Solar power for the electric car - photovoltaic system for tenants and homeowners

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Photovoltaic system contribution image

Is photovoltaics a great advantage for electromobility or is the home photovoltaic system more appearance than reality? 

In this article, you will find out when it pays to have your own PV system, who is allowed to install their own PV system, what you should look out for and what photovoltaic subsidies are available.

Table of contents

Switching to electromobility has become increasingly attractive, particularly in the wake of price increases for conventional fuels. The question of whether an e-car is still financially worthwhile even after the rise in electricity prices, we have already been able to answer with a "yes". However, one important aspect that is often given too little attention is that you cannot generate your own gasoline, but you can generate your own electricity! There are therefore some innovative approaches, such as using your electric car to store the electricity you generate yourself. With so-called bidirectional charging the electricity can be reused to supply the household electricity when needed. But it doesn't always have to be a highly complex energy solution. What if you just want to install a few solar panels on your home to support your own energy consumption? The best way to do this is with the integrated wallboxto charge your electric car with the electricity you generate yourself? That's exactly what this article is about.

Solar system: What are the advantages and disadvantages?

Solar system advantages

  • Reduce your own electricity costs
  • Protection against potentially rising electricity prices
  • Refuel your e-car free of charge
  • Amortization of the solar system through reduced electricity demand after an average of 8-15 years
  • Higher degree of self-sufficiency in combination with energy storage
  • Clean, emission-free, noiseless
  • Integration into smart home concepts
  • Use of promotional offers

Solar system disadvantages

  • Electricity production depending on weather and season
  • Electricity production depending on the location and orientation of the house
  • One-off acquisition costs

When is photovoltaics worthwhile?

The first step is to analyze your own living situation. If you live in your own home, you probably have enough free space to operate your own photovoltaic system. But a photovoltaic system can often be worthwhile for tenants too. Supplied solar power is around four times more expensive than self-generated electricity. This is due to various taxes, levies and surcharges. The rule of thumb is that a photovoltaic system can cover around 30 % of your own energy consumption. With a connected solar power storage system and the corresponding comprehensive energy concept, up to 70 %. This is because the sun does not shine constantly all day and all year round and the weather is subject to change. Electricity generation is therefore particularly high at midday. You can therefore either store surplus electricity in a solar power storage system or feed it back into the grid in return for the feed-in tariff. All you need is a feed-in meter or bidirectional meter and registration with the grid operator. This means you can even benefit from your photovoltaic system when you are not at home!

Inforgraphic: How does a photovoltaic system work?
Inforgraphic: How does a photovoltaic system work?

What requirements must be met for a solar installation?

Free areas, such as roofs, are the most important prerequisite for your own PV system. The optimum orientation of these areas is south, but 60 - 70 % is also possible with a north-facing orientation compared to a south-facing orientation. For flat roofs in particular, it is advisable to carry out a structural analysis before installing the system. This will ensure that the load-bearing capacity of the roof is sufficient for the PV system. In addition to roofs, balcony façades or certain house walls may also be suitable for a PV system. In any case, you should avoid shading from buildings or trees on the planned PV system. This also applies to potential future shading, e.g. from growing trees. If you are a tenant, it is worth talking to your landlord or the building community to set up an initiative and find like-minded people.

On-roof or in-roof photovoltaics?

The advantages of photovoltaics are obvious. However, whether a PV system on the roof meets your own aesthetic expectations is another matter. Fortunately, there are also various options for installing the solar system. Roof-mounted installation is the classic option that everyone has probably seen on one roof or another. Here, metal frames are mounted on the roof to hold the individual solar panels. With this method, you can easily replace any damaged modules at a later date and are flexible when expanding the PV system. After all, there is no major intervention in the fabric of the building. However, the on-roof installation is visually quite striking and protrudes quite a bit above the actual roof. In-roof mounting, on the other hand, replaces the upper layer of the roof and virtually places the solar panels inside the roof. Visually, this is the more elegant solution. However, the installation is more complex and expensive and should be planned right from the start, especially for new builds. If you want to upgrade your new building yourself at a later date, caution is advised. Discuss your plans with your construction company or the relevant trade to avoid invalidating the warranty for your new roof. Replacing individual solar panels or extending the PV system is also much more complex. Apart from these two options, there are many other individual solutions. A very good first step to find out whether a solar system is worthwhile for you is to Energy advice from the consumer advice center or the regional energy supplier. After specifying your requirements, you will receive a call from SachsenEnergie in which you can discuss your individual ideas with an expert (
Difference between in-roof and on-roof photovoltaic systems
Difference between in-roof and on-roof photovoltaic systems

Legal - Who is allowed to install a photovoltaic system?

Before such a large construction project, it is important to fulfill the legal requirements and to safeguard yourself. We answer important questions that many private individuals have in the course of installing a photovoltaic system.

