Benson® technology

Highly efficient, flexible and reliable technology for steam generation

Benson technology is a proven process for large-scale steam generation in power plants. The heart of this process is the once-through principle. Combined with sliding pressure operation, this allows for highly efficient, flexible, and reliable power plant operation. Our Benson technology and our associated Benson license will improve your specific steam generator and, consequently, benefit your power plant performance. Find out more below or contact us.

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MPS journal article

New Benson evaporator for vertical HRSGs exceeds expectations

A new Benson HP evaporator design for vertical-exhaust-gas-flow heat recovery steam generators – deployed for the first time in the 24 HRSGs of the Siemens Energy H-class Egypt Megaproject – has proved highly successful. Commissioning and operation have been trouble free, thanks to innovative design features and simulation-based prior optimisation of the all-important Benson-specific feed-water controller. 


Benson technology

Experience and expertise

Since 1933 leading steam generator manufacturers have constructed Benson steam generators worldwide under Siemens Energy Benson license. Today, our Benson technology is widely used in fired steam generators and heat recovery steam generators (HRSGs) of highly efficient modern power plants.

Superior technology for the latest power plant applications

Today combined cycle gas power plants need to be more efficient and flexible than ever, because they have to both

  • Cover peak loads and
  • Serve as backup reserves for renewables

This is where Benson HRSGs make an important contribution. The unique once-through design enables fast flexible start up of a combined cycle, while maintaining high cycle efficiency. Benson HRSGs can be constructed either horizontally or vertically and will fit into any power plant architecture.

Benefits compared with drum-type steam generators

  • Steam parameters can be increased because there is no pressure limitation
  • Increased efficiency in part-load operation and at high ambient temperatures, thanks to reduced attemperator flows compared with a drum-type HRSG
  • Increasing operational flexibility: no limit on gas turbine load transients during startup and load changes, and no limit on load transients for possible duct firing

The first combined cycle power plant with a Benson heat-recovery steam generator (HRSG) – the 390-MW Cottam CDC, located in Great Britain – was successfully commissioned in 1999. More than 100 Benson heat-recovery steam generators have been commissioned to date or are currently under construction.

Supercritical pressure for maximum efficiency

The overall efficiency of a steam power plant counts in every respect, whether it’s reducing emissions or increasing economic efficiency. The best way to boost efficiency is by selecting high steam parameters. The once-through principle permits steam generation even at supercritical pressure. To date Benson boilers have been built for pressures up to 310 bar.


Contribution to flexible power plant operation

The Benson steam generator is especially well suited to flexible sliding-pressure operation: A steam power plant with a Benson steam generator can sustain load transients of four to six percent per minute over a wide power output range. High plant efficiency is ensured even at part load.


Sophisticated construction ­– individually optimized

Benson steam generators can be precisely adapted to suit your firing conditions: Different furnace sizes and geometries can be used depending on the fuel used. An important factor here is that the functions on the water/steam side are not restricted. Benson steam generators have been constructed with the broadest possible range of firing systems, including fluidized bed combustion.


Lately, the Benson steam generator with vertical rifled tubes has been successfully established in the market. Based on the Benson Low Mass Flux Design, this type of steam generator combines outstanding operating characteristics with low investment costs and high levels of reliability.


More than 1,300 Benson fired steam generators have been commissioned to date.

Start with something good – and make it even better

Benson steam generators have outstanding operating characteristics and are extremely reliable – thanks to continuous research and development. And we are refining the technology even more: We’re working intensively to optimize the heat transfer, pressure drop, and flow stability of two phase flows in evaporator tubes. Siemens Energy has its own Benson test rig for the trials. The results of the trials have led to the creation of the world’s largest database on heat transfer and pressure drop in evaporator tubes, and support the development and validation of the Siemens Eenrgy Benson design software.


Another key area of focus is the development of Benson-specific control concepts, which make a key contribution to ensuring the best possible operation of your particular system.

Siemens History

History of the Benson Licence

In 1925, Siemens acquired the right to use Benson's patent, and in 1926–27 the first large Benson boiler in Berlin-Gartenfeld was built. Siemens improved the technology and developed it as an internationally acknowledged standard for large steam generators. In 1933, Siemens decided that it would no longer manufacture steam generators in its facilities, but would instead award licenses based on its own patents and expertise. This story goes still further:

License and services by Siemens Energy

A profound package

The Siemens Energy Benson license is available for fired steam generators as well as for heat-recovery steam generators. It primarily addresses the thermodynamic and thermo-hydraulic design of the evaporator system in Benson steam generators. 

Basically, the license comprises the following components:


  • Use of Siemens patents for the construction of Benson steam generators
  • Use of specifically developed and highly specialized Benson design software
  • Training and consulting
  • Transfer of the latest findings from research and development


In addition to providing the Benson license, we also advise utilities on questions related to the evaporator system of once-through steam generators.


A selection of our projects around the world

Give your steam generator a boost. Benson technology will make the difference: and we’ll find the right solution for your needs.

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