In Küsnacht on Lake Zurich, we have realised a photovoltaics system with 24.71 kWp on a single-family home and combined it with a salt battery storage of around 18 kWh. The house thus covers a large part of its electricity demand itself and remains partially supplied during a power cut thanks to the emergency power function. In operation since May 2023.
Key points in brief
- 24.71 kWp on the south-facing roof – 61 modules with 405 watt-peak each.
- Battery made of salt instead of lithium: non-combustible and without critical raw materials.
- Emergency power-capable and partially off-grid capable – in the event of a power cut, important consumers continue to run.
- Two inverters combined so that yield and battery interact optimally.
- Grid operator: Werke am Zürichsee. Commissioning: May 2023.
What was the initial situation?
The ownership in Küsnacht wanted to combine two things that clash a bit at first glance: the highest possible share of own solar electricity and a battery where neither fire protection nor the origin of raw materials are an issue. The roof – facing south, with a moderate pitch – offered a good foundation for this.
Especially on Lake Zurich, the question of safety in the cellar is justified: a battery storage is often in the plant room next to the heating and laundry room. Whoever does not want a lithium battery there has a serious alternative with a salt battery – that was the starting point for the planning.
Which solution did we implement?
61 modules with a total of 24.71 kWp were placed on the south-facing roof. For the conversion, we use two inverters: a grid-tied Huawei inverter for the continuous feed-in and a Victron charge controller that serves the salt battery. This division sounds more complex than it is – it ensures that the solar yield and battery are regulated cleanly separately and the emergency power function works reliably.
| Component | Execution |
|---|---|
| Service | 24.71 kWp (DC) / 21 kVA (AC) |
| Modules | 61 × Tommatech, 405 Wp each |
| Inverter | Huawei SUN2000-12KTL-M2 (grid-tied) + Victron SmartSolar RS450 |
| Speicher | salidomo 18 (sodium-nickel chloride salt battery), around 18 kWh, AC- and DC-coupled |
| Distinctive feature | Emergency power function, partially off-grid capable |
| Roof | Pitched roof, orientation south, pitch around 22–27° |
| Grid operator | Utilities on Lake Zurich |
| Commissioning | May 2023 |
Information according to the measurement and test report of the system. The yield values of a system depend on orientation, shading, and usage.
Why a salt battery storage?
To be honest: for most single-family homes, a lithium battery is still the more compact and cheaper choice. The salt battery shows its strengths where other criteria are in the foreground – and that is exactly what was the case here.
A salidomo 18 is installed – a home battery based on sodium-nickel chloride cells, as they are manufactured in Ticino; the cells work internally at around 250 °C and are thermally insulated from the outside. The advantages that were decisive in this project: the cells are non-combustible, they do not require cobalt and lithium, and they can withstand many charging cycles without aging significantly. On the other hand, there is a larger space requirement and higher costs per kilowatt-hour. Whoever knows this trade-off and weights the safety and sustainability arguments higher, makes a conscious decision with a salt battery. The fundamental classification for this is provided by our article Battery storage: Technology and chemistry.
How did the implementation go?
From planning to commissioning, the same path always applies with us – the technical planning, the registration with the grid operator, the installation and finally the acceptance with the measurement and test report. With Werke am Zürichsee, the registration process is straightforward; what is crucial is that the documents are complete from the beginning.
The actual installation on the south-facing roof was done quickly thanks to good accessibility. The integration of the battery including the emergency power switchover required a little more care: in the event of a grid failure, the system must disconnect cleanly from the grid and continue to supply the defined consumers. We always test this switchover for real during the acceptance – a short but important moment that shows whether everything works as planned in an emergency.
What does the system bring in operation?
The system produces a large part of the electricity that the house needs over the year itself – directly during the day, from the battery in the evening. A reliable guideline value for the region is around 950 to 1,100 kWh per kWp and year; the exact value depends on orientation, weather, and usage. How much of it stays in the house and how much goes into the grid is decided by the consumption profile – the battery shifts this share noticeably in favour of self-consumption.
The additional benefit, which is difficult to express in a number: in the event of a power cut, the house is not completely in the dark. How far the calculation works out in individual cases, whether with or without a battery, is classified by the article Self-consumption or feed-in?.
Salt batteries are larger and heavier than a comparable lithium battery – many underestimate this during planning. We therefore clarify the installation location and the transport route into the plant room early on, not just on the day of installation. In this project, this paid off: in the end, the battery stood exactly where it belonged, without improvisation on site.
Frequently asked questions
Is a salt battery storage safe in a residential building?
Yes. Salt batteries are non-combustible and do not emit critical gases. This is one of the main reasons why they cut a fine figure in the plant room of a single-family home – especially where the battery is next to the heating.
How does a salt battery differ from a lithium battery?
The salt battery is non-combustible and does not require cobalt and lithium, but it needs more space and costs more per kilowatt-hour. What fits for which household depends on priorities – the classification is provided by the article Battery storage in winter.
What happens during a power cut?
The system disconnects from the grid and continues to supply defined consumers from the battery. It is partially off-grid capable – the exact coverage is determined during planning.
Which salt battery system is installed in Küsnacht – and who looks after it today?
A salidomo 18 with around 18 kWh, AC- and DC-coupled, with emergency power output. The original system provider innovenergy filed for insolvency in 2024; the cells come from FZSoNick in Stabio TI and continue to be produced there. The first point of contact for operation and service remains ecoEn, as with all our systems – we know the system and its integration. Since the insolvency, we no longer offer the salidomo; for new systems we recommend LFP batteries from established manufacturers – the classification is in the article Saltwater battery.
Can I realise a similar system at my place?
In most cases, yes. The decisive factors are the roof, consumption, and your priorities when it comes to battery technology. It is best if we clarify this in an initial consultation without obligation – with a view of your roof and your electricity consumption.
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Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: Swissolar, Swiss Battery Monitor 2026 (cell production in Ticino); salidomo manufacturer data sheet; measurement and test report of the system (ecoEn), information from Werke am Zürichsee.
Last updated: 9 July 2026 · Author: ecoEn editorial team
