Emergency power PV system: How to keep your home supplied with solar energy
A sudden power cut can paralyze more than you might think: heating, internet, lighting, fridge - nothing works anymore. Especially in times of rising energy prices and the threat of blackouts, many homeowners are asking themselves: Can I use my own PV system in the event of a power outage?
The good news: Yes, it is possible - with an emergency or backup power solution. With the right retrofit, you can expand your photovoltaic system so that it continues to produce solar power and reliably supply your home even in the event of a grid failure.
Find out in this article:
- How emergency power from the PV system works
- What technical requirements you need
- Which systems from Voltsmile and Victron Energy are particularly recommended
- What does a retrofit cost
What does emergency power from the PV system actually mean?
When talking about emergency power supply, terms such as backup power, UPS or emergency power socket quickly come to mind. But what is actually behind them? And what are the differences between the systems?
Basically, the aim of a PV system with an emergency power function is to continue to supply certain consumers or even the entire household with electricity in the event of a power failure - independently of the public power grid.
To do this, the solar power generated by your photovoltaic system is temporarily stored in a battery storage system. If the grid fails, a special inverter with emergency power function automatically disconnects your system from the public grid. Your home will then continue to be supplied with electricity via the storage system and the PV system.
| Begriff | Bedeutung | Anwendung im Haushalt |
|---|---|---|
| Notstrom | Versorgung einzelner, wichtiger Geräte über eine Notstromsteckdose | Kühlschrank, Router, Licht |
| Ersatzstrom | Stromversorgung des gesamten Haushalts durch automatische Umschaltung | Vollständige Autarkie bei Stromausfall |
| USV (unterbrechungsfreie Stromversorgung) | Sofortige Überbrückung ohne Unterbrechung, z. B. für IT-Systeme | Server, Alarmanlagen |
How does emergency power work with a PV system?
In the event of a power outage, the inverter automatically disconnects from the public grid - this is called grid disconnection. The system then switches to off-grid operation.
From now on, your photovoltaic system, together with the battery storage system, takes over the power supply to your home. While solar power continues to be produced during the day, the storage system supplies your home's most important consumers in the evening.
The heart of the system is an inverter with backup power capability. Devices such as the Victron Energy MultiPlus-II offer this function: they automatically detect grid failures, switch over in milliseconds and maintain the power supply.
Retrofitting an emergency power PV system
Many homeowners already have a PV system but have not yet integrated an emergency power function. The good news is that you can retrofit your existing PV system to make it capable of providing emergency power.
What is done during the retrofit?
When retrofitting a photovoltaic system, the following are usually installed
- an inverter with backup power capability,
- a suitable battery storage system,
- and an automatic transfer switch are installed.
These components ensure that your system automatically switches to emergency power operation in the event of a power failure.
Technical requirements
- Existing PV system with sufficient power (at least 5 kWp recommended)
- Inverter with emergency power or backup power function (e.g. Victron MultiPlus-II)
- Storage size suitable for the power requirements of your household (e.g. Voltsmile battery storage 10 kWh)
- Installation by a certified specialist company
What does it cost to retrofit emergency power?
The cost of retrofitting depends on the existing components, but is usually between 2,000 € and 6,000 €. The size of the storage system is particularly important here - larger systems cost more, but also offer longer self-sufficiency times.
When is retrofitting worthwhile?
Retrofitting makes particular sense if you:
- regularly expect power outages (rural areas, grid fluctuations),
- operate a heat pump, heating control or medical devices,
- or want to make your energy supply independent of the grid in the long term.
Recommended systems for retrofitting and backup power operation:
- Compact battery storage with black start function
- Victron Energy MultiPlus-II - intelligent inverter with automatic grid switching
Emergency power supply: What is technically necessary?
To remain truly independent in the event of a grid failure, an emergency power PV system needs a few additional components. These ensure that the power supply is switched over automatically and safely.
The most important technical requirements:
| Komponente | Funktion |
|---|---|
| Wechselrichter mit Notstromfunktion | Erkennt Stromausfälle und schaltet automatisch auf Inselbetrieb |
| Batteriespeicher | Speichert Solarstrom für die Nutzung während des Stromausfalls |
| Umschalteinrichtung (automatisch) | Trennt das Hausnetz sicher vom öffentlichen Netz |
| Schwarzstartfähiger Speicher | Startet das System selbstständig nach einem vollständigen Netzausfall |
| Notstromsteckdose oder Ersatzstromkreis | Versorgt definierte Verbraucher mit Strom im Notfall |
Diese Komponenten sorgen gemeinsam dafür, dass deine Photovoltaikanlage bei Stromausfall nicht einfach abschaltet, sondern dein Zuhause weiter mit Energie versorgt. Wenn du Interesse an einer PV-Anlage hast, komm auf uns zu – wir beraten dich umfassend!
