Limmattal Energiecentrum (LEZ)

Industrial area
Urban design plan
Spatial quality plan
Public space design

Zurich | Switzerland

Waste management and water treatment are essential functions that keep society running, yet they rarely take centre stage. For Switzerland’s Limmattal region, they became the starting point for an ambitious design vision. With the Limmattaler Energiezentrum (LEZ), ECHO Urban Design, together with Baukunst, Rapp and Malheur & Fortuna, developed a vision for the future that transforms Limeco’s existing waste-to-energy plant and wastewater treatment facilities into a compact, future-proof energy centre. A place where circularity, energy production and ecological development come together.

The starting point for the vision was concrete: the existing waste treatment facility needs to be replaced, while the water treatment facilities require expansion. But the challenge soon grew into something larger. The development presented an opportunity to make a broader contribution to the energy transition and to the region’s ambition to become climate-neutral by 2050. The new energy centre must accommodate future technologies and evolving energy needs, while minimising its impact on the landscape, nature and surrounding environment as much as possible.

Client:	Energy company LIMECO
Design:	2022
Type:	Urban & landscape plan
Status:	Competition test planning
Program:	Sustainable energy centre, water treatment facility & ecological landscape
Partners:	BAUKUNST, Rapp AG, Malheur & Fortuna

Design and spatial development

The design is based on the principle of densification. Rather than expanding the building footprint, the various technical functions are brought together within a compact spatial structure. By stacking installations, partially embedding elements of the building, and intelligently reusing existing structures, the spatial footprint is minimised, creating more room for nature, water and public functions.

The waste-to-energy plant, wastewater treatment facilities, energy plant and supporting functions are integrated into a single coherent system. The various components are organised to ensure efficient logistical processes and minimise distances between functions. At the same time, this creates a clear and robust spatial framework capable of accommodating future expansions and technological developments without altering the identity of the site.

The location of the LEZ between the existing industrial areas, the urban development of Dietikon and the nature reserve along the Limmat River is a key starting point for the design. The energy centre acts as a link between these different worlds, making the transition between landscape, infrastructure and city visible and tangible.

Use and civic function

The new LEZ is more than a technical facility. The design makes energy production, waste processing and water treatment visible to residents, visitors and users of the area. Where such facilities traditionally disappear behind fences, the LEZ embraces openness and accessibility. The complex presents an active frontage towards Silbernstrasse, with access to a publicly accessible indoor environmental centre. The square can be used flexibly for a range of activities. From this side, a long staircase provides access to the roof of the plant. A footbridge then leads to the existing chimney, which is transformed into a panoramic viewing platform overlooking the river at a height of 65 metres. On clear days, Lake Zurich, located 12.5 kilometres away, is clearly visible.

A network of new walking routes, visitor paths and viewpoints connects the site to its surroundings. Green roofs, places to stay and a visitor centre allow people to experience the processes behind the energy transition at close range. Educational programmes, exhibitions and guided tours contribute to raising awareness of circular systems and the sustainable use of resources.

The design also allows for temporary and complementary functions. Within the flexible structure, workspaces, research facilities, event spaces and other public programmes can be added in the future. In this way, the energy centre becomes not only a facility serving the region, but also an active part of everyday life.

The Limeco complex is located along the Limmat River and the Reppisch mountain stream. Several nature development projects are already underway, particularly along the Limmat. The Reppisch is currently a channelised mountain stream that runs through Dietikon before joining the Limmat alongside the site. The stream forms an important ecological corridor, facilitating the exchange of species between the mountain and river ecosystems. The LEZ’s exceptional location along these potentially high-quality ecological corridors has been embraced by designing the complex as an integral part of the highly dynamic river landscape.

Ecology, climate adaptation, circularity and energy transition

A key principle of the design is to strengthen the landscape and ecological qualities of the area. By organising the technical installations compactly, space is created for new nature zones and water structures along the edges of the site. The site is transformed into a new ecological habitat, in which existing basins and structures are repurposed for water retention and nature development. The building itself also becomes part of the green network through its green roofs. Together, these new habitats for birds, insects, amphibians and small mammals strengthen the connections between the natural areas along the Limmat and increase biodiversity.

By reusing existing foundations and retaining underground structures and infrastructure wherever possible, disturbance to the soil and water system is minimised. At the same time, historic structures that contribute to the identity of the site are given new meaning.

The LEZ forms an important link in the transition towards a circular and climate-neutral energy system. Waste and wastewater are no longer regarded solely as residual streams, but as valuable resources for the production of energy and raw materials. The design accommodates innovative technologies such as district heating networks, biogas production, energy storage, Power-to-Gas systems and future carbon capture technologies. In addition, the reuse of existing buildings and structures reduces material consumption and CO₂ emissions.

Logistical processes are optimised as well. By consolidating material flows and making renewed use of the existing railway connection, the impact on the surrounding area is reduced, while limiting the pressure on natural areas and residential neighbourhoods.

Ecological and recreational water treatment

Flexible urban square for events and reception

Ecological roof with walking route and viewing platform

Process and collaboration

The design vision for the Limmattaler Energiezentrum was developed in collaboration with Limeco, the participating municipalities, experts, environmental organisations, and a range of design and consultancy partners. The project called for an integrated approach in which energy, water, waste management, landscape, ecology and urban development were considered as a single system from the outset.

The result is a future-proof energy centre that goes beyond a traditional infrastructure project. The LEZ demonstrates how technical infrastructure, nature development and public space can reinforce one another.