The application of EU2016/631 RfG or VDE4105-4120 for Howden KK&K Steam Turbines

Monday, 25 July 2022




The energy transition is shifting power generation from a few large power plants to numerous small and decentralized systems.

In Europe, to ensure that electricity grid stability is maintained, EU2016/631 regulations have been developed for implementation throughout the European Union.  Now that these regulations have  been incorporated into European national standards VDE4105 – VDE4120, there are three ways to ensure networks conform to these regulations:

  • A unit certificate for machines,
  • A prototype process that also leads to a unit certificate,
  • Individual verification procedure for each machine.

Typically, the certification is performed by a third party.

With these certification procedures, manufacturers, plant operators and grid operators are now faced with additional responsibilities and workload. This is especially the case with customer-optimized, smaller steam turbines where the certification process can also be a commercial challenge.

The Howden KK&K steam turbines are often used to convert residual steam into electricity, as a reducing station in the likes of heating networks or biomass plants. In order to generate maximum power out of the customer process parameters such as steam volume and steam pressure, each machine is designed and optimized according to that customer’s specific requirements.

For these types of turbines, the only reasonable way of certification is through Option 3, the individual verification procedure. The additional costs caused by this, which do not add value, can amount to up to a third of the total machine costs, representing a significant economic burden.

Why is individual verification so costly? There are two major challenges for this approach, namely the technical requirements of all the components and the procedural coordination of many participants in the process. The technical requirements are usually met by two or more components, which often come from different manufacturers and consideration of the interaction of these components is essential, especially in the evaluation of dynamic processes.

In the procedural coordination there is a requirement to show how all those involved - from network operators, plant users, manufacturers, numerous suppliers, test laboratories to accredited certifiers – work together in order to bring the process to a successful conclusion.

By mastering this complex process, system certification is possible for individual customer-optimized steam turbines.

Latest News


Howden has won Impact Individual Achievement of the Year at the Hydrogen Impact Investment Awards 2022.


Howden screw compressors aid vapor recovery in first of its kind floating production system; Howden contributes to emission control in Gulf of Mexico


Howden has appointed Mark Courtney as Global Market Director of CCUS.

Bright Futures

Howden has signed a national partnership with PRIMARY ENGINEER® to bring engineering into classrooms across Scotland. This new partnership is only one of two in the Scottish region, which will play an important role to link schools into industry partners.

Bright Futures

After meeting with some of the team from May We Help, the Fairfield Bright Futures volunteers decided to use their engineering skills to build sensory chairs for children with autism and PTSD.


Howden supplies compressors to Tuas Water Reclamation Plant

If you would like to submit an enquiry please get in touch.