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Solar system: costs and yields in comparison
Solar system: costs and yields in comparison

Video: Solar system: costs and yields in comparison

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Video: ☀️Which is Better-- Solar Energy or Wind Energy? 2023, February

Solar systems make a valuable contribution to climate protection and many want to benefit from environmentally friendly electricity. However, the feed-in tariff for new systems will expire completely by the end of 2020 - and therefore homeowners in particular are wondering whether it is still worth investing in a solar system. To determine the profitability of photovoltaics, it is important to calculate the costs and yields as realistic as possible in advance. We have put together the most important information for you here.

Table of contents Table of contents Is a solar system worthwhile? Comparison of costs and income

  • How a solar system works
  • Feed in electricity from the solar system or use it yourself?
  • Photovoltaics: costs and returns
  • How useful is electricity storage?
  • Realize feed-in tariffs
  • Financing and funding opportunities for solar systems
  • Realize tax savings
  • Insure solar system

Table of contents Table of contents Is a solar system worthwhile? Comparison of costs and income

  • How a solar system works
  • Feed in electricity from the solar system or use it yourself?
  • Photovoltaics: costs and returns
  • How useful is electricity storage?
  • Realize feed-in tariffs
  • Financing and funding opportunities for solar systems
  • Realize tax savings
  • Insure solar system

Is it profitable to buy a solar system? What does it cost to install the system and what are the expected returns? Many homeowners who are interested in photovoltaics ask themselves these central questions. The prices for solar systems are cheaper than ever - but the feed-in tariff is also lower than ever and will expire completely for new systems in 2021. So it alone is no longer a reason to buy a solar system. Independence from the supplier, the use of renewable energies and thus the support of climate protection in decision-making play a greater role. The focus is on new possibilities for storing the generated electricity, because a solar system is worthwhile especially if you can use as much of your own electricity as possible. Last but not least, there is also the question of how the acquisition costs for a solar system can be financed and whether there is still government funding.

How a solar system works

There are basically two ways to use the power of the sun for your home: photovoltaic and solar thermal. In a solar system, the solar modules - consisting of interconnected solar cells - convert sunlight into direct current. So-called inverters turn it into household AC. You can use it for your own use or feed it into the public power grid. A solar thermal system, on the other hand, converts sunlight into heat for water and heating with the help of collectors.

Photovoltaikanlage auf dem Dach installieren
Photovoltaikanlage auf dem Dach installieren

Photovoltaics is one of the renewable energies and is a comparatively simple and inexpensive method of generating electricity.

/ Elena Elisseeva

Feed in electricity from the solar system or use it yourself?

In the past, owners of solar systems have largely fed the collected electricity into the public grid and received a feed-in tariff from the state. This refinanced the purchase of photovoltaics and even made profits. However, this model is no longer worthwhile due to the continuously falling state remuneration for private operators - it will expire at the end of 2020 anyway.

It is therefore more lucrative for homeowners to consume the electricity they generate themselves in the home, thereby making them less dependent on the public power grid and rising electricity prices. You use the savings to refinance the costs of the solar system and lower your monthly electricity bill right from the start. You also contribute to climate protection with environmentally conscious, sustainable and decentralized electricity production.

Photovoltaics: costs and returns

In principle, the purchase of a solar system should be carefully planned, because it has to fit the building in order to generate optimal yields. You should therefore always have a reliable calculation of the costs for a solar system and the expected yield done by a specialist who has previously been able to get a precise picture of your roof area on which the solar system is to be installed. However, a rough estimate of the return based on guide values ​​is also possible with just a few key data.

System performance Electricity production

in the year

Space requirements Approximate cost

including assembly

3 kWp 2830 kWh 16.5 sqm from 7, 000 euros
4.5 kWp 4250 kWh 24.8 sqm from 10, 000 euros
6 kWp 5660 kWh about 33 sqm from. 12, 400 euros
7.5 kWp 7080 kWh approx.41.2 sqm from 13, 900 euros
9 kWp 8500 kWh approx.49.5 sqm from 16, 400 euros

Source: E.ON

The price per kilowatt peak is a comparative figure for photovoltaic systems and, including the inverter, installation and commissioning, is around 2300 euros net (as of 2020). About four to five photovoltaic modules correspond to a kilowatt peak and occupy a roof area of ​​about eight to ten square meters. The price of a solar system for a four-person household (electricity requirement about 4, 500 kWh per year) is around 10, 000 to 12, 000 euros. There are also annual operating costs of around 200 euros. This essentially concerns meter rental, insurance and cleaning costs. The latter can be saved if you climb the roof yourself at least once a year and clean the modules of dust and deposits.

How economical a solar system is depends on three different factors:

  • acquisition cost
  • geographical location
  • Alignment and inclination of the roof area
Kosten einer Solaranlage kalkulieren
Kosten einer Solaranlage kalkulieren

The cost of a solar system for your house depends on several factors, such as the power required and the existing roof area.

Photo: iStock / Vicente García Marín de

How useful is electricity storage?

