Bild-Dialog-PV yang
2023-01-01 publication

Photovoltaics: Power from above

With a market share reaching almost nine percent of gross consumption in 2021, solar power is the second most important source of renewable energy in Germany. Solar parks and systems installed on private buildings show great potential – which needs to be harnessed quickly and efficiently.


VDE dialog - the technology magazine

Many say that a new era is dawning these days not only in security and foreign policy, but also in energy policy. For example, immediately after the Russian attack on Ukraine, German Finance Minister Christian Lindner (FDP) described renewable energy sources as “sources of energy freedom, because they grant us independence”, making it clear that Germany’s energy policy needs a dose of self-sufficiency. And not only for the sake of climate change mitigation. According to the revised regulations of the German Renewable Energy Act (EEG), photovoltaics are to play an important role in this effort. In the first half of 2022, 11.2 percent of Germany’s electricity came from solar power. Only wind energy provided more green electricity, at 25.7 percent. Photovoltaics are slated to catch up, though. The new EEG 2023 calls for 22 gigawatts of additional capacity to be installed annually up to 2030 – the current goal is a total output of around 215 gigawatts in 2030. By way of comparison, the German government had previously only planned for an annual increase of 4.6 gigawatts. 

The envisioned expansion is no easy task: the war in Ukraine, the global COVID pandemic, and new social distancing measures in China have caused noticeable raw material and supply chain bottlenecks for electronic components. The photovoltaic industry is no exception to this dynamic. For example, SMA Solar Technology AG, a manufacturer of solar inverters, complained in August about a shortage of electrical components and had to slash its business forecast – despite strong demand for its products.


“The potential space for photovoltaics is not the same as the economically feasible potential.” Boris Farnung, Global Head of Power Plants and Systems at VDE Renewables


Solar industry not immune to skilled worker shortage

Boris Farnung, Global Head of Division for Power Plants and Systems at VDE Renewables GmbH, sees even more obstacles for expanding photovoltaics: “The procurement bottleneck is only part of the problem. New solar power systems have to undergo approval procedures that can take a long time. In addition, the industry is striving to build the largest solar parks it can to ensure a good return on investment. Smaller projects get pushed to the back of the line.”

Many problems are also the legacy of failed policy set by past governments. Farnung recalls: “Politicians have not always created a fertile framework for renewable energy sources. This led to skilled workers and tradespeople in Germany moving away from the solar industry.”

The solar expansion requires space. Far less than one might suspect, however, according to the environmental association World Wide Fund For Nature (WWF). For the WWF study “Germany’s Electric Future II – Regionalization of renewable power generation”, the Öko-Institut (Institute for Applied Ecology) and consulting firm Prognos examined the question of how much additional onshore wind energy or solar power it will take to achieve power generation based entirely on renewables by 2050.

In the various scenarios they looked at, the planned expansion of onshore wind energy and photovoltaics occupies up to 2.5 percent of the country’s surface area on average depending on the technology mix and regional spread.

“The Federal Government’s expansion targets will not fail due to a lack of available space for photovoltaics,” says Farnung. “Nevertheless, the technically feasible potential and the potential that is useful in real economic terms are two very different things. Environmental protection issues play a role in this, as do cost-benefit calculations. Agriculture, infrastructure projects and renewable energy also sometimes compete for the same sites.”


Plug-in solar devices: DKE presented an initial draft of the first VDE product standard

Around 200,000 balcony power plants have already been installed in Germany. The available plug-in solar devices, consisting of a solar module, inverter and connection cable, have not yet been certified. DKE presented an initial draft of the first VDE product standard for this technology last fall. 

Up to 70 percent of currently installed plug-in solar devices use the Schuko plug common in household appliances – but these mini-PV systems do not fall into that category. As the electricity is not only received but also fed in, DKE recommends a special plug-and-socket device or comparable concepts.

The product standard for plug-in solar devices aims to describe technical safety requirements for manufacturers and suppliers to work with. It also describes test criteria for proving electrical safety. This provides end customers with evidence of the technical safety and quality of the product. Finally, the standard provides details of the points to note during registration and assembly and what information should be made available to the end customer. The product standard is in the commentary phase, and everyone is free to participate. The standard is to be completed by the end of 2023. Alexander Nollau, Head of Energy at DKE, reassures consumers: “Any devices that are marketed up to then will not be affected by the product standard and can continue to be operated.”

