Tammisto Electricity Substation / Kivinen Rusanen Architects

Architects: Kivinen Rusanen Architects
Area: 1705 m²
Year: 2023
Photographs: Tuomas Kivinen, Max Plunger
Lead Architect: Tuomas Kivinen
Design Team: Anna Blomqvist, Maria Karjalainen
Client Project Manager: Jarmo Henttinen
Client: Fingrid Oyj
City: Vantaa
Country: Finland

Tammisto Electricity Substation infrastructure project designed by Kivinen Rusanen Architects in Vantaa upgrades Finland’s main grid by replacing outdated equipment with a new 110 kV gas-insulated switchgear system, improving safety and capacity while allowing for future expansion. The project includes new structures, fences, backup systems, and landscaping, with phased construction ensuring uninterrupted grid operations. The new building integrates into its urban context and aligns with Vantaa’s town plan, using warm-toned water-struck brick facades that reference the adjacent residential area and the historically protected 1947 substation designed by Aarne Ervi. The design adopts the scale and composition of this older building, using triangular cuts in the massing and four distinct masonry patterns supported by a steel frame over prefabricated concrete. The use of 13 custom brick types and detailed 3D modeling enabled precise facade execution. Natural light enters through double-skin lattice masonry walls offset from internal glass walls, fulfilling safety and privacy needs. Two 1980s transformer bunkers were updated with Umbra-treated concrete to unify the visual character of the site, which also includes forest patches and transmission infrastructure. The architectural approach connects utility infrastructure to material refinement, spatial coherence, and a warmer public presence.

Tammisto electricity substation / kivinen rusanen architects

The Tammisto Electricity Substation site in Vantaa has functioned as a central power grid hub for the Helsinki metropolitan area for decades. The oldest systems on the site required modernization to enhance their reliability, capacity, and safety. To address this, Fingrid Oyj, the Finnish main grid operator, constructed a new building to accommodate a 110 kV Gas-Insulated Switchgear (GIS) system, replacing the extensive and aging air-insulated switchyard. The project scope also involved the installation of new powerline structures, perimeter fences, a backup power generator, extensive landscaping, and the planting of new greenery. The construction process was carefully phased to reduce interruptions to ongoing substation and grid operations and to ensure a smooth transition. In addition, the project was designed to support future expansion of the substation’s capacity, preparing it for increased electricity demand.

The architectural objective was to create a unified appearance across the new and recently upgraded buildings and structures on the site, aligning with the goals and regulatory requirements of Vantaa City’s town plan. The design of the new substation building was intended to harmonize with the historic former substation and the surrounding residential area, using facades composed of water-struck bricks in a dynamic range of warm tones and textures. The site, situated near major transportation corridors, commercial zones, residential neighborhoods, and Helsinki Airport, is secured by a perimeter fence and controlled access gate to restrict entry. It comprises multiple buildings and structures, each with distinct characteristics. The oldest and most prominent of these is the former substation designed by Aarne Ervi in 1947. This building is a long, low structure with a tall transformer tower at one end, detailed red brick facades, and a tile-covered gabled roof. It has since been repurposed as an office and is now protected under municipal zoning regulations. Other facilities on the substation site include a 400 kV switchgear building, transformer bunkers, open-air switchyards, and various power transmission structures. In addition, the property contains tall trees and areas of preserved forest.

The architecture of the new substation building was designed to establish continuity with the old substation through its scale, massing, and facade materials. It was also intended to correspond with the scale of the surrounding residential area. The two-part composition of the historic substation served as inspiration for the triangular cuts introduced into the new building’s massing. These cuts define three longitudinal sections within the building. At both ends are zones that provide access to the structure and house facilities that manage or support its operations. The central section contains the main process equipment and cable rooms. The building is organized across two stories, with service areas on the ground level and the GIS and control rooms occupying the second floor. The machine room is positioned above the control room. The facades are constructed using water-struck bricks laid in four distinct masonry patterns, emphasizing both the massing and spatial organization of the structure. Executing these patterns around right-angle, tight-angle, and wide-angle corners and openings required the use of 13 different custom brick types. Detailed 3D models of the brick facades were developed to generate drawings for each brick type, and the supplier created specific molds for all of them. The building’s structural frame is composed of prefabricated concrete, while the double-skin facades are supported by a steel frame placed within the cavity.

The south and north sections of the building receive natural light through double-skin walls made of lattice masonry, positioned approximately one meter away from full-height glass curtain walls. The central section does not include windows, but the main equipment room benefits from indirect natural light entering through the adjacent end spaces. The lattice masonry allows daylight to pass through while meeting the client’s safety requirements and blocking direct views into the substation from the outside. The design brief also included the renovation of two concrete transformer bunkers from the 1980s. Their facades were finished with Umbra color patination, a treatment in which the chemical agents penetrate the concrete surface and react with the cement to produce reddish-brown, rust-like tones. The combination of varied yet complementary reddish bricks on both the old and new substation facades, along with the earthy, rusty hues of Cor-Ten steel and Umbra-treated concrete, gives the site’s structures a cohesive and warm appearance. The new substation building is positioned on the western edge of the site, allowing the existing switchyard and power lines to remain operational during the construction phase. After the technical installations were completed, the old air-insulated switchgear was decommissioned, and the outdated power line structures were removed. The Tammisto Electricity Substation project aims to present a clear architectural identity for sustainable urban infrastructure. It supports the process of electrification, ensures a dependable power supply, and seeks to enhance the visual and cultural character of both the site and its surrounding environment.