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 is a multi-shaft gas turbine featuring a free-spinning power turbine, making it well-suited for dynamic and high-demand environments such as those found in oil and gas operations. In this design, the high-pressure turbine and compressor are mechanically independent from the low-pressure power turbine. This separation allows the power turbine, which drives the electric generator or mechanical load, to respond rapidly to changes in load demand. Its ability to accelerate quickly makes it ideal for applications where maintaining grid stability or mechanical output is critical. In scenarios where frequency fluctuations occur, the free power turbine can quickly compensate, helping to stabilize the grid and ensure smoother operation of all connected systems.

In its standard configuration, the LM2500 is equipped with a six-stage, low-speed power turbine. This turbine operates at a nominal speed of 3600 rpm and is designed to deliver reliable shaft power in steady-state conditions, making it particularly effective for electric power generation or mechanical drive in pipeline and process operations.

For applications requiring greater flexibility or higher continuous output speeds, the LM2500+G4 variant offers enhanced capabilities. It is available with either the standard six-stage, low-speed power turbine or an alternative two-stage high-speed power turbine. The high-speed variant is engineered for mechanical drive and other demanding industrial uses, with a design speed of 6100 rpm and an operating range from 3050 to 6400 rpm. This configuration supports continuous high-speed shaft output where needed and is particularly beneficial for compressors and other rotating equipment in oil and gas facilities.

Both the six-stage and two-stage power turbines can be operated over a cubic load curve, providing the adaptability required for variable load profiles commonly encountered in oil and gas operations. This flexibility, combined with the LM2500’s rapid response characteristics and modular design, makes it a dependable choice for critical infrastructure in upstream, midstream, and downstream sectors.

The LM2500+ DLE gas turbine is a high-performance solution for power generation in industrial, onshore, and offshore environments where emissions control and water availability are key concerns. Delivering over 30 megawatts of power and up to 40% thermal efficiency in simple cycle operation, it offers reliable performance with low environmental impact.

At the core of its design is the advanced Dry Low Emissions (DLE) combustion system, which reduces NOx and unburned hydrocarbon emissions without the need for water or steam injection. The system achieves this by precisely managing combustion conditions and lowering flame temperature. A triple annular combustor configuration enables fuel to burn more evenly at lower temperatures across a larger area, while new electrically actuated fuel metering valves enhance control and reduce complexity compared to older electro-hydraulic systems.

The LM2500+ DLE also features a 17-stage axial compressor for increased airflow and output, along with a modular, open design that enables faster maintenance and engine replacement. Its fast start capability makes it suitable for operations requiring multiple starts and stops per day.

Whether powering industrial facilities, pipeline networks, or combined heat and power (CHP) systems, the LM2500+ DLE offers a dependable and efficient gas turbine solution that balances operational flexibility with emissions performance.