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3 min read

Uniper, UK: Repurposing retired generators to provide essential grid stability services

Killingholme power station converted two retired steam turbine generators to synchronous condensers with flywheels to provide carbon-free grid services.

The challenge: Repurpose the retired steam turbines and generators

Commissioned in 1992, Killigholme has a rich history of innovation and is home to one of the biggest gas-fired power plants in the UK. As one of the leading power producers in the UK, Uniper has always delivered grid stabilizing services. When the country’s grid system operator, National Grid ESO, launched the Stability Pathfinder project, Killingholme was identified as a prime site for Uniper to provide dedicated grid stability services. For this, Uniper sought to repurpose steam turbine generators decommissioned after the power station was converted from a combined cycle plant to an open cycle plant in 2017.

The solution: Convert the generators to Rotating Grid Stabilizers and add flywheels

A team of engineers from Uniper and Siemens Energy came together to work on this project amidst the COVID-19 pandemic. Converting an existing generator and retrofitting a flywheel was a first-time project for both teams. Therefore, working closely as one team was essential in developing a bespoke solution for the Killingholme power station.

The team removed the steam turbine and reused the generator as a grid stabilizer. Then they added a flywheel in place of the turbine to provide maximum inertia. This conversion provides much needed services to the grid.

Siemens Energy was responsible for the supply, installation, and commissioning of major equipment including flywheels, auxiliary systems, electrical start-up systems, excitation systems, and protection. The scope of supply also includes the fully redundant Omnivise T3000 control system including vibration monitoring for the synchronous condenser and its implementation into the existing control room. We also provided civil engineering, pipework, and electrical system integration.

Picture of the Killingholme power station

Killingholme Power Station in Lincolnshire, UK

Rotating Grid Stabilizer with a flywheel at the Killingholme power station

Rotating Grid Stabilizer with a flywheel at the Killingholme power station

Learn more about how you can convert your existing equipment to a synchronous condenser with our Rotating Grid Stabilizer conversion solution.


Synchronous condenser operation places high demands on control capabilities for a variety of control modes. The integrated Omnivise controls portfolio covers these requirements and supports grid stabilization.

The benefit: Provide carbon-neutral grid services and introduce more renewable energy sources

Today's power system requires frequency and voltage management to avoid power supply disruptions. Rotating Grid Stabilizer with a flywheel supports this need by providing maximum inertia, short circuit power and reactive power, without burning fossil fuels.

The partnership between Uniper and Siemens Energy has yielded numerous benefits:

  • Making use of retired generators
  • Providing essential grid stabilizing services to National Grid ESO without the need to generate power and proactively supporting the UK’s grid stability
  • Enabling the integration of renewable sources while keeping the grid stable and secure

Do you have any questions?

Please feel free to contact us if you would like to learn more about this reference or Rotating Grid Stabilizer conversion solution. 

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