Photovoltaics have established themselves as an important and sustainable source of energy in Germany. But is everything that glitters gold? In this article, we list all the advantages and disadvantages of photovoltaics and solar systems and then explain them in detail.

All advantages and disadvantages of photovoltaics as a table

What are the advantages of photovoltaics?

In addition to the obvious advantages, such as climate friendliness and cost savings, the use of photovoltaics has many other benefits.

saving on electricity costs 

The biggest advantage of photovoltaics is the cost savings. While electricity prices are constantly rising, a PV system enables long-term energy production at consistently low costs. The purchase costs pay for themselves after an average of eight to nine years. 

Electricity price development 2001 - 2024

With an annual consumption of 4,500 kWh, a 5 kWp system can save around €8,000 after 20 years. If a power storage unit is also used, savings of up to €17,000 are possible. 

Example:

• Electricity price from the grid: 28 cents per kWh (as of February 2024 for new customers)
• Annual electricity price increase: 6%
• Feed-in tariff: 8.11 cents per kWh (as of February 2024)

Constant energy source

In contrast to coal and gas, the sun is an inexhaustible source of energy. Fossil fuels will one day be exhausted. In contrast, the sun is unlimited and available free of charge. However, in order for the photovoltaic system to generate electricity reliably over many years, it is important that high-quality components are used and that the installation is carried out by professionals. 

PV modules last 30 to 40 years

The product guarantees for PV modules are often 20 to 30 years. In reality, solar modules even have a lifespan of 30 to 40 years. This means that electricity production and the saved electricity costs are guaranteed for this period.

Environmentally and climate-friendly

The use of photovoltaics is 100% CO₂-free and actively contributes to reducing environmental impacts. Electricity production does not require fossil fuels, which minimizes emissions. Even taking into account the manufacturing process, silicon extraction and transport, which emit CO₂, a PV system pays for its CO₂ balance after 1.3 years, according to the Fraunhofer Institute, and thus makes an important contribution to environmental protection.

CO₂ emissions from energy sources in gkWh

Photovoltaic costs are falling more and more

The Prices for PV systems are falling continuously and are currently at their lowest level in years. In 2010, the cost of photovoltaics was around €3,500 per kWp. In 2015, prices fell below €2,000 per kWp for the first time and are currently around €1,200 per kWp.

photovoltaic price development

This sustained decrease in costs is the result of technological advances, the scaling of production and increasing demand. In particular, the prices for PV modules and electricity storage have fallen sharply. This positive development is making photovoltaics increasingly attractive and economically viable for private households.

independence from electricity suppliers

With a photovoltaic system, you are more independent from your electricity supplier. Even in the event of a power outage, your own electricity production can be maintained. In addition, a PV system not only protects against supply gaps, but also against high electricity prices. These have been rising by an average of around 61% annually since the beginning of the 2000s. 

The installation of a power storage system also enables greater self-sufficiency, as excess electricity is stored for later use. This leads to a higher self-consumption rate of solar power and further savings. Independence from external energy sources continues to increase, and your own solar power is available even at night or on cloudy days.

Self-consumption and self-sufficiency with 4,000 kWh consumption

feed-in tariff

The feed-in tariff is a financial remuneration for PV system operators who feed their surplus electricity into the grid. Although the remuneration has fallen in recent years, it still offers an additional source of income and contributes to the profitability of the photovoltaic system. The feed-in tariff is currently 8.11 cents per kWh fed in for PV systems up to 10 kWp and 7 cents for systems up to 40 kWp. The amount of the feed-in is reduced by 11% every 6 months.

electric car charging

With a wallbox, you can easily charge an electric car for free at home. This means you save money and at the same time increase the profitability of your solar system. Because the more solar power you use yourself, the more worthwhile photovoltaics is.

Remember that the performance of the PV system with a wallbox should be dimensioned a little larger. Normal photovoltaic systems on a single-family home have a size of 5 to 10 kWp, depending on the power consumption. In order to also charge your electric car and drive 15,000 km a year with it, you should plan the solar system 2.5 kWp larger. 

funding opportunities

There are various funding options available at local, state and national levels for the purchase of photovoltaic systems. These grants and low-interest loans make the investment easier and make photovoltaics more financially attractive.

