Aeroderivative vs Heavy-Duty Gas Turbines: 2026 Comparison

By Green Gas Turbines Team · Published December 16, 2025 · 18 min read

Which Type Should You Choose?

Choose an aeroderivative first when the project needs smaller modular blocks, very fast starts from an offline state, frequent start-stop duty, a compact or mobile package, offshore power or mechanical drive, black-start capability, or an engine-exchange maintenance strategy.

Choose a heavy-duty frame turbine first when the project needs hundreds of megawatts per unit, maximum combined-cycle efficiency, a large steam host, high annual energy production, or the lowest plant complexity per installed megawatt.

Then test the apparent winner against the actual dispatch profile. A modern heavy-duty simple-cycle unit can be a credible peaker, while an aeroderivative combined-cycle plant can take roughly as long to reach full plant load as a rapid-response H-class combined cycle. The old rule—“aero for peaking, frame for baseload”—is now only a starting hypothesis.

Aeroderivative and Heavy-Duty Do Not Mean Simple and Combined Cycle

Aeroderivative gas turbines adapt aviation-engine architecture for stationary service. Their high power density, multiple-spool designs, modular cores, and relatively low thermal mass support compact packaging and rapid transient operation. Current examples include the GE LM2500 and LM6000, Siemens Energy SGT-A05 and SGT-A35, and Mitsubishi Power FT8 and FT4000 families.

Heavy-duty or frame gas turbines are designed specifically for stationary power and industrial duty. Current large-frame examples include GE Vernova's 7HA and 9HA, Siemens Energy's SGT-8000H and SGT-9000HL, and Mitsubishi Power's J-series.

Both types can be installed in simple cycle, combined cycle, or CHP configurations. Both can operate at baseload or cycle. There is also a middle group of industrial gas turbines that blends features of the two categories, so procurement should never rely on category names alone.

Current Published Performance: Selected Examples

These figures show how wide each category has become. They are not bids and should not be treated as one-to-one rankings.

All figures are manufacturer-published and generally based on natural gas and stated reference conditions. Net/gross basis, ISO corrections, frequency, auxiliaries, emissions equipment, and balance-of-plant scope vary. Request a common performance basis before comparing bids.

Start Time: Define the Finish Line Before Comparing Minutes

A quoted start time is meaningless unless the start condition and finish line are defined. At least four clocks are used in gas-turbine marketing and contracts:

1. Command to breaker closure: when the generator first synchronizes and exports power.
2. Command to emissions-compliant minimum load: when the plant can remain online within permit limits.
3. Command to full gas-turbine load: the usual basis for a simple-cycle fast-start claim.
4. Command to full combined-cycle plant load: including HRSG and steam-turbine thermal constraints.

The thermal state also matters. A hot restart after a short shutdown is not a warm or cold start after days offline. Purge requirements, fuel system configuration, HRSG design, steam-turbine stress limits, emissions-compliance loading, and auxiliary availability can all change the result.

The current GE factsheets demonstrate the comparison problem clearly. The LM6000 PF+ SPRINT is listed at 5 minutes in simple cycle and 30 minutes for a 1x1 combined-cycle rapid-response hot start. The much larger 7HA.03 is listed at 10 minutes to full gas-turbine load and less than 30 minutes for the combined-cycle plant. If the market product requires full combined-cycle output, “5 minutes versus 30 minutes” is the wrong comparison.

Ramp Rate: MW/min Is Only Half the Metric

Ramp rate should be reported as both MW/min and percent of rated output per minute. Absolute MW/min describes how much capacity reaches the grid; the normalized figure describes agility relative to unit size.

For example, GE's product page cites roughly 50 MW/min for a roughly 57 MW LM6000, while its 430 MW 7HA.03 factsheet lists 75 MW/min. The frame turbine adds more megawatts each minute, but the aeroderivative can traverse a much larger share of its rating over the same interval. Siemens Energy's 440 MW SGT6-9000HL, at 85 MW/min, further shows that modern frames can provide very large absolute ramps.

Also separate:

• Start ramp from zero: includes purge, acceleration, synchronization, and loading.
• Online load-following ramp: movement between two synchronized load points.
• Whole-plant ramp: includes steam production, duct firing, emissions systems, and auxiliary loads.
• Sustained reserve delivery: whether the unit can hold the awarded output for the market's required duration.

