The Hepokorpi substation is located between the popular Oittaa outdoor recreation area and Ring III. Due to its prominent location and the town plan's requirements, exceptional attention has been paid to the architecture and construction quality of the substation and the landscape pylons. The substation's colours, materials, and form are based on the site's forest landscape.
When completed, the Hepokorpi substation will be the largest in Finland. It will consist of 400 kV and 110 kV indoor gas-insulated switchgear, two 400 kV transformers, and three designer powerline pylons. It will serve the local electricity grid and a large data centre nearby. The recovered waste heat from the data centre will be used for district heating in Espoo.
The Hepokorpi facility will be Finland's first substation with main equipment spaces in prefabricated solid wood. The columns and beams in these rooms are made of glue-laminated timber, with wall and roof elements in cross-laminated timber. High-quality in-situ concrete structures complement the timber structures.
The exterior architecture is inspired by the surrounding landscape. The dark green glazed ceramic cladding of the façade in varying shades refers to the forest and the site's topography. The double façade construction allows for large window surfaces, protected by the ceramic cladding, which is also a safe solution for the area's birdlife.
The hyperboloid structures of the landscape pylons are part of the mathematical landscape of the power lines crossing the site. Their spatial and architectural form aims to harmonise with the abstract architecture of the new buildings.
