The Topolobampo III combined-cycle power plant is a 766MW greenfield gas-fired power plant being developed in the state of Sinaloa, Mexico. Iberdrola is the project developer and is also responsible for the plant operation and maintenance.

Estimated to cost $400m, the project is expected to generate electricity sufficient to supply for more than 2.5 million Mexican homes.

Construction of the power plant is expected to be started in 2019, with commissioning scheduled to be completed by June 2020.

Topolobampo III combined-cycle power plant make-up

The Topolobampo III combined-cycle power plant will comprise two 7HA.01 gas turbines, a D650 steam turbine, three generators, and two heat recovery steam generators (HRSGs). It will be the first power plant in Mexico to use 7HA.01 gas turbine.

The 7HA.01 air-cooled gas turbine requires just ten minutes for ramp-up to full load. It is capable of producing up to 50MW a minute in 1X1 configuration and 100MW a minute in 2X1 configuration.

The turbine operates at a combined-cycle efficiency of more than 63% and features a simplified dual-fuel system that consumes less water and avoids recirculation. The compressor of the turbine will have 14 stages along with 3D aerodynamic foils, three stages of variable stator vanes, and field-replaceable blades.

The need for on-site gas compression is eliminated due to the advanced technology of the compressor.

GE’s D650 steam turbine comes with a single bearing design, which offers increased power density and reliability. The three-casing double-flow low-pressure (LP) section of the turbine uses a self-synchronizing clutch to minimize the steam demand during start-ups. It is capable of achieving 85% load in less than 20 minutes under hot start conditions.

The maximum main inlet pressure and temperature of the steam turbine are estimated to be up to 2,680psi (185 bar) and up to 1,112°F (600°C) respectively.

The control system is equipped with GE’s digital power plant capabilities, which feature advanced controls and control systems running on the advanced Predix technology platform. The platform enables the usage of real-time data to ensure stable and efficient operations.

Transmission and off-take of power

Two transmission lines and two substations will be constructed in the states of Sinaloa and Sonora, under a €21m ($24.5m) contract, for transmitting the power generated by the Topolobampo III combined-cycle power plant.

The transmission lines and substations will be connected to the Mexican national grid.

The power output of the plant will be purchased by the Federal Electricity Commission (CFE) of Mexico, under a 25-year power purchase agreement, at fixed capacity rates.

Contractors involved

ACCIONA was awarded the contract for the design, construction, equipment installation, operation, and maintenance of the Topolobampo III combined-cycle power plant. It is also responsible for the construction of the transmission line from the power plant to national grid.

General Electric (GE) is the supplier of gas turbines, steam turbine, generators, and HRSGs for the project.