SBB is transforming the 42,000-square-metre Werkstadt site in Zurich into a vibrant urban space, to be completed by 2035. This will preserve the fabric of its historic buildings, which will one day be joined by both new buildings and extensions to create an exciting cluster. The transformation of the former SBB workshops will be exceptionally sustainable, featuring climate-conscious building measures, circular economy elements and an innovative energy concept.
Developing existing buildings
In close coordination with the monument preservation authorities, the existing buildings will be gradually renovated and joined by new buildings and extensions in the coming years. At the heart of the site, the former carriage workshop ‘Building Q’ will allow for a diverse usage mix under one roof from 2023. The development will offer an exciting interplay between the fabric of historic buildings, structural densification and public use of outdoor space.
Environmentally friendly construction
‘SBB wants to be climate-neutral by 2030, and climate-compatible construction is an important factor in achieving this objective,’ said Gabriele Bühler, Project Manager at SBB. Various climate-conscious building measures have been incorporated into the planning of the site. That includes configuring the new buildings to promote the circulation of cool air currents. Where possible, the roof water will be allowed to seep into an above-ground system for further cooling. Surfaces will remain unsealed where possible. The transformation follows a systemic approach that considers the building along its entire life cycle. The aim is to keep CO2 emissions as low as possible. To ensure circularity, all construction components are recorded on the Madaster platform. There is also a particular focus on reusing components.
Energy concept: 100% renewable
ewz was able to win SBB’s public tender with an energy solution based on 100 per cent renewable energies. Groundwater, which is collected in four wells on the site, serves as a source of heating and cooling. From these wells, the water flows to the energy centres in the larger buildings, which house heat pumps and cooling machines that bring the water to the required temperature. An anergy network connects all the buildings and ensures that excess energy is exchanged between the building groups. For example, excess heat or cold in one building can be used in another. This system also has the advantage of not requiring groundwater boreholes in every building: the smaller buildings are connected to the energy centres via a local heating network. Heating and cooling is generated without any CO₂ emissions, as the rest of the electricity also comes from renewable sources. The use of a monovalent energy system will ultimately lead to a CO2 reduction of over 2,100 tonnes per year.
High self-consumption of solar power
ewz also plans, finances, creates and operates the transformer systems and medium-voltage lines to supply the site with electrical energy. ‘Some of the electricity that the people in the Werkstadt use on the site is produced there using photovoltaics,’ explains Markus Fischer, Head of Sales at ewz Energy Solutions. To this end, SBB and ewz want to make the best possible use of the roof areas for solar power production. Both the roof of Building Q, at the centre of the site, and the roofs of other buildings with a suitable structure and orientation for generating solar power are to be kitted out with photovoltaic systems. SBB requires its tenants on the site to form a self-consumption association (ZEV). ‘When completed, the ZEV will consist of around 300 parties that will use locally produced electricity on the site. This allows us to achieve a high self-consumption rate, which, in turn, makes a significant contribution to the cost-effectiveness of the photovoltaic systems,’ says Markus Fischer. He expects self-consumption on the Werkstadt site to be almost 100 per cent when completed.
The benefits of contracting
For the owner, this form of collaboration has various benefits, including keeping financial risks and management costs very low. If a system fails, ewz makes sure it gets back into operation as quickly as possible. To ensure that the system can be operated efficiently, ewz will start undertaking energy-related operational optimisations shortly after commissioning. As part of an ongoing process, the systems will be optimised and adapted to the actual needs relating to their use. By extension, this ensures that they consume as little energy as possible, generate minimal costs and offer maximum convenience for users.
Werkstadt Zürich is a successful example of a forward-looking approach to repurposing a historic industrial site. With the targeted renovation and expansion of existing buildings and a ground-breaking energy concept, the developers – together with the planners and ewz – are creating added value for future users and the environment alike. Find out more about the Werkstadt site’s innovative energy concept here.
