What is a photovoltaic system?
A photovoltaic system (PV system) is a technical system that converts sunlight into electrical energy and makes it usable. It essentially consists of five components:
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Created on 21.11.2023
Photovoltaic systems: sustainable living with your own solar power system
Photovoltaic systems are an excellent way to produce sustainable, fossil-free solar power yourself and to become more independent from electricity providers and the volatility of energy market prices. But what does a photovoltaic system involve? What types are there? And are they worth the investment? You’ll find the answers here.
Components of a photovoltaic system
Solar modules
These collect sunlight and convert it into direct current. They are made of semiconductor materials such as silicon. There are three types of solar module:
- Monocrystalline modules consist of just one crystal and are particularly suitable for smaller roof areas (efficiency rate : approx. 20 percent)
- Polycrystalline modules consist of several crystals and are particularly suitable for larger areas (efficiency rate : approx. 14 percent)
- Thin-film modules are only 0.001 mm (1 micrometre) thick (efficiency rate : approx. 6 to 10 percent)
Inverter
This converts the direct current into alternating current, which is fed into the home grid and, where applicable, into the public grid.
Controller
This monitors the smooth running of electricity generation. In more modern systems, this function is integrated into the inverter.
Meter
This measures how much solar power is fed into the grid and how much electricity is drawn from the grid. As a rule, your own consumption of solar power is also measured.
Battery storage
Energy storage is increasingly becoming part of the system. Storage enables you to significantly increase the proportion of self-generated electricity in your total electricity consumption.
Rooftop or in-roof system – which is better?
In addition to different types of solar modules, there are also different ways in which they are installed. Two basic types are available: rooftop and in-roof systems. For rooftop systems, the modules are mounted on the existing roof. For in-roof systems, the modules themselves form the roof cover and thus also take on a protective role. Solar tiles also belong to this category. However, solar modules do not necessarily have to be on the roof, but can also be attached to the facade.
When is each type of installation recommended?
There is no definitive answer to this question. The factors that need to be taken into account in individual cases are too diverse, such as location, orientation, aesthetics, monument protection, financial options, etc. The following provides a general overview along with the advantages and disadvantages of the two variants:
| Building method | Suitable for... | Advantages | Disadvantages |
|---|---|---|---|
| Building method Rooftop system |
Suitable for... ...practically all roofs (pitched, flat, etc.), especially on existing buildings |
Advantages Relatively easy installation Relatively inexpensive (from approx. CHF 150/m²) |
Disadvantages Aesthetics |
| Building method In-roof system (including solar tiles) |
Suitable for... ...for pitched roofs that also have a sufficiently large area in a suitable orientation to the Sun ...especially for new buildings, roof renovations and listed buildings |
Advantages Individual design, especially with solar tiles, aesthetics Costs for conventional roof coverings are completely or partially eliminated Highly resistant (especially solar tiles) |
Disadvantages Relatively complex and expensive (from around CHF 300/m², solar tiles from around CHF 225/m²) Not possible for certain roof coverings (e.g. sheet metal or bitumen) Relatively low power (solar tiles) |
How much does a photovoltaic system cost?
The price of a photovoltaic system depends heavily on the type of system, the type of module chosen, the devices chosen (inverter, meter, storage if required) and the manufacturer. As everywhere else, products from Asia in this sector are generally somewhat cheaper but overall less sustainable than European brands.
As a whole, costs have fallen sharply in recent years and decades. Twenty years ago, it cost around two francs to produce 1 kilowatt hour (kWh) of solar power. Today, it costs around 20 centimes. Strong market growth and rapid technological development have contributed to this price trend. The efficiency rate of solar modules is increasing, and production costs are falling due to mass production. The bottom line is that this means lower costs for the desired output.
The following is a cost example for a PV system on an average single-family home with four residents:
Solar module area: 29 m²
Nominal power : 5 kWp
Cost: CHF 19,000
Subsidies from the federal government, cantons and municipalities
However, the amount mentioned above would be reduced considerably thanks to public funding. The federal government supports private solar power production with its one-off remuneration. This consists of a base amount and a performance amount per installed kWp. The total one-off remuneration is up to 30 percent of the investment costs for a reference system.
Tip
You can use energiefranken.ch to find out quickly and easily whether you can apply for funding in your municipality and which funding sources apply.
Is it worth investing in photovoltaics?
The answer to this question is a definitive yes. According to the experts, if you take the subsidies into account, a photovoltaic system can pay for itself within around 10 to 15 years, thanks to the saved costs for grid electricity. This is well before the end of their lifespan, which is at least 30 years. A kilowatt hour of solar power produced on your own roof now costs less than a kilowatt hour from the public power grid. “Grid parity” has therefore already been achieved, and production costs for solar power will continue to fall thanks to technical progress.
Also, when it comes to the overall CO2 balance, solar power is making steady progress. A modern solar power system in Switzerland has already generated more (emission-free) electricity in three years than was needed for its production.
Get advice from an expert
The market for solar modules and PV systems is now very large and confusing. Solar technology is also progressing rapidly, so new products are constantly coming onto the market. It is difficult for a non-expert to make the right choice. The best approach is to consult a professional who can help you find the best solution for you and your home.
Questions and answers
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Yes, technically speaking, solar modules can be installed on all roofs, including flat roofs. However, installation is a little more complex because the modules also have to be “supported” with frames – i.e. they have to be placed at the optimal angle to capture the sunlight. The critical factor is the location of your home or the duration and intensity of the sunlight.
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Yes, but only if the system (regardless of whether it is rooftop or in-roof) is installed on an existing building. In this case, the costs can be deducted from your income like other maintenance costs. In return, the subsidies received must be taxed as “other income”.
PV systems in new buildings are also tax-advantaged, but in a different way. The costs are counted as investment costs, which leads to a reduction in property gains tax when the property is sold. In this case, funding is not taxed as “other income” but simply reduces the eligible investment costs.
Furthermore, there is the income from the free market that is generated with a photovoltaic system.
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Yes. A classic rooftop system is recommended for old or existing buildings. If a roof renovation is necessary in any case, an in-roof system is also an option. For a heritage building, solar tiles are probably the best choice.
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Photovoltaic systems convert solar energy into electrical energy, whereas solar thermal systems (often colloquially called solar systems) convert solar energy into heat for hot water and heating. However, both are solar systems in the true sense – i.e. systems that convert sunlight carbon-neutrally into another form of energy.
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Whether one or the other is better for your purposes depends on your needs and goals.
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Usually, yes. Storage enables the share of self-generated electricity in your total electricity consumption to be significantly increased.
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