Seasonal heat storage, Vantaa, Finland
We built a new dam on Lake Mjåvatn to replace the old dam built in the 1940s. In addition to building the dam, YIT will also excavated a tunnel in the area that is about 500 metres long.
The new dam is approximately 100 metres long and 11 metres high at the highest point. When the new dam was finished, the old one was demolished and part of the water was channelled into a tunnel we have excavated for it to reach a powerplant down by the stream.
The 500-metre tunnel was excavated quickly due to the site closing for the winter season. For the same reason concrete work has been made faster with a good collaboration with people working in the tunnel.
Mjåvatn is located in the middle of a National Park, so everything was restored to its original condition when the project is wrapped up. The new dam does not have an increased impact on the environment, as it will replace the existing decades-old dam. The river will have calmer waters and less fluctuation in depth. What’s more, people will benefit from the roads being kept in better condition because the tens of dams in the area need to be accessible for service and maintenance.
The customer E-CO Energi is the second largest energy producer in Norway and is owned by the City of Oslo.