Flexible plant operation

Steam turbines under robust conditions

Reliable power generation equipment for years of operation

Compared to a steam turbine, which is evenly driven with the same load in steam power plants, a flexible operation, as is usual in decentralized power generation from renewable energies or in industrial sectors such as palm oil production, reduces the life of a turbine tremendously. However: Siemens steam turbines are designed for 200,000 operating hours.

Some mill operators produce only for six months a year, but re-start the power plant equipment on a daily basis and operate it for ten hours After 60 years of operation this exemplary mill operator would have accumulated about 108,000 operating hours. Maintenance intervals for steam turbines with many starts and stops are recommended after every 1000 starts, inspections should take place yearly. The mill owner in this example would, thus, be recommended to have a major overhaul interval  to schedule a maintenance cycle every five years.*



*) All numbers mentioned are an average value exemplary and depend on particulate model and specific operating condition. and must be re-evaluated according to customer-specific conditions. Given numbers of 1'000 start are exemplary and may change depend on actual operating condition


The art of engineering: most crucial parts

Load changes and the increased number of start-stop cycles cause thermally induced stresses, which are a challenge for every steam turbine.

Large thermal stress especially arises at the start of the turbine when incoming steam with temperatures higher than 450 ° C hits the components some of which, e.g. the inner parts heating up faster than others. Changes in the design of the Siemens steam turbines therefore aim on fast heating of the turbine to enable fast heating through and eventually fast start times. For example, the casing design with a small wall thickness is designed for such frequent starts.

Also, the low-pressure blades are exposed to high mechanical stress when the steam turbine is started and stopped frequently. Especially the blade feet are crucial. At up to 10,000 rotation speed per minute and higher, tremendous centrifugal forces of several tons are generated and the blade tips may reach supersonic speeds.

Siemens has decades of experience with steam turbines, which are frequently started. As the market leader in the field of steam turbines for solar thermal power plants, Siemens has been supplying turbines that are operated flexibly on a daily basis since the 1980s. Decades of experience in numerous solar projects has given our engineers important insights into how the blade design for such turbines must be designed and what thermo-mechanical stress arises.

The blade design is adapted to high mechanical stress due to frequent starts

All parameters of the operation are continuously monitored by the turbine control systems. It regulates the operation of the steam turbine and gives feedback on the thermal load and effects on the service intervals, which arise due to flexible driving.


A perfect fit

With thousands of steam turbines in operation, Siemens delivers power trains for a wide range of purposes. For the palm oil industry, turbines of up to 10 MW are the most relevant. Whether you run a small, medium, or large mill, we have the best-fitting and easily maintainable solution to match your needs.

Steam turbine models most suitable for palm oil mills are the SST-200 and the D-R R/S:


More than 100 years of progress

The more than 100-year history of our steam turbines is marked by change.

This change is not only driven by our own engineers engaged in research and development, but also by changes in the markets. Numerous acquisitions and mergers with various brands have changed the design of our steam turbines again and again.

However, with every single acquistion,  Siemens harmonises the various technical components of a steam turbine by combining all well proven technical features from the several product lines in one common basis.


Biogas substitutes fossil fuels in Swedish test center

While we support hundreds of customers to get the most out of their biomass fuel, we strive to get closer to decarbonization ourselves. The first delivery of biogas has now arrived at Siemens in Sweden.  The good news: our fuel-flexible gas turbines can now be tested fossil-free. How? Watch our video.