At the state level, you can access the KfW loan The funding program 270 "Renewable Energies - Standard" supports the financing of photovoltaic systems and battery storage systems. The funding does not only cover the acquisition costs, but also the planning, design and installation of the system. 

For funding and grants at local and state level, you should contact your city or district. They often pay additional attractive grants per kWp.

Purchase and solar power are tax-free

The 2022 Annual Tax Act introduced comprehensive tax exemptions for operators of PV systems up to 30 kWp. The income from self-consumed solar power and the electricity fed into the grid is now tax-free and no longer has to be declared in the income tax return. This also applies retroactively to 2022.  

Before this new regulation, an exemption was only available upon application and only for systems up to 10 kWp. This regulation was also hobby regulation called. 

VAT for the purchase and installation of a PV system and for electricity storage will also be abolished from 2023. This applies to all PV systems on residential buildings up to 30 kWp.

Photovoltaics is low-maintenance and robust

Photovoltaic systems are characterized by robustness and low maintenance The solar modules are mechanically stable and can withstand a wide range of weather conditions for many years. In addition, maintenance is only required every two to four years. Regular cleaning of the modules, checking of the wiring and, if necessary, replacing older components can be done by the owner himself. The costs remain low. 

Flexible systems in any size

Photovoltaic systems are flexible and scalable. They can be planned in any size, whether for private homes, commercial businesses or industrial applications. It doesn't matter whether it is a gable, flat or hipped roof - there is a suitable substructure for every shape. There are also flexible options in terms of the type of installation, such as the classic roof-mounted installation, in-roof installation or building-integrated photovoltaics. 

No noise or odor nuisance

Unlike some conventional energy generation methods, such as burning fossil fuels, photovoltaic systems do not produce any noise or unpleasant smells. Energy production is silent and environmentally friendly. 

Free disposal of modules

The environmental impact of photovoltaic systems extends over their entire life cycle. After their long operating period, the solar modules can be disposed of free of charge at your local recycling center disposed of and recycledMost modules contain recyclable materials such as glass, aluminum and of course the silicon of the solar cells. 

future technology

Photovoltaics is a key technology for a sustainable energy future. Continuous research and development in this area is helping to ensure that the efficiency of solar modules is constantly increasing while costs are falling. 

Great progress is being made in research into power storage. The old lead-acid batteries have been replaced by lithium-ion batteries. These modern batteries not only offer a higher energy density, but also a longer service life and improved performance. 

increase in the value of the property

Installing a photovoltaic system can increase the value of a property. Access to green energy and the prospect of long-term energy savings make a building more attractive to potential buyers or tenants. 

What are the disadvantages of photovoltaics?

Although photovoltaics has many advantages, it also has some disadvantages.

High investment costs

The main disadvantage of photovoltaics is the initial investment costs. The purchase and installation of a solar system on a single-family home will cost between €7,000 and €12,000 in 2024. With an electricity storage system, the costs rise to €10,000 to €18,000. Although photovoltaics pay for themselves over time through savings in electricity costs, the investment costs still have to be paid first.

Weather-dependent yield

The yield of photovoltaic systems is highly dependent on the weather. This drops rapidly, especially when the sky is cloudy or it is raining. This leads to variable electricity yields, which affects the reliability of the energy supply. 

Less electricity in winter

In winter, the amount of sunlight is significantly lower, which affects electricity production. The short duration of daylight and the flatter angle of radiation have a negative impact on the efficiency of the solar cells. In winter, you will therefore have to rely more on mains electricity. 

Specific PV yield per month in kWh/kWp

degradation

The performance of solar cells decreases over time. This process of degradation means that after years of use, solar modules no longer have the same efficiency as they did at the beginning. Most solar manufacturers offer a so-called performance guarantee. This guarantees that the modules will still achieve a certain percentage of their original performance after a period of 25 to 30 years. These are usually values between 80 and 90%.

Not all roofs are suitable

Not every roof is suitable for the installation of photovoltaic systems. Various factors such as orientation, slope, shading and structural stability of the roof can influence the efficiency. 

