Construction work has commenced on an energy storage project utilising three-megawatt ultracapacitors at PVO-Vesivoima's Kierikki power plant. This is PVO-Vesivoima's first project of its kind, piloting energy storage technology that extends the power plant's lifecycle. The short-term energy storage, set to be completed by the end of the year, addresses the growing need for rapid balancing power.

“Construction related to the ultracapacitor began in the second week of September at the Kierikki power plant site. This autumn, two shipping containers, each housing 1.5-megawatt ultracapacitors, will be installed near the switchyard. The installation work is expected to be completed, and the energy storage ready for use in December”, says Markus Pyykönen, the project manager from Pohjolan Voima. 

The ultracapacitor system is supplied by the German company Freqcon GmbH. The Finnish company Insta Automation will provide the main electrical systems for the energy storage, a new main transformer, and related electrical work. 

Ultracapacitor enhances regulation capability and extends lifecycle 

The ultracapacitor is a highly efficient short-term energy storage device operating in conjunction with a hydropower plant. It is an electrostatic device that can deliver power in less than a second. The ultracapacitor stores electricity and releases it quickly into the grid for a few minutes. Together with the hydropower plant, the energy storage supports the reliability and operational security of the electrical system by enhancing the ability to provide the balancing power needed for the growth of renewable energy. 

“In addition to improving regulation capability, the ultracapacitor also extends the lifecycle of the hydropower plant in the long term. The ultracapacitor meets the need for rapid regulation first, in milliseconds, reducing the need for very rapid turbine control movements and thus saving the turbines from mechanical wear”, says Antti-Pekka Sipola, the operations manager at PVO-Vesivoima. 

The ultracapacitor being piloted in Kierikki will gather practical experience for a potential larger investment. 

“The ultracapacitor in Kierikki is an important pilot project for us, from which we will gain practical experience and information for possible similar investments in the future. We aim to deploy ultracapacitors at all our hydropower plants in the future,” says Antti-Pekka Sipola. 

The ultracapacitor being built in Kierikki will not have a significant impact on water flows or the use of the power plant’s water system. 

Illustration: The ultracapacitor will be located near the switchyard of the Kierikki power plant. Two shipping containers will house ultracapacitors with a total capacity of three megawatts, along with auxiliary systems. The equipment will be connected to the power plant’s electrical system via cables.