buildings in Guggach
efficiently combined
- 197 apartments in leasehold ownership
- 80 fully equipped charging stations, 200 parking spaces – basic infrastructure
- 1,000 PV modules
- PV system output 464 kWp
- Annual PV production approx. 450,000 kWh
The Guggach residential complex in Zurich consists of four blocks with a total of 197 owner-occupied apartments that enclose a common courtyard. The dark colours of the cast-glass facades lend the seven- and eight-storey buildings an urban character.
When constructing the new development a few years ago, ewz was able to demonstrate in a feasibility study that integrating a photovoltaic (PV) system would make sense. The potential for solar power turned out to be considerable, and the technical implementation was within normal limits. Although the client had decided at the time to build the system at a later date, they had the necessary empty conduits installed.
In 2022, the owners again discussed the topics of solar power and electromobility. Using model calculations, ewz demonstrated that PV contracting would be the most suitable option due to the high investment costs. The contracting model also includes system monitoring as well as professional maintenance and servicing throughout the entire contract term. The installation of the charging stations, on the other hand, was financed by the co-owners.
Since autumn 2024, some of the electricity for households and electric vehicles has been produced on the roofs of the four apartment buildings. The more than 1,000 photovoltaic modules supply around 450,000 kWh of sustainable electricity each year. This corresponds to more than half of the residential development’s total consumption, which comes to around 600,000 kWh, excluding electromobility.
Around a third of the owners expressed a need for a charging station. The installations included 80 parking spaces with full fit-out (standard D ‘ready to charge’). 200 parking spaces were equipped with basic infrastructure (standard C1 ‘power to garage’). Standard C1 means that the power supply to the individual parking spaces is provided via a ribbon cable. If a resident acquires an electric vehicle, they can have the charging station installed by ewz within a short period of time at an agreed fixed price. The state-of-the-art charging stations are also suitable for bidirectional charging.
Dynamic load management
Dynamic load management regulates the available charging power with the aim of using as much of the carbon-neutral solar power as possible on site while avoiding peak loads at the same time. To this end, it continuously measures how much solar power is used in households, as supplying them with electricity is the first priority. The remaining power is available to the charging stations as a second priority. If the solar power is insufficient to cover the entire demand, electricity is drawn from the grid. If, on the other hand, the PV system produces more electricity than households and electromobility jointly consume at the same time, this electricity is fed into the grid. ewz assumes that the self-consumption share will be around 66 per cent.
Consumption-based billing
In order to make the most economical use of the solar power, the owner parties have also joined forces to form a self-consumption community based on the ‘distribution network operators’ model. This means that each party remains an ewz customer and selects its own electricity product for the purchase of grid electricity. The consumption of each household is measured at 15-minute intervals using smart meters and the consumption-based amount is shown on the bill by ewz as ‘ewz.solarsplit’. ewz also bills the electricity used to charge electric vehicles individually.
High efficiency thanks to integrated energy solution
Thanks to the contracting model for the PV system, owners do not have to make major investments to benefit from affordable solar power in the future, with a fixed rate that is lower than that for grid electricity. ewz will also be responsible for the reliable operation and maintenance of the PV system for 25 years. It is in our mutual interest to continuously optimise the system and increase its efficiency on the basis of monitoring consumption data. After the contract expires, the system will be transferred to the freehold apartment owners and will be able to produce solar power for another five to ten years.
However, the solar power plant and charging stations for electromobility are not the only services that ewz has provided for the four Minergie residential buildings in the Guggach district. The residential complex has been connected to the ewz district heating network since residents moved in. Thanks to ewz’s integrated energy solution, the site has gradually developed into an environmental showcase project.
