Sustainable Energy from the Sun: The Power of Photovoltaics
Author: Michael Vogel
Photovoltaics is booming – and with it, the demand for quality and safety is growing. DEKRA provides comprehensive testing and expert assessments, particularly for major-scale installations. This commitment has repeatedly proven indispensable.
The global market for photovoltaics (short: PV) is growing rapidly and steadily: in 2024 alone, installed capacity rose by 600 gigawatts to 2.2 terawatts worldwide. These are the figures compiled by the International Energy Agency (IEA), as part of its annual report on the development of the global photovoltaic market within its 'Photovoltaic Power Systems Programme'. It took almost 70 years to reach the first terawatt of installed PV capacity, but only two years to install the second terawatt, between 2022 and 2024, according to the IEA. With more than one terawatt, almost half of the installed capacity is located in China. In the EU, just under 63 gigawatts were newly installed in 2024, most of it in Germany (16.7 gigawatts) and Spain (7.5 gigawatts). Over 25 countries can cover more than ten percent of their national energy demand with their installed capacities, with half a dozen of them operating at around the 20 percent mark. This makes photovoltaics one of the
pillars of the energy transition
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According to the IEA, photovoltaics accounted for more than three-quarters of the world's installed renewable power generation capacity at the end of 2024.
Where is photovoltaics used?
In addition to private households installing balcony or roof photovoltaics, industry is also driving forward photovoltaic installations: namely on commercially used building roofs and in open spaces. While committed individuals and companies were initially the trailblazers behind the PV boom, with investment in the systems and their ownership and operation lying entirely in the same hands, the current boom is also leading to new utilization models. One example is roof space being leased to an operator, who in turn installs the systems with money from investors. The owner of the roof space then receives rental income.
DEKRA services in the photovoltaics sector
“Naturally, the proper installation of photovoltaic systems is important regardless of their size,” says Anja Foremny, “but in the case of larger systems, this takes on additional significance due to the involvement of investors, installers, and operators, as liability issues also come into play.” Foremny is a product manager for electrical engineering at DEKRA and also a publicly appointed and sworn expert. DEKRA supports photovoltaic projects with testing and assessment expertise in various European countries: starting with planning and commissioning and continuing through to recurrent testing, depending on requirements. “The plant sizes we are involved with start at around 50 kilowatts of installed capacity,” says Foremny. However, they can also be significantly smaller, for example when it comes to the sale of an existing photovoltaic system.
Photovoltaics refers to the technology used to convert sunlight directly into electrical energy. The term is composed of the Greek word phōs (“light”) and the unit volt for electrical voltage. The foundations of this technology date back to the 19th century, when the photoelectric effect, whereby light releases electrons from a material, was discovered. Today, this technology is used in millions of solar modules worldwide, making it one of the pillars of sustainable energy supply.
Whether on the roof or on a megawatt scale, photovoltaics has long been more than just a trend; it is a central building block for a sustainable future. DEKRA ensures that this technology remains not only efficient, but also safe and reliable. Discover our
services related to photovoltaics.
https://www.dekra.com/en/how-to-produce-and-reuse-renewable-energy-safely/
Planning photovoltaic systems: What to consider
In the field of planning, services include the assessment or preparation of the planning documents. Do the electrical installations meet the requirements of existing standards, for example, in terms of load control or grid feed-in? Is the roof on which the system is to be installed laid out to withstand such loads? Does the fire protection concept comply with the applicable standards? “During this phase, we also carry out yield assessments, if necessary,” says Foremny, “where we check whether the calculated yield is realistic.”
DEKRA also supports photovoltaic projects during the construction phase. “During installation, we can prevent defects that would be costly to rectify afterwards, such as in the cabling of the modules,” says Foremny. In addition to electrical safety, the portfolio also includes fire protection and lightning protection, among other things. “If we were not involved in the planning, we also check all planning documents during construction supervision.” Finally, DEKRA can check the installed photovoltaic modules for proper functioning.
This involves thermal imaging of the modules. “This allows us to identify areas that get unusually hot, which can be an indication of damage to the module,” explains Foremny. “We can also measure the current and voltage of the interconnected modules, while simultaneously recording the incident solar radiation and the temperature at the modules.” How much electrical energy a solar module actually generates always depends on the amount of incoming sunlight at that moment, of course, but also on the temperature of the modules.
Photovoltaics: installation, costs, and important tips
“For existing systems, we can continue to examine many of the issues that arose during planning and commissioning,” says Foremny. “From electrical safety and fire protection to the stability of a system, but of course also how actual values for current, voltage, and power turn out.” Especially when the yield of a system is below the expected value, large installations always involve a lot of money.
However, the boom in photovoltaics also has its downsides when it comes to implementation. “Photovoltaic systems generate direct current, which is converted into alternating current by the inverter so that it can be fed into the grid,” explains Foremny. In Germany, for example, installations on the alternating current side may only be carried out by a registered electrical contractor. However, there is no corresponding regulation on the direct current side. “Currently, many people believe that they can install photovoltaic systems,” says Foremny. “Unfortunately, it turns out that only a few of them are able to do it properly.”
This problem will grow even bigger as, in the case of many existing systems, there is no sufficient documentation. “How is an electrician supposed to inspect a system if, say, the company that installed it no longer exists? Many companies disappeared from the market after a few years.” Foremny therefore advises investors and operators not to focus solely on cost when selecting a provider. After all, “an installer who complies with all legal requirements has to put in more effort, which is naturally reflected in the cost.”