Finnish construction company YIT and AFRY Finland have secured a contract worth €75m to construct a seasonal heat storage in Vantaa, Finland for Vantaa Energy using the alliance model.

The companies will jointly plan the work and implementation of the project to match Vantaa Energy’s goals and determine the target cost as well as the incentive scheme during the development phase.

Vantaa Energy will plan the implementation of the investment and the transition to the implementation phase at the end of the project development phase.

During the implementation phase, YIT and AFRY Finland will be responsible for the construction of what is claimed to be the world’s biggest seasonal heat energy storage underground.

The size of the facility will be about one million cubic metres and will have around 90 gigawatt hours of capacity.

YIT stated that the seasonal heat storage is the most important part of Vantaa Energy’s Fossil-free 2026 project, with which the company aims to completely stop usage of fossil fuels by 2026.

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By GlobalData

The development phase of the project is scheduled to begin in this summer with construction planned in autumn 2022.

Furthermore, work on the contract is anticipated to be concluded in 2026.

Vantaa Energy managing director Jukka Toivonen said: “The seasonal heat storage is a key part of our innovative investment programme that combines new technological solutions and allows us to phase out fossil fuels in energy production as quickly as possible.

“We chose the flexible alliance model for the implementation of the demanding design and construction project, and I am convinced that together with our partners YIT and AFRY, we will be able to implement the project efficiently so that the outcome will – at the minimum – meet the strict goals set for it.”


YIT and AFRY Finland win contract to build seasonal heat storage in Finland. Credit: YIT Corporation.