Ansaldo Energia GT26 Heavy-Duty Gas Turbine

Overview

The Ansaldo Energia GT26 is a heavy-duty gas turbine engineered for large-scale combined-cycle and cogeneration power plants that demand top-tier efficiency, wide operational flexibility, and long-term reliability. Rated at 370 MW in single-cycle operation with a single-cycle efficiency of 41%, the GT26 has been installed in 110 units worldwide, of which 78 feature current Ansaldo Energia technology, accumulating more than 9 million estimated operating hours across utility and industrial power projects globally.

Working closely with plant engineers in the region, Seven Star LLC proudly supplies the GT26 heavy-duty gas turbine to utility power producers, EPC contractors, and independent power project developers.

Operating Principle

The GT26 is built around Ansaldo Energia’s exclusive sequential combustion technology, using a 22-stage axial compressor with 4 variable guide vanes to feed a first-stage EnVironmental (EV) annular combustor with 24 burners, followed by a 1-stage air-cooled high-pressure turbine, then a second Sequential EnVironmental (SEV) annular combustor with 24 burners, and finally a 4-stage air-cooled low-pressure turbine. By reheating combustion gases between two turbine stages rather than burning all fuel in a single combustor, the GT26 sustains high firing temperatures and efficiency across a much wider load range than a conventional single-combustion design.

This two-stage combustion architecture allows the GT26 to maintain compliant emissions performance, with NOx levels down to 15 ppm in dry gas mode, down to a minimum environmental load of approximately 15% of full plant capacity, while its solid welded rotor construction eliminates the periodic disk replacement and de-stating requirements typical of bolted-rotor competitors. In combined-cycle configuration the GT26 delivers exhaust conditions of 741 kg/s mass flow at 635°C, well suited to high-efficiency heat recovery steam generator (HRSG) integration, and the platform is currently released for operation with up to 45% hydrogen in natural gas blends without derating.

Engineering Design of the Ansaldo Energia GT26

The GT26 is a cold-end generator-driven heavy-duty gas turbine, meaning the generator connects at the compressor end of the shaft line rather than the turbine exhaust end, a configuration that simplifies exhaust ducting into the HRSG in combined-cycle plants. The turbine’s solid welded rotor is a defining mechanical feature of the platform, replacing the bolted, tie-bolt rotor construction found in many competing heavy-duty gas turbines and reducing the scope of periodic rotor inspection and refurbishment work over the machine’s service life.

Operators can switch the GT26 online between two operating modes, a Performance Optimized mode for maximum power output and a Maintenance Cost Optimized mode that extends time between scheduled inspections by up to 30%, giving plant operators direct commercial control over the balance between output and maintenance spend. Scheduled hot gas path inspections are set at intervals of 32,000 hours, and in combined-cycle configuration the GT26 achieves a net efficiency exceeding 61%, with plant output reaching 540 MW in a single-unit (1+1) block or up to 1,083 MW in a 2+1 multi-shaft configuration.

Key Features

The Ansaldo Energia GT26 combines sequential combustion technology with a welded rotor design to deliver strong performance across a wide operating range. Core capabilities include:

• The Ansaldo Energia GT26 delivers single-cycle power output of 370 MW at 41% efficiency, rising to over 61% net efficiency in combined-cycle operation.
• Combined-cycle plant output up to 540 MW (1+1 configuration) or 1,083 MW (2+1 configuration).
• Exclusive sequential combustion technology using an EV combustor and an SEV combustor, each with 24 burners.
• Solid welded rotor construction eliminating tie-bolt disk replacement and reducing long-term maintenance scope.
• Superior turndown capability with a minimum environmental load of approximately 15% of plant capacity.
• Hydrogen co-firing capability of up to 45% by volume in natural gas blends without power derating.
• Switchable Performance Optimized and Maintenance Cost Optimized operating modes, extending service intervals by up to 30%.
• Proven fleet history of 110 units installed worldwide and more than 9 million estimated operating hours.

Industrial Applications

The Ansaldo Energia GT26 is deployed primarily in large utility-scale combined-cycle power plants where its high efficiency and wide operational flexibility deliver strong lifecycle economics for grid-connected generation. Its superior turndown capability, holding all components fully online down to roughly 15% plant load, makes it particularly well suited to power systems in the GCC that must accommodate variable demand profiles and growing renewable penetration, allowing the plant to remain dispatch-ready without the emissions penalty of a full shutdown and restart cycle.

With fast quotation turnaround and technical support, Seven Star LLC distributes the GT26 to utility developers, independent power producers, and industrial cogeneration operators pursuing large combined-cycle projects across the Sohar and Salalah economic zones and other planned power expansion sites in Oman. The turbine’s hydrogen co-firing capability also positions it as a practical option for national utilities and industrial power producers preparing for phased decarbonization of baseload generation capacity across the region.

Technical Specifications

The Ansaldo Energia GT26 specification sheet below lists full technical parameters for the Ansaldo Energia GT26 heavy-duty gas turbine:

Request a Quote for Ansaldo Energia GT26

nThe Ansaldo Energia GT26 remains one of the most specified heavy-duty gas turbines for large combined-cycle projects in the region.
To submit a formal Request for Quote (RFQ), confirm regional delivery timelines, or obtain the complete technical datasheet for the Ansaldo Energia GT26 heavy-duty gas turbine, contact the power generation equipment division at Seven Star LLC regarding the Ansaldo Energia GT26. With engineering support in Muscat, our engineers support utility, EPC, and industrial customers with commercial sourcing, technical clarification, and long-term project support for large-scale combined-cycle power installations.

Browse the full Ansaldo Energia range or see more Gas Turbines products supplied by Seven Star LLC in Oman and the GCC.