A turbine that is offline provides no synchronous inertia or governor response until it is synchronized. All synchronized gas turbines contribute physical rotating inertia, but the response available from an online unit depends on controls, headroom, grid code, and operating point. A battery can cover the pre-synchronization gap; the turbine cannot.

Efficiency: Heavy-Duty Wins Combined Cycle, Not Every Simple-Cycle Comparison

The strongest current case for a large heavy-duty turbine is combined-cycle efficiency at scale. GE's May 2025 7HA factsheet lists 63.9% LHV net efficiency for a 640 MW 1x1 7HA.03 plant and more than 64% for a 2x1 plant. Siemens Energy lists more than 64% for its 655 MW SGT6-9000HL combined-cycle configuration.

In simple cycle, the category gap can be small or reversed by the exact products selected. GE lists 41.0% for the LM6000 PF+ SPRINT and 43.3% for the much larger 7HA.03. Mitsubishi lists 36.7% for the 60 Hz FT8 MOBILEPAC, where mobility and deployment speed—not maximum heat-rate performance—shape the package.

Part-load economics can favor modular aeroderivative plants because operators can shut down complete units and keep the remaining modules nearer their efficient operating point. A large frame may avoid a start by parking at low load instead. GE lists a 15% plant minimum load for its 2x1 7HA configurations and 26% for a 1x1 7HA.03 in the May 2025 sheet. The better outcome depends on power price, fuel price, minimum run time, start cost, emissions, and forecast error.

Compare efficiency only on a common basis:

• simple cycle versus simple cycle, or combined cycle versus combined cycle;
• net versus net and LHV versus LHV;
• the same ambient temperature, elevation, inlet and exhaust losses, and fuel;
• the required load range, not only ISO base load; and
• the same emissions and power-augmentation scope.

Cycling and Maintenance: Replace the Category Myth with the Service Contract

Aeroderivatives generally make frequent cycling easier to plan because their cores are modular and can be exchanged for depot maintenance. GE states that its aeroderivative solutions can perform short 15-minute cycles several times per day without affecting maintenance intervals, and that an aero engine can be replaced in a few days for major inspection. Those are GE fleet claims, not a universal promise for every aeroderivative, combustor, fuel, or service agreement.

Heavy-duty maintenance is commonly governed by factored fired hours, factored starts, or equivalent-base-hour concepts. GE's GER-3620P explains how operating mode, fuel, starts, trips, load severity, and other events can alter inspection planning. The previous version of this article reduced that model to one generic EOH equation; that was too broad because factors vary by frame and service regime.

New frame designs also account for cycling. Siemens Energy describes fast cold starts and hot restarts for the HL class, lists 33,000 equivalent-base-hour service intervals, and has selected the SGT6-9000HL for a new simple-cycle peaking project scheduled for commercial service in 2029. Heavy-duty no longer means baseload-only.

The real maintenance trade-off is:

• Aeroderivative: potentially shorter site outage through engine exchange, but dependent on access to a lease or spare engine, transport, depot slots, and exchange-pool terms.
• Heavy-duty: more work performed in place, larger lifting and outage scope, but longer intervals may fit high-hour duty and the plant avoids maintaining a rotating spare pool.

Model starts, hours, trips, fuel, inlet condition, water or steam injection, and load transients using the exact OEM maintenance document and LTSA offered for the project.

Where Aeroderivatives Usually Have the Stronger Case

Fast-start reserve and renewable firming

When the capacity must remain offline and reach full output inside a five- or ten-minute market product, selected aeroderivatives have the clearest published fit. Check breaker-closure time, minimum emissions-compliant load, and sustained reserve duration—not only full-load time.

Modular onsite and data-center power

Several smaller units can provide N+1 redundancy and allow capacity to grow by module. Compact packages also suit constrained campuses. However, a gas turbine is not a substitute for no-break power: UPS or battery systems must carry critical load through detection, starting, synchronization, and transfer.

Offshore power and mechanical drive

High power density and lower package weight are valuable on platforms, FPSOs, and LNG or pipeline facilities. Free-power-turbine designs can also match variable-speed compressor duty. API or project specifications, fuel quality, salt ingestion, and maintenance access may outweigh grid-style start metrics.

Mobile, temporary, and emergency generation

Mitsubishi's FT8 MOBILEPAC demonstrates the packaging advantage: dual-frequency operation, road-transportable modules, limited foundation requirements, and a stated 10-minute cold start. Deployment time, permitting, fuel supply, interconnection, and emissions equipment still determine when electricity is actually available.

