The LM2500+G4 is an advanced variant of the LM2500+ aeroderivative gas turbine, designed to provide increased output and thermal efficiency through a set of targeted design upgrades. It retains the core architecture of the LM2500+ but introduces changes to the flow path that increase overall engine performance.

The primary difference between the LM2500+G4 and the LM2500+ is the increased flow capacity in the high-pressure (HP) compressor, HP turbine, and low-pressure turbine. These modifications raise the overall pressure ratio from 23.6 to 24.2, resulting in higher thermal efficiency and greater mass flow. The design changes are relatively limited, focusing mainly on minor geometry adjustments to blades and vanes to accommodate the increased flow.

In the high-pressure turbine, the G4 version includes improved blade cooling and upgraded materials. These changes enable the turbine to handle higher temperatures, contributing to both improved performance and component durability. To maintain proper rotor thrust balance with the updated flow path, the effective area of the compressor discharge pressure seal was also adjusted.

In terms of operational performance, the LM2500+G4 offers measurable improvements over the LM2500+ across a variety of ambient conditions. For example, it delivers approximately 11% more power in cold conditions and 12% more in hot conditions (running data to -50 deg F and start data to –40 deg F). In combined-cycle mode, the G4 variant is expected to provide a power increase of 8.5% and a heat rate improvement of 0.75% compared to the LM2500+.

The LM2500+G4 supports two power turbine configurations:

• A six-stage, low-speed power turbine, typically used for power generation applications with a nominal speed of 3600 rpm.
• A two-stage High-Speed Power Turbine (HSPT), used for mechanical drive applications, designed for a nominal speed of 6100 rpm, with an operating range from 3050 to 6400 rpm.

Both configurations support operation over a cubic load curve, which allows the turbine to match power output with varying mechanical loads — a feature especially useful in pipeline compression and similar variable-load industrial applications.

The Single Annular Combustor (SAC) version of the LM2500+G4 is designed for oil and gas applications that prioritize consistent performance, fuel flexibility, and emissions control—such as LNG facilities, gas processing plants, and pipeline compression, both onshore and offshore.

What makes the SAC version different is its simpler combustor design compared to dual annular or premix types. The SAC uses a through-flow, venturi swirler to ensure an even temperature profile at the turbine inlet, helping extend hot section life. It features individually replaceable fuel nozzles, a durable machined-ring liner, and a thermal barrier coating for better resistance to high temperatures and corrosion. This design supports both dry operation (with higher emissions) and water or steam injection to reduce NOx when needed—making it adaptable to site-specific emission regulations.

The LM2500+G4 SAC builds on the proven LM2500+ design, with approximately 10% more power. This gain comes from increased airflow, improved internal cooling, and material upgrades—while keeping the same number of compressor and turbine stages. The 17-stage high-pressure axial compressor and the basic engine layout remain unchanged, making it easy to maintain and service.

The engine can run on a wide range of liquid and gas fuels, allowing flexibility in remote or supply-constrained locations. It achieves up to 40% thermal efficiency in simple cycle mode. Water-injected operation enables NOx emissions as low as 25 ppm (gas) and 42 ppm (liquid).

In short, the LM2500+G4 SAC is well-suited for high-power mechanical drive and power generation in harsh or remote oil and gas environments, offering a balance of power output, fuel versatility, and emissions control.

The LM2500 Gas Generator is the core component of the LM2500 gas turbine, responsible for producing the high-energy gas flow needed to drive the power turbine. It features a 16-stage axial compressor that efficiently compresses incoming air, a single annular combustor where fuel and air mix for optimal combustion, and a two-stage high-pressure turbine that extracts energy to power the compressor.

Designed for durability and high performance, the LM2500 Gas Generator supports a wide range of fuel types, including natural gas and liquid fuels, enabling flexible operation in various industrial and marine settings. Its modular construction allows for easier maintenance and faster engine removal or replacement, minimizing downtime.

With advanced aerodynamics and robust engineering, the LM2500 Gas Generator delivers reliable, efficient gas flow, helping ensure consistent power output and lower emissions across demanding operating conditions.

The LM2500+ DLE in a 1x1 combined cycle configuration—one gas turbine, one heat recovery steam generator (HRSG), and one steam turbine—delivers significantly higher efficiency, exceeding 50% in combined cycle mode.

Designed for high thermal efficiency, fast start capability, and reduced emissions, the LM2500 family is widely used across onshore and offshore environments, including industrial plants, pipeline stations, CHP systems, and utility-scale power production.

The DLE combustion system enables the LM2500+ to maintain low NOx and CO emissions without the need for water or steam injection—simplifying operations and reducing water-related maintenance.

Key features include:

• Triple annular combustor design for even temperature distribution and lower emissions across the power range
• Electrically actuated DLE fuel valves replacing traditional electro-hydraulic SAC valves for better control
• 75 pre-mixers in 30 external modules, creating a consistent lean fuel/air mixture
• NOx emissions ≤15–25 ppm and CO emissions ≤25 ppm (on natural gas, full load)

With fast ramp-up—achieving base load from cold start in under five minutes—the LM2500 is an ideal choice for fast-start and cycling applications. This performance makes it well suited to dynamic grid environments and industrial use cases requiring quick responsiveness.