Installing your own solar system is an attractive step for many people: you do something good for the environment and even have a financial advantage. But how long does the photovoltaic system actually pay off?
payback period
If you are thinking about purchasing your own solar system, the question of the payback period is one of the most important ones you should ask yourself. This is the period of time that is required until the previously incurred costs or resources used have been recouped. When installing a photovoltaic system, costs initially arise – both material and ecological. The so-called energetic amortization refers to the period until more energy is produced through the operation of the system than was used to produce it, which, according to Photovoltaek.org, takes around five years in Germany, depending on the module and location. Although you can enjoy the feeling of doing something good for the environment right from day one, the actual ecological benefits only begin after this time has passed.
However, you have to wait a lot longer for the solar system to pay for itself financially, usually around ten years. However, you should not forget that the system will serve you for between 25 and 30 years. As Echtsolar explains, the payback period is much better as a parameter for evaluating photovoltaic systems than the return, as it is not possible to make precise forecasts for the ultimate return.
The unpredictable influence of global radiation
Calculating the payback period of a solar system is only possible approximately, as an exact prediction cannot be made for many of the relevant factors. The biggest and crucial unknown here is global radiation, i.e. the solar energy that affects a surface, in this case the solar panels of the system under consideration. The connection is simple: the more intense the global radiation, the greater the amount generated by the solar system. In short, the full solar energy is not used when operating the system, as there are always losses due to cloud formation, air pollution or reflection.
The second important factor that can reduce the yield of the system is so-called shading. However, the system owner can influence this to a much greater extent, for example by creating a shading analysis in advance of installing the system.
When does the solar system become profitable?
If you now want to calculate the payback period of your own solar system, there is a simple formula that EFahrer.com has presented. First, the investment costs must be established, i.e. all costs incurred when installing the system on the roof. These consist of the solar modules themselves, the costs for the metal frame, tracking system, analysis and assembly costs as well as the fees for acceptance and the meter plus any interest if a loan was taken out to purchase the system. On top of this, ongoing costs are added, such as the electricity consumption of the photovoltaic system as well as maintenance, cleaning and insurance.
These costs are now compared with the returns from the system. Particularly worth mentioning here are the feed-in tariffs, the payment of which is guaranteed by the EEG Act. The amount of this depends on the electricity yield, which largely depends on global radiation. Depending on how far north or south you live in the country, this varies by 100 to 200 kilowatt hours per square meter per year. Apart from that, factors such as the quality of the solar modules, the location, the installation of a tracking system as well as any subsidies and depreciation also determine the payback period.
If you now divide the total acquisition costs by the total income, this gives you the approximate payback period for the photovoltaic system. On average, this is between ten and 15 years, depending on the individual requirements.
Thomas Weschle / editorial team finanzen.net