Where Heavy-Duty Turbines Usually Have the Stronger Case

Large combined-cycle blocks

When the plant will run many hours and fuel cost dominates, the efficiency and scale of H- and J-class combined cycles are difficult to match with smaller modules. Fewer gas turbines can also reduce duplicated auxiliaries and maintenance events per installed gigawatt.

Large industrial steam or district heat loads

A frame turbine's larger exhaust flow can support major process-steam or district-heating demand. CHP value must be based on the site's hourly heat profile; an oversized steam system can erase the apparent efficiency advantage.

Hundreds of megawatts of peaking capacity

A simple-cycle frame can provide a large block with one turbine and generator. Siemens Energy's June 2026 announcement for the 420 MW Bristow peaking project is current evidence. The trade-off is a larger single contingency and less modular turndown than a multi-unit aero plant.

Battery Hybrid: Useful Architecture, Not an Aeroderivative Requirement

GE Vernova's LM6000 Hybrid EGT combines a 10 MW battery with turbine controls. The battery can provide immediate frequency response, voltage support, or contingency reserve while the gas turbine remains offline; the LM6000 then reaches full power in five minutes. Southern California Edison installed the first systems at two sites in 2017.

The architecture can reduce fuel burn associated with holding a turbine online for reserve. Its economics depend on the reserve product, required duration, battery degradation, interconnection limit, state-of-charge management, and whether the thermal unit can reliably start before the battery's committed energy is exhausted.

The concept is not exclusive to aeroderivatives. A battery can bridge any thermal start, but a longer bridge requires more usable energy. Compare the complete hybrid plant, not the battery and turbine as separate assets.

Decision Matrix

What to Put in the RFP

1. Define each start: hot, warm, and cold command-to-sync, command-to-minimum-load, command-to-full-GT-load, and command-to-full-plant-load.
2. Define each ramp: MW/min and percent/min after synchronization, down-ramp, load range, hold time, and number of daily events.
3. Request emissions during transients: time to emissions compliance, startup mass emissions, minimum environmental load, and SCR or diluent assumptions.
4. Use a common performance basis: net LHV output and heat rate at ISO and site conditions, including inlet, exhaust, auxiliaries, degradation, and emissions equipment.
5. Provide the dispatch trace: annual starts, hours per start, load histogram, trips, reserve calls, ambient profile, and fuel-switching events.
6. Price the maintenance regime: factored starts or hours, inspection intervals, exclusions, parts-life assumptions, depot slots, exchange engine, lease pool, and transport.
7. Test redundancy: largest single contingency, N+1 requirement, common auxiliaries, black-start sequence, and grid-restoration role.
8. Model the whole plant: HRSG, steam turbine, bypass stack, water use, fuel compression, inlet cooling, transformer, interconnection, and BESS.
9. Set acceptance tests: which code and corrections apply, who measures start time and ramp, and what liquidated damages attach to a miss.

Use our gas turbine comparison tool to screen output and efficiency, then obtain site-specific curves and contractual guarantees for the shortlisted configurations.

Conclusion

The aeroderivative-versus-heavy-duty decision is no longer a contest between a fast peaker and a slow baseload machine. Current heavy-duty turbines can start and ramp quickly, and an aeroderivative loses much of its headline start advantage when the project adds a steam cycle.

Start with the required block size and dispatch trace. Compare the same plant boundary, normalize ramp rates, price factored maintenance, and evaluate net efficiency over the actual load and ambient profile. The winning configuration is the one that meets the grid product and lifecycle economics—not the one with the fastest isolated datasheet number.

Manufacturer and Standards Sources

1. GE Vernova – LM6000 Product Factsheet, September 2025
2. GE Vernova – 7HA Product Factsheet, May 2025
3. GE Vernova – 7HA.03 Factsheet, November 2025
4. Siemens Energy – SGT-A05 Product Page
5. Siemens Energy – SGT6-9000HL Product Page
6. Siemens Energy – Bristow SGT6-9000HL Peaking Project, June 2026
7. Mitsubishi Power – FT8 MOBILEPAC Product Page
8. GE Vernova – LM6000 Hybrid EGT
9. GE Vernova – Aeroderivative Operating Flexibility Whitepaper
10. GE Vernova – GER-3620P Heavy-Duty Gas Turbine Operating and Maintenance Considerations
11. ISO – ISO 2314:2009 Gas Turbine Acceptance Tests