If rapid startup, cycling, compact size, and separation of the turbine from the main site is needed, then you should select aeroderivative gas turbine. In case you need very large and continuous production of energy, then you should select heavy duty gas turbine. 

Selection of the appropriate turbine will depend on the hours of operation and starting cycles. The table below presents differences between these two types of turbines. 

What Are the Main Types of Gas Turbines? 

Most gas turbines used for power generation fall into two families. 

What Is an Aeroderivative Gas Turbine? 

Aeroderivative Gas Turbine this kind of turbine is based on the jet engine used in an aircraft. It is mobile and made up of modules. Some of the examples of this kind of turbine are GE LM2500 and LM6000, Siemens Energy SGT-A Series, and Mitsubishi FT8. The range of its output power goes from 2.5MW to more than 100MW. 

What Is a Heavy Duty Gas Turbine? 

The frame type gas turbine is used for stationary application only when it is manufactured. The turbine consists of heavy casings and an equally robust rotor amongst other components. Such turbines have power capacities ranging between 30 MW and more than 500 MW; in addition to that, the most sophisticated and largest turbines constitute the core of the combined cycle power plants of today. 

Aeroderivative vs Heavy Duty Gas Turbine: Quick Comparison 

Figures are indicative and vary by model, site conditions and fuel. 

Comparing the Two Turbine Types in Detail 

Start-Up Speed and Flexibility 

Aeroderivatives have a reputation of being capable of rapid startups and ramping capabilities. Aeroderivatives are more tolerant of cycling than the majority of frame units, thus making them ideal for applications where grid systems are being complemented by solar and wind power sources and additional capacity needs to kick in within minutes. 

Efficiency 

In simple cycle operation, the aeroderivative is usually the winner because of its high-pressure ratio, which comes from the aircraft engine design. In the combined cycle, the heavy duty gas turbine is usually the winner because of the higher exhaust temperature, which makes the gas turbine exhaust better suited for use in a heat recovery steam generator (HRSG). 

Footprint and Installation 

Lighter aeroderivative package sets have the advantage that they can be erected quickly, with smaller foundation requirements and easier logistics. This is particularly significant where transportation through roadways is constrained due to locations such as off-shore platforms, islands, mining sites, and distant sites. 

Maintenance and Availability 

Most aeroderivatives run on the swap-out principle, whereby an engine is taken out and exchanged for one that has been rented or exchanged, thereby reducing downtime. The maintenance of heavy-duty turbines is done on-site using combustion, hot gas path, and major inspections, which are based on operating hours and starts. Heavy-duty turbines have the ability to run consistently, whereas aeroderivatives require more specialized maintenance due to their sensitivity to air and fuel. 

Cost per MW 

Heavy-duty turbines are generally less expensive to install on a per MW basis, while also being less expensive on a per MWh basis when used for baseload operation. Aeroderivatives may be more expensive per MW, however due to the flexibility, quick start capability and low installation cost, they could end up being cheaper than heavy duty turbines for peaking and remote duty applications. 

Which Gas Turbine for Power Generation? Use-Case Examples 

Peaking Power 

Aeroderivative gas turbines are usually a great option for grids that require power between a few hundred and a few thousand hours annually because of their rapid startup capability, high ramping speed, and excellent performance at partial load conditions. This is arguably the most common response when asked “what’s the best gas turbine for peaking?” 

Cogeneration and Combined Heat and Power (CHP) 

In cases where steam or hot water is needed continuously in industries such as refineries, paper mills, chemical processing units, or even district heating systems, the system based on turbine with HRSG would have been preferred. Other types of turbines that are common in the range of 1–25 MW capacity are small industrial turbines like Solar Turbine types. The overall efficiency may reach above 70–80%. 

Mechanical Drive 

Compressors and pumps for oil and gas, LNG, and pipeline applications frequently employ aeroderivatives like the LM2500, as well as Solar Industrial Turbines, which provide flexibility in speed as well as power density. Industrial Turbines have the advantage of being very robust and having lengthy maintenance intervals. 

Remote and Off-Grid Sites 

Where cranes, roads, and manpower are scarce, a smaller aeroderivative engine or an industrial package engine will be easy to install. The maintenance of engine swaps requires less manpower. Planning needs to be done for the fuel source and quality of air. 

Baseload and Large Utility Plants 

For plants running 6,000–8,000+ hours a year, large heavy duty turbines in combined cycle are the usual choice thanks to their efficiency, scale and long service life. 

What to Check Before You Buy 

Whether new, refurbished or surplus, verify these points before purchase: 

• Operating profile: annual hours, number of starts and load swings. 

• Site conditions: ambient temperature, altitude and humidity, since output drops in heat and at altitude. 

• Fuel: natural gas, dual-fuel, diesel or syngas, and fuel quality. 

• Maintenance history: operating hours, equivalent operating hours (EOH), starts, overhaul records and borescope results. 

• Support: parts availability, service providers and OEM documentation. 

• Compliance: emissions limits, grid code requirements and import regulations. 

Frequently Asked Questions 

Is an aeroderivative better than a heavy duty gas turbine? 

Neither is better in every case. Aeroderivatives suit fast, flexible, compact or remote applications. Heavy duty turbines suit large, continuous, high-efficiency operation. 

Which gas turbine is more efficient? 

Aeroderivatives often have higher simple cycle efficiency, while large heavy duty turbines achieve the highest combined cycle efficiency. 

Which type is best for peaking power? 

Aeroderivative gas turbines are generally preferred because of their fast start-up and cycling capability. 

Are aeroderivative turbines more expensive? 

Often they cost more per MW at purchase, but lower installation cost and operational flexibility can offset that for peaking and remote projects. 

Conclusion 

Selection of aeroderivative and heavy duty gas turbines is dependent on duty cycle. Determine your operating hours, frequency of starts, site conditions, and heating load, then calculate lifecycle costs. When comparing new or used equipment, a technical evaluation of the equipment and an understanding of your application requirements can reduce costs for you.  

In need of a gas turbine? Our team can assist you with your selection process.