There is great interest in photovoltaic systems to generate their own energy in order to counter the massive rise in gas and oil prices. Independence from gas and oil supplies from Russia is also a motive for many people due to the current war in Ukraine.
Photovoltaic systems generate renewable energy. However, few people are aware that the solar modules in these systems contain heavy metals that can pollute the environment. With the politically demanded“energy transition“, fossil and climate-damaging main energy sources such as gas, oil and coal are to be increasingly replaced by renewable energies. Renewable energies primarily include photovoltaics, wind energy as well as biogas and hydropower. Photovoltaics, which use solar radiation to generate energy can also end the strong dependence on fossil fuels. In terms of renewable energies, photovoltaics is an important technology in which Germany has made a decisive contribution.
Expansion of energy coverage systems
In order to cover Germany’s energy requirements as far as possible from renewable energies (RE) , photovoltaic capacity in Germany must be further expanded. In order to meet the interim target for the year 2030 of the EEG 2021 (Renewable Energy Sources Act), the share of renewable energies should already cover 65% of gross electricity consumption.
New solar installations with photovoltaics are among the cheapest renewable energy technologies. In 2020, photovoltaics covered around 9.2% of gross electricity consumption in Germany. All renewable energies accounted for 45% of gross electricity consumption. There were two million photovoltaic systems at the end of 2020. After wind energy, photovoltaics accounts for the second-largest share of total renewable electricity generation in Germany.
Solar power system
The photovoltaicsystem (PV system or solar generator) is a solar power system. In the photovoltaic system, the solar cells convert the solar radiation into electrical energy into electrical energy. This energy conversion is referred to as photovoltaics.
The photoelectric effect of the solar cells, which are connected to the solar modules, is used for this conversion. The energy generated can be used directly. The electricity is then stored in accumulators or fed into power grids. The DC voltage generated is converted into AC voltage before being fed into the grid. For rooftop systems, the rated output is in the single-digit kilowatt range, for commercial rooftop systems up to the megawatt range. In addition, solar power generated during the day can also be used at night if it is stored optimally. The generation of solar power is subject to daily and annual fluctuations as well as weather influences.
Photovoltaics are also used for mobile applications and without a connection to a power grid as stand-alone systems. This is used, for example, for the operation of satellites, solar vehicles or solar airplanes. Other examples include solar systems for camping, solar lights, electric pasture fences and parking ticket machines.
Forms of investment
Rooftop system
The most common type of photovoltaic system is the rooftop system. The installation of a rooftop system is generally simpler and cheaper than that of an in-roof system. In this case, the building supports the substructure of the photovoltaic system. The solar modules attached to the substructure should be aligned in such a way that the highest possible or most constant energy yield is guaranteed throughout the year. For a maximum energy yield the roof should face south and have an angle of inclination between 30 and 45 degrees. In the case of pitched roofs, there is no need for a substructure to align the solar surfaces, but this roof pitch is often not ideal for the energy yield.
In-roof system
With this type of system, the photovoltaic system replaces parts of the building envelope. It therefore replaces part of the façade cladding or roof covering. These systems integrated into buildings are generally less ventilated, which reduces the efficiency of the system.
Environmentally harmful substances
The solar modules in most photovoltaic systems are often contaminated with water-soluble substances that are washed out with the rain. Various pollutants are found in photovoltaic systems, such as heavy metals in the lead and cadmium compounds. These are used as semiconductors.
These heavy metals can be washed out of the modules over a long period of time byleaching. This is particularly the case if the cover glass is broken, edge seals are damaged or modules have been taken apart. Therefore, these damaged photovoltaic modules should not simply be disposed of with residual waste or landfill, but via a certified disposal company. Damaged modules should also not be exposed to the weather for long periods of time.
In 2006 , the European Union banned the use of toxic heavy metals in the RoHS Directive for the electrical industry. This applies in particular to solder containing lead, which is widely used in photovoltaic systems. However, photovoltaic modules have so far been exempt from this regulation.
The majority of photovoltaic systems worldwide are based on silicon technology. There are also systems using thin-film technologies with semiconductors made of cadmium telluride or gallium arsenide. Perovskite-based solar modules are also contaminated with pollutants. They contain the environmentally harmful heavy metal lead and are less durable. Most solar module technologies have solder bands that contain lead in the solder. Only modules made of amorphous silicon are free of pollutants as long as no soldering tapes containing lead are used. According to researchers, lead-containing solder could be replaced by lead-free compounds.
The GSA Messgerätebau GmbH will be happy to provide you with comprehensive and competent advice on questions relating to harmful substances and offers a wide selection of suitable measuring devices for a wide range of measuring of harmful substances via its GSA measuring devices online store. We will be happy to advise you on your questions regarding sampling with the appropriate measuring devices.
Photovoltaic systems: Answers to frequently asked questions
1. how effective are the current recycling methods for solar modules?
- Some processes can recover a large proportion of heavy metals, while others are less effective.
2. Are there legal regulations for handling heavy metals?
- There are regulations for handling harmful substances in solar modules. In many countries, manufacturers of solar modules must ensure that their products can be safely disposed of or recycled.
3. what can individuals do to reduce the problem of pollutants?
- To mitigate this, consumers can opt for solar modules that contain less harmful heavy metals. Also by ensuring that their old modules are properly recycled.
4. Are there alternatives that do not contain metals of concern?
- There are various alternatives to this. Some manufacturers are working on the development of solar modules that do not require the use of harmful substances such as lead and cadmium.
Sources:
Image source: 123rf.com © vchalup, image no. 84246650
www.bmwk.de/Redaktion/DE/Dossier/erneuerbare-energien.html
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