Notstrom aus der PV-Anlage: Beispiele für Haushalte
Wie viel Notstrom kann eine PV-Anlage mit Speicher tatsächlich liefern? Das hängt von der Kapazität des Batteriespeichers und vom Stromverbrauch im Haushalt ab.Ein typischer 10 kWh-Speicher reicht in der Regel aus, um die wichtigsten Geräte für mehrere Stunden oder sogar Tage zu versorgen – abhängig von deinem Energiebedarf.
Beispielrechnung: Wie lange reicht ein 10 kWh-Speicher bei Stromausfall?
| Verbraucher | Leistung (W) ca. | Betriebszeit pro Tag (h) | Täglicher Verbrauch (Wh) | Versorgungsdauer bei 10 kWh Speicher (Einzeln) |
|---|---|---|---|---|
| WLAN-Router | 10 | 24 (Dauerbetrieb) | 240 | ca. 41 Tage |
| Kühlschrank (modern) | 100 (wenn aktiv) | 4 (effektive Kühlzeit)* | 400 | ca. 25 Tage |
| Heizungspumpe (Hocheffizienz) | 25 | 24 (Dauerbetrieb) | 600 | ca. 16 Tage |
| Beleuchtung & Laden (Handy/Laptop) | 100 | 4 | 400 | ca. 25 Tage |
| Gesamtverbrauch | — | — | ca. 1.640 Wh (1,6 kWh) | ca. 5-6 Tage |
*Hinweis zum Kühlschrank: Das Gerät ist 24 Stunden eingesteckt, der Motor (Kompressor) läuft aber dank Isolierung nur in Intervallen (Takten), insgesamt ca. 4-5 Stunden pro Tag.
Why an emergency power PV system is worthwhile
The emergency power function makes your PV system a reliable backup for everyday life and in the event of a power outage. With the right combination of inverter with backup power function, battery storage and automatic switchover, you are
- Independent of the public grid
- Can continue to supply the most important consumers
- Also benefit from self-sufficient use of solar power, even during longer power outages.
With our devices, your existing PV system can easily be retrofitted with emergency power capability. This ensures that your household remains supplied with power even during blackouts or power cuts - and that you can make optimum use of your PV system in the event of a power cut.
Do you still have questions about emergency power PV systems?
Does emergency power also work without storage?
No, a battery storage system is essential. Without a storage system, the inverter is automatically switched off in the event of a power failure to prevent it being fed back into the public grid. This means that even if your PV system is producing solar power, it cannot be used. A storage system ensures that the electricity generated is stored and supplied to the most important consumers in the home via the emergency power supply when required.
Can I have my PV system retrofitted at any time?
Yes, retrofitting is possible in most cases. It is important that the existing PV system, the inverter and the cabling for an emergency power function are compatible. Modern inverters, e.g. from Victron Energy, enable uncomplicated integration. A certified specialist company will check the requirements, dimension the appropriate battery storage system and install the necessary automatic switchover device so that your home is reliably supplied in the event of a power outage.
Which devices can I supply in emergency power mode?
With a correctly dimensioned emergency power PV system, all important consumers can be secured: refrigerator, freezer, lighting, router, heating pumps and heating controls. The exact selection depends on the storage capacity and the power of the inverter. You need a backup power system with a sufficiently large battery for the entire household.
How quickly does the system switch?
Modern inverters with an emergency power function automatically detect a power failure and switch to stand-alone operation within seconds. This means that your household is immediately supplied with emergency power from the PV system and the storage system. With UPS systems, the switchover can even take place without interruption so that sensitive devices such as computers, routers or medical devices do not experience a power interruption. Automatic switching ensures that you can use solar power efficiently even during power outages.
What happens if the storage tank is empty and the power cut continues?
This is the biggest advantage of an emergency power PV system: as soon as the sun shines, your inverter can activate the system and recharge the storage system. Your home is supplied directly with solar power during the day. This is often not the case with simple emergency power solutions: once the storage system is empty, it remains so until the public grid is available again. The ability to recharge is therefore a decisive criterion for real autonomy.
Can I also operate my heat pump or my electric car with emergency power?
Yes, this is technically possible, but requires a powerful backup power system. Heat pumps and Wallboxes are 3-phase large consumers with high starting currents. A simple emergency power socket is not sufficient here. You need a powerful, 3-phase inverter and a sufficiently dimensioned battery storage system. The system must be planned for these high loads from the outset in order to ensure stable operation in the event of a power failure.
Is an emergency power PV system subject to registration?
Yes, every emergency power PV system must be registered both with the responsible grid operator and in the Federal Network Agency's market master data register. The grid operator must be informed about the "islanding capability" of your system in order to guarantee the security of the public grid. Installation and registration must be carried out by a certified specialist company that ensures compliance with all technical connection regulations and takes care of the formalities for you.