The GE Gas Turbine Lineup: Heavy-Duty Frames, Aeroderivatives and Where Each Fits

How GE Names Its Turbines

The naming follows a pattern that makes the lineup easier to read once you know it. For the heavy-duty frames, the first digit indicates the family and, for many models, the grid frequency: 7-series machines are designed for 60 Hz grids and 9-series for 50 Hz. The 6-series machines are smaller and use a load gearbox so they can serve either frequency. The letter that follows, such as B, E, F or HA, marks the technology class, with later letters bringing higher firing temperatures and output.

Aeroderivatives carry an LM prefix, for land and marine, followed by a number that traces back to the aircraft engine they came from. The TM prefix marks a trailer-mounted version.

The Heavy-Duty Frame Families

Heavy-duty turbines are built as industrial machines from the start. They are heavy, rugged and designed for long periods at steady load with inspections carried out in place.

For many projects in emerging markets, the 6B and E-class machines remain attractive because of their fuel tolerance and the depth of service experience behind them. Our page on remanufactured Frame 6B units for power stations looks at that option in detail.

The Aeroderivative Families

GE’s aeroderivatives come from its aircraft engine business. The gas generator section of each is closely related to an engine that has flown many millions of hours, adapted for ground use with a power turbine, industrial controls and fuel systems for natural gas or distillate.

• LM2500: derived from the CF6 aircraft engine family, the most widely used aeroderivative in GE’s range, found in power plants, pipelines and naval ships.
• LM6000: a larger two-shaft design based on the CF6-80C2, popular for peaking and flexible power plants because of its fast start and high simple-cycle efficiency.
• LMS100: an intercooled design that combines frame and aeroderivative technology for high efficiency in a flexible unit.
• TM2500: a trailer-mounted package built around the LM2500, designed for rapid deployment and relocation.

USP&E’s guide to the LM2500 and LM6000 compares the two most common aeroderivatives in detail, and our own pages on the GE TM2500 cover the mobile version.

Frame or Aeroderivative: Matching the Duty

The choice between branches is mostly a question of how the plant will run.

1. Steady output for most of the year, on varied or lower-grade fuel: a heavy-duty frame is usually the better fit.
2. Many starts and stops, rapid ramping or peaking: an aeroderivative handles cycling with less maintenance penalty.
3. Hot or high sites where weight and footprint matter: aeroderivatives are compact, though both lose output in heat.
4. Need to move the unit or install it quickly: a trailer-mounted aeroderivative is designed for that.
5. Remote site with limited specialist support: consider how overhauls will be carried out, since aeroderivative modules can be exchanged while frames are inspected in place.

Our article on surplus frame and aeroderivative turbines adds the questions to ask when the unit is not new.

Fuel, Emissions and Site Conditions

Both branches burn natural gas as their main fuel, and most can run on distillate as a backup. Heavy-duty frames tolerate a wider range of gas compositions and some can burn heavier liquid fuels with treatment. Aeroderivatives are more particular about fuel quality and usually need clean, dry gas at relatively high pressure, which may mean a fuel gas compressor on site.

Emissions control depends on the combustor. Dry low-emission systems reduce nitrogen oxides without water; older or liquid-fuel configurations may need water or steam injection. Site conditions matter for every model: output falls as ambient temperature and altitude rise, and inlet filtration must suit dust, salt or humidity at the site.

Lead Times, Stock and Remanufactured Units

Demand for gas turbines has risen sharply in recent years, and factory slots for new heavy-duty machines can be booked far ahead. That has made stock, surplus and remanufactured units a serious option for projects with tight schedules. A well-documented unit with a known maintenance history can be delivered and installed much sooner than a new build.

Check the unit’s hours, starts, inspection records and the condition of its hot section, and confirm the controls can be supported. USP&E’s gas turbine inventory lists units with that information, and our new gas turbine buying guide covers new orders.

Controls, Upgrades and Long-Term Support

A turbine’s controls age faster than its steel. Older GE units may run on earlier generations of the Mark control family, and parts or software support for the oldest versions can be limited. When buying a used or remanufactured unit, check which control system is fitted and whether an upgrade is planned or priced.

Hardware upgrades are also common across the lineup. Hot gas path improvements, combustion upgrades for lower emissions and digital monitoring packages can extend inspection intervals or raise output. A buyer should know which upgrades a unit already has, since they affect performance, maintenance planning and spare parts.

Long-term support can come from the original maker, from independent service providers or from a mix of both. For remote sites, the availability of field engineers and the speed of parts supply often matter more than the badge on the service agreement.

Questions to Ask About Any GE Unit on Offer

Whether new, stock or remanufactured, a short set of questions brings out what matters before price is discussed.

1. What is the exact model and configuration, including combustor type and fuel capability?
2. How many fired hours and starts has it run, and when was the last hot gas path or major inspection?
3. Which control system and software version is installed, and is it supported?
4. Which upgrades have been fitted since the unit left the factory?
5. Where is it stored, how has it been preserved, and are preservation records available?
6. What documents come with it: inspection reports, test records, drawings and parts lists?

Clear answers to these questions make it much easier to compare a stock unit against a new order, or one family against another.

From Turbine to Power Plant

Whichever model is chosen, the turbine is only part of the plant. Fuel supply and treatment, electrical systems, controls, civil works and permits all need to come together. USP&E’s overview of natural gas turbine power plants explains how those parts fit, and the same team can carry the project from equipment selection through construction to operation.