Energy from the sun is cheap to produce – but it’s not without drawbacks

It is relatively cheap to generate solar energy. This is measured by the cost of generating electricity, i.e. the costs spent on converting different forms of energy into electrical power. This includes pre-investment and installation costs, operating and personnel costs, any incurred fuel and disposal costs, and costs for CO2 emissions. According to Fraunhofer ISE, photovoltaics perform well in this sense, although there is a certain spectrum involved. While large open-air plants in southern Germany produce electricity for 3.12 cents per kilowatt hour, electricity from small roof-mounted solar power systems in northern Germany costs almost 11 cents. Electricity from renewable sources will become cheaper overall in the future. Depending on the type of plant, the Fraunhofer Institute forecasts a cost reduction of up to 40 percent for photovoltaics.

However, the informative value of the costs of generating electricity has its limits. Farnung points out that a large number of variables in the equation have to be estimated: “The calculated service life of the system, in particular, can significantly influence the result. The question here is whether the system will ever reach the desired service life. In addition, using cheaper, but inferior materials can have a negative impact on the service life, but can have a positive impact on the calculation of electricity generation costs.”

However, large-scale projects in the Middle East are demonstrating what is already possible with enough sunlight. They are already producing one kilowatt hour of solar power for less than USD 2 cents.


The 2.4-megawatt PV system on the roof of Bundesliga soccer club SC Freiburg’s home stadium is the second largest of its kind in the world. The electricity generated here is sufficient to meet the annual operating requirements.


A football stadium producing 100% of its own power needs

While China and India have photovoltaic power plants with an output of up to 2,200 megawatts, things are understandably more modest in Germany, which is significantly smaller: the VDE-certified Weesow-Willmersdorf solar park in Brandenburg is at the forefront with 187 megawatts. Operator EnBW commissioned additional plants in Brandenburg with an output of 150 megawatts each in the first quarter of 2022. In addition to large solar power plants, however, it is often innovative projects that demonstrate the remaining potential to expand photovoltaics. For example, the soccer club SC Freiburg, which plays in Germany’s Bundesliga, has turned the roof of its stadium into a solar power system. For the 2.4 megawatt project, 6,000 solar modules – “Made in Germany” by Meyer Burger and certified by VDE – were installed on the roof of the Europa-Park Stadium. They will generate about 2.3 million kilowatt hours of electricity per year, covering the stadium’s currently estimated annual electricity demand while emitting no CO2. The system, implemented by project developer and operator badenova, has been inaugurated and is currently being reviewed intensively to gain the designation as a VDE-certified PV power plant. 

Solar energy production in private households is also not insignificant – although the trendy balcony power stations installed in recent months, which virtually anyone can use without their own roof and without a fixed installation, are not yet included in the statistics. According to the international market research and consulting firm EUPD Research, the number of PV systems on detached and semi-detached homes reached 1.3 million at the end of 2020. A huge total of 11.7 million properties of this kind are reportedly suitable for photovoltaic systems nationwide.

Electricity generation is (once again) attractive for private households

“The potential on the roofs of private homes is immense. However, there are many individual circumstances on each site that you have to address. Not every roof is suitable for solar modules. To avoid causing disappointment here, we need qualified technicians who also have expertise in electrical storage systems, charging infrastructure and heat pumps,” Farnung says. Due to the drop in feed-in compensation and high regulatory hurdles, the investment was not attractive for private households for a long time. Things are already changing, though. The number of relatively small roof-mounted systems is growing steadily. They have almost doubled their share among newly installed PV systems – from 18.8 percent in 2018 to 36.2 percent in 2021. Fraunhofer ISE also attributes this to the elimination of the levy obligation on self-consumption. The newly amended Renewable Energy Act aims to give this development a further boost: rooftop systems that feed their electricity entirely into the grid will once again receive higher compensation of up to 13.8 cents per kilowatt hour.

GERD RÜCKEL is a freelance journalist in Friedrichsdorf (Hesse), Germany, who specializes in finance, green investments and science.

Read now: the VDE dialog E-Paper

Business man use computer tablet with cloud computing diagram show on hand.
ic36006 /

Register for our digital magazine and look forward to extended coverage with reports, news and opinions from the industry - free of charge, of course! 

Read more