed
efficiency
Guaranteed
emission

1-on-1 gas turbine combined cycle plant
398 000kW (Without duct firing),
423 700kW (During duct firing)
52.1% (Without duct firing)
51.0% (During duct firing)NOx-2.5ppm CO-4.9ppm
VOC-7.74Ib/H NH3 -8ppm

3. Summary
As the first M501G1 type GT combined cycle in the UnitedStates, service at loads close to the rated load has been continued since the start of commercial operation. MHI has also
obtained favorable comments from the customer on theperformance and reliability of every piece of MHI-made equipment, including the GT and ST. An LTSA (Long-Term ServiceAgreement) contract has already been concluded. We would
like to continue to support long-term commercial operation
by working closely and cooperatively with MPSA in responseto electric power demands in the U.S. northwest while also
trying to conserve the bountiful wilderness of Oregon state.

Specifications for main equipment
Gas turbine
M501G1 GT, indoor type, premixed type,gas firing; 1unit
Steam turbine
TC2F-29.5"; 1unit
HRSG
Triple-pressure natural-circulation
reheat boiler; with duct firing
Generator
For GT: Hydrogen gas cooling,and others
For ST: Air cooling, Static excitation system

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 44 No. 4 (Dec. 2007)

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