Beyond efficiency: Operational flexibility powers future of power generation

More than high efficiency, modern power systems require gas turbines that respond quickly to changing grid conditions.

As gas-fired power plants are now called upon to respond to fluctuating renewable energy generation, operational flexibility has elevated to the same level of importance as efficiency. For power producers, the ability to start quickly, operate at low loads, and respond rapidly to changing grid conditions has become essential to maintaining reliability whilst capturing commercial opportunities in dynamic electricity markets.

As pointed out by Federico Bonzani, Chief Technology Officer at Ansaldo Energia, in an interview with Asian Power, the changing nature of power systems is redefining what operators expect from modern gas turbines.

“Efficiency is still very important, but is no longer enough on its own,” he said. “A modern power plant must be able to start quickly, ramp up and down, operate at low load, and support the grid demand. In that sense, flexibility is not just an additional feature of power generation; we may call it one of the key enablers of a reliable energy transition.”

Renewable-powered grid

Ansaldo Energia developed its GT36 H-Class gas turbine with these evolving operating requirements in mind. GT36 is engineered to maintain strong performance well beyond full-load operation, delivering more than 62% combined-cycle efficiency and over 800 MW of output in combined-cycle configuration.

This technology does not focus solely on peak efficiency. It supports grids where renewable output changes throughout the day to allow operators to respond to demand fluctuations.

“GT36 is not a machine designed to run only efficiently at full load,” Bonzani explained. “It has been designed to follow the needs of the grid.”

One of GT36's defining technologies is its sequential combustion system, a feature unique to Ansaldo Energia. By staging combustion across two combustion chambers, the system enables the turbine to maintain stable operation and emissions compliance.

The technology allows the turbine to adapt to different natural gas compositions as well, including varying LNG blends commonly used in Asia. Furthermore, it supports hydrogen blending of up to 70% by volume and provides additional flexibility for future decarbonisation pathways.

Operational flexibility has already become an economic advantage. Electricity markets increasingly reward assets that can respond rapidly to changing system conditions. Faster start-up and ramp-up capabilities allow operators to dispatch power precisely when needed, particularly during periods when renewable generation declines unexpectedly.

GT36 delivers ramp rates of up to 100 MW per minute, which makes the plant capable of reaching full load in less than 15 minutes under proven operating conditions.

“The fast start and high ramping capability of GT36 are not only an engineering achievement, but they also directly improve the way the plant can be dispatched and then monetised in today's electricity markets,” Bonzani said. 

Equally important is the turbine's ability to remain online at very low output levels. As renewable generation rises during daylight hours, gas turbines operate in standby mode, ready to increase output as solar production declines later in the day.

GT36 addresses this challenge with its high part-load efficiency and an exceptionally low minimum environmental load of around 15%. This avoids unnecessary shutdowns and restarts, allowing operators to reduce fuel consumption and minimise mechanical wear, whilst maintaining operational readiness and maximising value in increasingly dynamic electricity markets.

Asia's evolving power systems

Bonzani believes technologies such as GT36 will become increasingly important as countries seek to integrate larger shares of renewable energy without compromising system reliability.

“The challenge is not only to add more and more renewables. We are talking about renewable integration into the existing system,” he said. “Flexible gas turbines can provide power when it is needed, support the grid during fast changes and enable a high share of renewables.”

Ansaldo Energia complements GT36 and the rest of its gas turbine portfolio with digital solutions such as Integrated Plant Support (IPS) that uses advanced monitoring and diagnostics and enables predictive maintenance. In addition to this, the company offers Plant Integrator, a platform that automatically optimises hybrid plant performance through software and hardware integration.

GT36's operating fleet also demonstrates flexibility and reliability, with five units currently in operation. Collectively, these units have recently surpassed 80,000 Equivalent Operating Hours (EOH), marking a significant milestone for Ansaldo Energia's flagship H-class technology and highlighting its maturity and proven operational performance. Additional units have already been reserved for projects in Europe, and discussions continue across Europe, the Middle East, and Asia.

The dynamic transformation of electricity systems is pushing the industry's priorities to evolve. High efficiency remains essential, but it is no longer sufficient on its own. 

“Combining utility-scale output, world-class efficiency and operational flexibility, GT36 is designed to support power systems as they integrate growing shares of renewable energy whilst maintaining reliability, security of supply and grid stability.”

To know more about Ansaldo Energia and its GT36 H-class gas turbine, visit https://www.ansaldoenergia.com/.