When planning your PV system, you should consider the orientation and roof pitch. A south-facing orientation achieves the greatest electricity yield, but even with deviations to the east or west or even an east-west system, you can still achieve up to 85% of the yield of a south-facing orientation. An east-west system even has the advantage that both sides of the roof can be covered with modules.

If shading occurs, so-called MPP tracker (Maximum Power Point Tracker) can be used. These optimize the energy yield by adjusting the optimal operating point of the solar modules and thus minimize the effects of shading. The structural stability of the roof is of course essential for the installation of PV systems. It should be noted that older roofs may need to be reinforced or modernized to bear the additional load of the solar modules.

space requirements

Installing solar systems requires space, especially for larger systems. For example, a 4-person household with an annual consumption of 4,000 kWh requires a 6 kWp photovoltaic system to cover its needs. This requires a roof area of 40 to 50 square meters. 

Wear parts such as inverters

Photovoltaic systems contain components such as inverters or power storage units that wear out over time. These wearing parts must be serviced or replaced periodically, which can cause additional costs and potential downtime. The lifespan of inverters is around 20 to 25 years. They must therefore be replaced once during the lifespan of the PV system.

The same applies to inverters: the higher the quality, the better the lifespan and performance. Cheap models often only come with a product guarantee of 5 or 10 years, while reliable models often offer 20 to 25 years. 

Not everyone finds a PV system on the roof aesthetic

Aesthetic concerns can be a disadvantage, as not everyone finds PV modules on their roof appealing. However, the days of deep blue, polycrystalline solar modules are over. Nowadays, almost only black, monocrystalline modules are installed on house roofs. These are also often available in full-black variantswhere the modules and frames are completely black. A much more attractive solution for solar energy.

Parts such as power storage are not 100% environmentally friendly

The use of lithium cobalt oxide storage raises ethical issues related to cobalt mining. This is mined in particular in countries such as the Democratic Republic of Congo, where working conditions are often precarious and child labor and human rights violations are widespread. 

Mining also has an impact on the environment. Consumers should therefore consider sustainable and ethical options for their power storage. It is therefore better to opt for a lithium iron phosphate storage device. Iron phosphate is a natural mineral and not a heavy metal like cobalt.

Solar energy can only be stored for a limited period of time

Although the storage capacity of electricity storage systems is increasing, solar energy can only be stored to a limited extent. During long periods without sufficient sunlight, the stored electricity can be exhausted, requiring a return to grid power. 

In addition, the power cannot be stored forever, but only for a few days, depending on the model. This is due to the natural self-discharge of the battery. It is therefore generally recommended to carry out regular charging cycles. This way, the battery can be kept in optimal condition and its capacity can be fully utilized.

Not always top environmental balance

Photovoltaic modules made in China have a less favorable climate footprint than European modules. This is due to the increased use of fossil fuels in China. This leads to about twice as much CO2 emissions during production, which extends the "energy payback time" accordingly. In addition, the transport of the modules from Asia to Germany causes another not insignificant amount of CO2 emissions.

It should also be noted that PV modules can contain small amounts of harmful substances. For example, silicon modules contain lead and cadmium can be found in thin-film modules. 

Ethical production not always traceable

Ethical manufacturing of photovoltaic panels can be problematic, particularly in relation to the mining of silicon, a key element in panel production. China is one of the largest silicon producers and there are concerns about unethical practices, including forced labor. There are suspicions that Uighurs in Xinjiang are involved in silicon production. Reports of human rights abuses reinforce these concerns. 

How does photovoltaics work? 

Photovoltaics is a process in which sunlight is converted directly into electrical energy. Solar cells, which are made of the semiconductor material silicon, are responsible for this. These absorb the photons from the sunlight, which releases electrons and generates an electrical current. The electrical current is then passed through the metal contact on the back of the cell and on to the inverter. This converts the solar direct current into the alternating current used in the home.

What alternatives are there to photovoltaics? 

There are various renewable energy sources that are alternatives to photovoltaics, such as wind power, hydropower and biomass. Wind turbines use the kinetic energy of the wind, hydropower plants convert water currents into energy, and biomass plants use organic materials to generate energy. Each of these technologies has its own advantages and disadvantages. Choosing the best energy generation technology for your home depends on location, resource availability and specific energy needs.