Registration with the grid operator, in the market master data register and with the tax office

All systems that generate electricity must be entered in the market master data register after commissioning. Non-compliance may result in a fine and the loss of the feed-in tariff. Registration takes place online via the Portal of the market master data register. If you are planning a photovoltaic system that produces more electricity than you consume, a Registration with the network operator for feeding the surplus electricity into the power grid. For more details, please contact your local grid operator. As operating your own photovoltaic system is a commercial activity, you must also register this with your local grid operator. Tax office report. As you make a profit from feeding electricity into the grid, this is subject to income tax. VAT is also payable on both the electricity fed into the grid and the electricity you use yourself.

Excursus: Photovoltaic system for rental apartments?

As the Stuttgart Local Court confirmed in March 2020landlords cannot prohibit the installation of balcony photovoltaics without good reason. The prerequisite for approval is that it is permitted under building law, has been installed professionally and that no damage to the building fabric remains in the event of subsequent dismantling. Do not risk a legal dispute, but speak openly with your landlord. Another alternative is to rent the roof of the building in which the rented apartment is located, or another one. You should also discuss this with the owners.

What does a solar system cost?

First things first: A private photovoltaic system is particularly inexpensive if you can take advantage of a subsidy. The costs of a PV system depend on your own electricity consumption and the output of the photovoltaic system. The higher your electricity consumption, the more solar area you need and the higher the costs. For an exemplary electricity consumption of 4,000 kWh/year, the photovoltaic system should have an output of around 4 kWpeak. This is available from around 8,000 euros . A suitable storage system would also cost around 6,500 euros. The storage capacity that makes sense depends on the installed output of the PV system and is between 5 and 15 kilowatt hours for single-family homes. You can expect to pay between 1,000 and 1,800 euros per kilowatt hour of storage capacity. You should also factor in the cost of installation. In any case, a PV system is a long-term investment. In the vast majority of cases, the costs will only be amortized after a few years. For a complete photovoltaic system with a corresponding energy concept, storage and integration of a wallbox, you should obtain a quote from your local energy supplier such as SachsenEnergie. Assuming an electricity consumption of 4,000 kWh/year and a self-consumption rate of 70%, you can save almost 1,000 euros per year based on the current average electricity price in Germany of 34.96 ct/kWh.

What photovoltaic subsidies are available?

The remuneration for solar power that you feed into the grid is technically a subsidy. The German government is constantly discussing how exactly it should develop in the future. The state banking group KfW promotes renewable energies with a low-interest loan. With the promotional product "Renewable Energies - Standard (270)" promotes systems for generating electricity and heat as well as grids and storage facilities with an effective annual interest rate of just 2.56%. This applies to private individuals as well as companies and public institutions. Some federal states also offer their own subsidy projects. You should find out whether you are eligible for one of these if you want to start implementation as soon as possible, as the funding pots can quickly be exhausted. For example, the EUR 300 million funding pot for the "Solar power for electric cars" program was used up within a day(442 Solar power for electric cars | KfW). In addition to the photovoltaic system, the electricity storage unit and the charging station, the e-car ordered or already available was also a prerequisite. A further 200 million euros are planned for 2024, so it pays to be quick!

Use it yourself or feed it into the grid - a comparison

What is actually more worthwhile, using it yourself or feeding it into the grid? The more solar power you use yourself, the more worthwhile it is to invest in a PV system. In the night of July 5, 2022, the German government agreed on an average feed-in tariff of 8.60 cents per kilowatt hour for solar power from small PV systems in accordance with the EEG. This applies to new systems from 01.01.2023, which is significantly lower than the average 35 cents per kWh that a consumer pays to purchase electricity from the supplier. It is therefore most efficient to consume the solar power you generate yourself. This is the reason why solar power storage systems are such a good idea. This means you don't have to buy expensive electricity at night, but can continue to use the electricity you produce yourself. If possible, self-consumption is therefore always the cheaper and more financially rewarding alternative to feeding electricity into the grid.

Photovoltaic system for the home: the environmentally friendly way to reduce electricity costs and charge your own electric car!

Many people have recently become aware of the topic of photovoltaic systems for private individuals due to their new electric car. This is very pleasing, as you can not only save money, but also generate climate-neutral electricity! Proper planning is the be-all and end-all of such a project. Clarify in advance whether your building is suitable for a photovoltaic system and how much electricity you need. However, it is always most financially worthwhile if you consume the electricity you generate yourself. Due to the dependence on the sun, an electricity storage system is also a good idea, so you can supply your electric car with solar power even in bad weather or at night. The KfW subsidy 442 "Solar power for electric cars" or the KfW promotion 270 for renewable energies also makes such a project attractive. Also keep an eye out for other subsidies from the federal states, these are quickly sold out! For a comprehensive energy concept and personal advice, you should always contact your local energy supplier.
A contribution by Marcel Duparré

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