Once the fundamental question of 'storage: yes or no' has been clarified, the specific ones follow: How large should the storage be, which cost factors play a role, and when does it pay off? This page goes into depth – from sizing to costs to economic viability. You will find the basic decision-making aid on the PV system with storage page.
Key points at a glance
The key points of this section can be summarised compactly:
- The appropriate storage size depends on the consumption profile, not on the maximum roof capacity.
- The costs depend on capacity, output, technology and additional features.
- Economic viability depends heavily on consumption, electricity prices, tariffs and feed-in remuneration.
- Emergency power or backup power is not automatically included and must be explicitly planned.
- The specific figures are only provided by an individual quote.
Therefore, economic viability depends not only on storage costs, but also on the consumption profile, tariff model, and desired additional features.
- As of 13.07.2026
What does the battery storage do in a photovoltaic system?
The storage unit absorbs excess solar power that is not consumed directly during the day and releases it later – usually in the evening. This increases self-consumption and reduces grid import. It is a component of the overall planning and works best in conjunction with an energy management system that coordinates generation and consumption. In apartment buildings and on sites, a association for self-consumption (ZEV) can further increase communal self-consumption.
How is the battery storage size calculated?
The sensible capacity is determined by daily consumption, the proportion of evening and night consumption, and the system size. A battery storage unit that is larger than the usual evening demand will rarely be fully used and therefore offers less value. A storage unit that is too small does not fully exploit the potential:
| Consumption profile | Sizing the battery storage |
|---|---|
| Low consumption, much during the day | Small storage or none |
| Average consumption, evening load | Storage suitable for the evening load |
| High consumption, heat pump/electric car | Larger battery storage, check energy management |
This table is only for rough orientation. The appropriate size is derived from your actual consumption data and specialist planning.
Which cost factors influence the battery storage?
The most important influencing factors are compared in the following overview:
| Cost factor | Influence |
|---|---|
| Usable capacity (kWh) | Key factor for the price |
| Output (kW) | How fast it is charged and discharged |
| Technology and quality | Lifespan, cycles, warranty |
| Backup power / emergency power function | Additional technology and costs |
| Integration and installation | Effort for integration and electrical work |
| Energy management system | Control of consumers |
For a reliable assessment, these points should always be considered together with location, consumption and specific quote.
How do self-consumption, electricity prices and feed-in remuneration affect cost-effectiveness?
Whether a battery storage system is cost-effective depends on several factors: consumption profile, location, electricity prices, tariffs, price trends for storage systems, and roof potential. Simplified, the higher the grid electricity purchase price and the lower the feed-in remuneration, the more attractive it becomes to use electricity yourself rather than feeding it into the grid. You can read how the remuneration works on the page Feed-in remuneration Switzerland.
Because so many factors interact, the economic efficiency cannot be quantified in general terms. It reacts sensitively to your individual consumption behaviour – therefore, a project-specific assessment is necessary.
How does storage with a heat pump work?
A heat pump noticeably increases electricity consumption and shifts it partly to the colder, sunnier months. A battery storage system can provide electricity generated during the day for evening use. The extent to which this is economically sensible depends on the heating system, the building and the consumption profile.
How does a battery storage system work with an electric car?
An electric car is a large but flexible consumer. If it charges during the day with solar power, direct self-consumption is often cheaper than routing through storage. If it charges in the evening, a battery storage system can help. An energy management system controls which consumer is served when.
What is the difference between emergency power and backup power?
A common misconception: a battery storage system does not automatically provide electricity during a power outage. A backup power or emergency power function requires additional technology and must be explicitly planned and offered. Standard battery storage solutions and backup power solutions differ in scope and price:
| Standard storage solution | Backup power / emergency power solution |
|---|---|
| Increases self-consumption | Increases self-consumption |
| No automatic operation during a grid outage | Supplies defined consumers during a grid outage |
| Less additional technology | Additional technology and costs |
| Does not need to be commissioned separately | Must be explicitly planned and commissioned |
Anyone expecting power supply during a grid outage should explicitly request this feature in the quote.
solar-guide.ch recommends: Have the storage specifications clearly stated in the quote – usable capacity, power output, and whether a backup power or emergency power function is included. Emergency power is not automatically included. If you value this, you must explicitly plan for it and request it in the quote.
Which storage specifications must be included in the quote?
In the quote, the battery storage specifications should be specific enough to keep the technology, benefits and additional costs comprehensible:
- usable capacity in kWh and power in kW
- Technology, expected lifespan and warranty
- whether backup power/emergency power is included
- Integration into an energy management system
- Installation and integration effort
- Price, shown separately
This makes it easier to see quickly whether a quote is complete, comparable and plausibly structured.
Conclusion
For a photovoltaic system with battery storage, compatibility is key: the right capacity, clear information on technology and functions, and a realistic assessment of economic viability. Because many factors interact, individual quotes are essential.
Storage solutions vary greatly in terms of power, capacity, backup capability, and price. Via solar-guide.ch, you can compare up to three individual quotes from suitable specialist installers in your region for free and without obligation.
Request quotes free of charge and without obligation
Frequently asked questions and answers
What does a photovoltaic system with battery storage cost?
This depends on system size, storage capacity, technology, and additional features such as backup power. A reliable price only emerges with specific building data and individual quotes.
How large must the battery storage be?
The appropriate capacity depends on the consumption profile, particularly evening and night-time consumption. An oversized battery storage system is rarely fully utilised.
Is backup power included automatically?
No. A backup power or emergency power function requires additional technology and must be explicitly planned and offered.
Should the battery storage be installed at the same time?
This depends on budget, consumption and planning. Direct installation saves a second mounting visit; retrofitting is also possible with appropriate preparation.
What information should be included in a battery storage quote?
Usable capacity and output, technology, lifespan and warranty, whether backup power is included, integration into an energy management system and the separately stated price.
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