Advancements in H Class Gas Turbines and Combined Cycle Power Plants

The power generation industry is facing unprecedented challenges. High fuel costs combined with an increased penetration of renewable power has resulted in greater demand for high efficiency and operational flexibility. Imperative for a reduced carbon footprint places an even higher premium on efficiency. Power producers are seeking highly efficient, reliable, and operationally flexible solutions that provide long-term profitability in a volatile environment. New generation must also be cost-effective to ensure affordability for both domestic and industrial consumers. Gas turbine combined cycle power plants provide reliable, dispatch-able generation with low cost of electricity, reduced environmental impact, and improved flexibility. GE’s air-cooled, H-class gas turbines (7/9HA) are engineered to achieve greater than 63% net, combined cycle efficiency while delivering operational flexibility through deep, emission-compliant turndown and high ramp rates. The largest of these gas turbines, the 9HA.02, exceeds 64% combined cycle efficiency (net, ISO) in a 1 × 1, single-shaft configuration. In parallel, the power plant has been configured for rapid construction and commissioning enabling timely revenue generation for power plant developers and owners. The HA platform is enabled by 1) use of a simple air-cooling system for the turbine section that does not require external heat exchange and the associated cost and complexity, and 2) use of well-known materials and coatings with substantial operating experience at high firing temperatures. Key technology improvements for the HA’s include advanced cooling and sealing, utilization of unsteady aerodynamic methodologies, axially staged combustion and next generation thermal barrier coating (TBC). Validation of the architecture and technology insertion is performed in a dedicated test facility over the full operating range. As of February 2018, a total of 18 HA power plants have achieved COD (Commercial Operation). This paper will address three topics relating to the HA platform: 1) gas turbine product technology, 2) gas turbine validation and 3) integrated power plant commissioning and operating experience.