M701G Series

Gas Turbines
  • Standalone Gas Turbine Output

    330 MW class

  • Combined Cycle Output

    500 MW class / 1,000 MW class

  • Combined Cycle Efficiency

    More than 59%

High-performance large-capacity gas turbines for 50Hz power generation

In February 1997, the first unit of the 1,500°C Class M501G Series gas turbines came into commercial operation. This series features the use of steam for cooling combustors. Developed as a model with a similar design, the M701G Series for 50 Hz power generation began commercial operation at the middle of 1999.

Overall Design

The gas turbine unit is based on the basic structure adopted in the early 1970s that has accumulated a track record of at least 40 years. Its main features are as follows:

  • A compressor shaft end drive reduces the effect of thermal expansion on alignment
  • A rotor with simple single-shaft two-bearing support
  • A rotor structure has bolt-connected discs with the torque pins in the compressor section and CURVIC couplings in the turbine section to ensure stable torque transmission
  • An axial flow exhaust structure advantageous in combined cycle plant layouts
  • Horizontally split casings that facilitate field removal of the blades with the rotor in place


Axial flow compressors designed with advanced airfoil design technologies are introduced. They feature large capacity, high efficiency and a high pressure ratio. Variable inlet guide vanes ensure operational stability at the start-up and enhanced performance at partial load in combined cycle operation.

The inlet guide vanes and variable stationary vanes at the first three stages are controlled to ensure stable operation at the start-up and enhanced performance at partial load in combined cycle operation.


A premixing low NOx combustor is a steam-cooled type, composed of one pilot burner and eight main burners that surround it. The combustor has an air bypass mechanism that enables fuel-air ratio regulation in the combustion region.


Four-stage axial flow turbines in a three-dimensional aerodynamic design are adopted. The vanes at the first three stages are air-cooled. Among these, those at the first two stages adopt directionally solidified (DS) materials with thermal barrier coating (TBC). Despite the rise in temperature, application of advanced cooling technologies and the TBC helps to maintain the metal temperature of turbine blades at the level of conventional gas turbines.



Compressor Number of Stages 14
Combustor Number of Cans 20
Cooling Method Steam Cooled
Turbine Number of Stages 4
Rotor Number of Rotors 1
Output Shaft Cold End
Rated Speed 3,000 rpm
Gas Turbine Approx. L × W × H 14.4 × 6.2 × 6.7 m
Approx. Weight 490 ton

Simple Cycle Performance

Frequency 50 Hz
ISO Base Rating 334 MW
Efficiency 39.5 %LHV
LHV Heat Rate 9,110 kJ/kWh
8,630 Btu/kWh
Exhaust Flow 755 kg/s
1,664 lb/s
Exhaust Temperature 587 °C
1,089 °F
Exhaust Emission NOx 25 ppm@15%O2
CO 10 ppm@15%O2
Turn Down Load 60 %
Ramp Rate 22 MW/min
Starting Time 30 minutes

Combined Cycle Performance

1 on 1 Plant Output 498.0 MW
Plant Efficiency 59.3 %
2 on 1 Plant Output 999.4 MW
Plant Efficiency 59.5 %
Starting Time

Performance Correction Curves

  • Effects of Compressor Inlet Temperature on Gas Turbine Performance (Typical)

  • Effects of Barometric Pressure on Gas Turbine Performance (Typical)


Typical Plant Layout - 1 on 1 configuration, single-shaft

  • Gas Turbines
  • Steam Turbines
  • Generators
  • Inlet Air Filter
  • Heat Recovery Steam Generator (HRSG)
  • Electrical / Control Package
  • Main Transformer
  • Condenser

Typical Plant Layout - 2 on 1 configuration

  • Gas Turbines
  • GT Generator
  • Steam Turbines
  • ST Generator
  • Inlet Air Filter
  • Heat Recovery Steam Generator (HRSG)
  • Electrical / Control Package
  • GT Main Transformer
  • ST Main Transformer
  • Condenser

Main Delivery Records


Higashi-Niigata Thermal Power Station Unit 4, Tohoku Electric Power Co., Inc. (Japan)
1,700 MW, 4 x M701G


Chiba Thermal Power Station Unit 3, TEPCO Fuel & Power, Inc. (Japan)
1,500 MW, 3 x M701GAC