Turbine technology |Upgrade
Ansaldo Energia upgrade packages boost AE/V94.3A and SGT5-4000F fuel and operational flexibility
The growing share of renewable energy and evolving environmental regulations are driving the need for gas-fired power plants to be more flexible. Ansaldo Energia has developed upgrade packages for the AE/V94.3A and SGT5-4000F gas turbine fleet, enabling faster ramp rates, reduced minimum environmental load (MEL) and enhanced fuel flexibility, including hydrogen blends up to 40%, as well as HVO and diesel oil. Combined with the AutoTune digital optimisation system, these solutions improve performance, reduce emissions, and extend component lifetimes. The upgrades are retrofittable with minimal downtime, providing a cost-effective pathway to support the energy transition and participation in ancillary services markets
Marcello Benvenuto GT Product and Portfolio Specialist and Roberto Bittarello Digital and Shaft Line Product Manager, Ansaldo Energia
In a fast-paced market, requirements for flexibility, both operational and fuel, are becoming the cornerstone drivers for heavy- duty gas turbine (GT) design and upgrades. In fact, with the increasing portion of electricity produced from renewable energy sources, and the latest environmental requirements (especially in the EU), conventional power plants need to become more and more flexible, reliable, and resilient.
Specific upgrade packages developed by Ansaldo Energia, described below, pave the way for continuing utilisation of gas-turbine-based power plants during the energy transition, providing economic benefits to their owners/ operators and presenting opportunities to participate in ancillary services markets. The packages, especially intended for the existing service fleet of AE/V94.3A and SGT5- 4000F gas turbines, meet the demand for flexibility in terms of faster start up time, grid frequency control, extended operational range (from minimum environmental load (MEL) to
Figure 2. Features contributing to MEL reduction. Source of image: Ansaldo Energia
base load), and fuel flexibility. All while keeping pollutant emissions below local regulation limits. Figure 1 gives an indication of the improved operational flexibility achieved. Ansaldo Energia’s AE94.3A is a proven F-class heavy duty gas turbine featuring a 15-stage axial compressor, an annular combustor
with 24 dry low NOx burners and a 4-stage turbine with cooling
Load rate Load rate
Load rate
MEL* reduction Purge credit Time Baseline Flexibility
Figure 1. Improved operational flexibility (*MEL= minimum environmental load). Source of image: Ansaldo Energia
air brought in by a mix of secondary air system lines, external and internal-rotating (the latter employing airflow holes in two of the compressor discs).
The AE94.3A, accounting for more than 125 units sold worldwide, has accumulated more than 5 million equivalent operating hours worldwide in many different operating conditions.
AutoTune
AutoTune is an online optimisation system that automatically adjusts gas turbine operating parameters. It reduces combustion instability problems in every operational phase of the gas turbine, thus increasing GT flexibility with the consequent possibility of improving performance in areas such as ramp rate, minimum load and maximum power output.
AutoTune continuously analyses combustion parameters as well ambient conditions, operational parameters, fuel gas composition and emission level at exhaust, and actively adjusts the GT controller through specific regulation logics for pilot gas flow rate variation, TETC (turbine exhaust temperature control) setpoint variation and load reduction. It outperforms previous adaptive tuning strategies based on
36 | July/August 2025|
www.modernpowersystems.com
Power (MW)
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