On average, operators of (old) solar systems use only a quarter of the electricity generated. After all, a photovoltaic system generates the most electricity at lunchtime - however, the least energy is usually used during this time. In the evening, at night or in the dark winter months, however, the electricity yield of the solar system drops. A power storage can store the unused solar power from sunny times, but powerful and long-lasting power storage with lithium-ion technology is still quite expensive: depending on the system and technology, they cost between 6, 700 and 8, 500 euros.

Tip: Electricity storage is especially useful for owners of an electric car. If this is charged at night with cheap storage electricity from our own production, this lowers our own electricity costs and the purchase of the storage pays for itself relatively quickly.

Physical electricity storage

With a locally operated battery storage, you gain up to 70 percent independence from the regional electricity provider. But: The cost of self-produced electricity must not exceed the cost of purchasing electricity. What does that mean? A kilowatt hour from a solar system costs an average of 10 cents, but every kilowatt hour from the power grid costs between 24 and 30 cents. If you want to save with an electricity storage device, you can spend between 14 and a maximum of 20 cents per kilowatt hour to store the electricity. A good way to ensure this is by financing the electricity storage. At first glance, storage costs of 20 cents seem like a zero-sum game. However, you have to take into account that these costs only apply to the stored share of electricity - not to those that are used directly.

Virtual electricity storage

With this model, you feed the surplus electricity that you produce into the grid, thereby filling a virtual electricity account. In a way, you build up a credit balance, similar to a savings book. On gloomy days, at night or in the winter months, you can simply call up this electricity credit again and use it yourself at affordable prices. So nothing is lost with the E.ON Solar Cloud and you ultimately consume 100 percent of the electricity you produce yourself. This variant can also be used as a supplement to the local electricity storage.

Realize feed-in tariffs

You will receive a guaranteed amount for feeding the electricity you generate into the public grid, for which the energy suppliers will have to purchase solar power every kilowatt hour. However, the amendment to the Renewable Energy Sources Act (EEG) provides for the continuously falling remuneration of one percent per month. In addition, only solar systems with a nominal output of up to 100 kilowatt peak, which will be purchased by the end of 2020, will receive a feed-in tariff at all.

New solar systems that exceed this output receive a one-time market bonus as funding and must also hire a direct marketer for the electricity they feed into the grid. Nevertheless, installing the solar system pays off because the modules have become cheaper. You also benefit from the tax advantages. You can find out what effects the current remuneration rates have on the economic efficiency of a new solar system with the help of photovoltaic computers.

Financing and funding opportunities for solar systems

You can also implement the installation of the solar system without equity by financing the purchase. With the E.ON Sunrate, for example, you save the initial investment and become a photovoltaic owner with monthly installments.

State subsidies for the purchase of a solar system

The KfW funding program for electricity storage expired in 2018. But with the KfW 270 credit "Renewable Energies - Standard", photovoltaic systems on roofs, facades or open spaces as well as battery storage are still subsidized by the state. This means that up to 100 percent of your investment costs can be financed and repaid with an effective annual interest rate of 1.03 percent.

In addition, KfW loan 153 "Build Energy Efficiently" supports builders of an efficiency house according to the KfW standard, who are often equipped with a solar system.

Individual federal states also subsidize the purchase of a solar system or electricity storage. Here is an overview:

state Funding program content
Bavaria PV storage program Grant of 500 to 3, 200 euros for

Battery storage

Rhineland-Palatinate Solar storage program 100 euros per kWh (up to a maximum of 1, 000 euros)

usable storage capacity of a local

Electricity storage in connection with

a new photovoltaic system

Saxony-Anhalt Promotion of electricity storage

for photovoltaic roof systems

Up to 30 percent of the acquisition costs for

a local electricity storage (maximum 5, 000 euros)

in connection with a new solar system

Thuringia Solar Invest Up to 900 euros per kWp for new ones

Photovoltaic systems with battery storage, 300 euros per kWh for a battery storage

Realize tax savings

If you generate solar power on the roof of your home and feed it into the public grid, you become an entrepreneur. Therefore, private home owners can also apply for the investment deduction amount from the tax office. 20 percent of the purchase price of the photovoltaic system can be billed to the tax authorities in advance as a special depreciation. This is already possible for the year in which the investment intent is fixed (BFH, file number XR 42/11). You must have bought the solar system at the latest three years later. This early tax relief makes financing easier.

The normal tax depreciation of the solar system takes place from the year of commissioning over a period of 20 years, each with 5 percent of the acquisition costs. Like every entrepreneur, you have to tax the income from feeding electricity into the public grid. In return, you can deduct all expenses for the operation of your solar system from taxes. Since the tax treatment of solar systems is on the one hand quite complex, but on the other hand also offers interesting depreciation options, you should speak to your tax advisor about this at an early stage.


A photovoltaic system increases the value of your home. You can co-insure the system with your home insurance.

Photo: Fotalia / Reimax16

Insure solar system

A photovoltaic system increases the value of your home. You can co-insure the system with your home insurance. Some insurance companies also offer special insurance packages for solar systems. This covers natural risks such as fire, storm or hail, as well as damage due to incorrect operation, vandalism, theft, short circuit and marten bite. In these cases, the loss of income is also insured if the solar system can no longer generate electricity.

Eva Bolta Redaktion

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