Photovoltaic systems

A brief overview of the history of PV

In 1839, Alexandre Edmond Becquerel stumbled upon the photoelectric effect during his experiments. In 1907, Albert Einstein provided the first theoretical explanation for it, and through continuous advancements in semiconductor technology by Jan Czochralski in the early 1900s, the technology gained real momentum around 1950. Development has continued ever since, with basic research contributing significantly to efficiency gains, and semiconductor applications expanding enormously. In March 1958, photovoltaics were used for power supply for the first time in the USA, and history took its course.

Etymology of the term "photovoltaics"

The basic principle of a photovoltaic system is simple to explain. The word photovoltaics is derived from VOLT and the Greek word for light, phos (genitive photos). The word VOLTA comes from Alessandro Volta, the pioneer of electricity studies and inventor of the battery. The letter "V" stands for the unit VOLT, which represents electrical voltage.

Basic function in brief

The underlying principle relies on sunlight shining onto solar cells. Interconnecting many solar cells forms a PV module. Sunlight excites electrons in the solar cells, causing them to move and generate direct current (DC) electricity. However, DC power cannot be used directly in a standard household in this form.

Standard household electrical grids run on alternating current (AC) at 230 volts and a frequency of 50 Hz. This means the DC power generated by the PV modules must be converted into AC power. This conversion is handled by the inverter.

In addition to converting electricity, the inverter performs several other functions. It regulates feed-in into the public grid and monitors vital system parameters. If power grid disruptions occur, the inverter can disconnect the PV system from the grid to protect home electrical components from damage.

The inverter also controls, monitors, and manages the charging and discharging of a battery storage system.

Along with minor modifications to the main distribution panel to accurately measure grid feed-in and properly protect the system in emergency situations, the PV system is fully operational.

Because every ray of sunshine counts!

Naturally, you could just mount PV modules on a roof, balcony, barn, or carport and get started. In principle, yes, but proper PV planning should always account for site conditions. In most cases, available space is limited, making smart layout planning essential.

A key aspect of planning is module orientation. Just because the sun shines brightest in the south does not mean facing everything south is the best choice. As a general rule, and provided local conditions allow, you should plan module distribution according to the sun's trajectory.

If possible, factor in the morning sun by facing modules east. Additional modules should face south, and for the late afternoon, south-west or west. This optimizes the system's overall yield. You produce less right at midday, but generate more in the morning (east orientation) and late afternoon (west orientation). As a result, power production is distributed more evenly throughout the day, smoothing out the midday peak.

PV module orientation should also be tailored to your family's daily routine. If everyone leaves the house at 6:00 AM, pointing panels east is not strictly necessary. If lunch is cooked at midday, the kids come home from school, do homework, and play video games while the father works from home, then a south and south-west orientation is the smarter choice. For the late afternoon and evening, placing a few panels facing west always makes sense, provided there is no severe shading.

Shading is another major consideration when planning a PV system. If individual modules experience localized shading throughout the day—from power poles, trees, or other obstacles—you should install power optimizers. Without them, modules producing less due to shade would drag down the output of the unshaded panels. Power optimizers make it possible to fine-tune the PV system for maximum output throughout the day, accounting for all shading and obstacles.

Making good even better!

Ultimately, a PV system should be more than just a home power generator or surplus feed-in source. A PV system is only as efficient as how well you adapt it to your lifestyle. If you purchase a PV system and store unused electricity in a battery, you feed less into the public grid, but keep self-generated power available for the night. You can run your TV, laptop, or electric stove for evening cooking using stored solar energy. Generating, storing, and accessing electricity for off-peak hours on your terms saves money on power you would otherwise have to purchase from the grid. Then there is home EV charging, which is a topic for its own dedicated blog post. Check it out.

Conclusion

There is plenty to consider when choosing a PV system for self-consumption or surplus feed-in. Thorough planning tailored to your site increases efficiency, maximizes overall system yield, and represents a crucial step toward energy independence. We at Conversio Energie GmbH have planned and built more than 2,500 PV systems with a total output exceeding 110,000 kW. This underscores our expertise in PV systems and renewable energy technologies. See for yourself and get in touch with us.