Module inverter or string inverter: Which system maximizes the efficiency of your solar system?

Choosing the right inverter is a key factor for the performance and cost-effectiveness of your photovoltaicPV system. In this article, we compare module inverters (also known as micro inverters) with string inverters in terms of their technical properties, areas of application and economic benefits. The aim is to provide you with well-founded information so that you can optimally increase the energy yield of your solar system.

Importance of inverter selection for your solar system

Module inverters and string inverters differ fundamentally in terms of design, function and area of application. These differences have a direct influence on the efficiency, fire risk, safety and flexibility of your PV. While module inverters are a decentralized solution and optimize each individual solar module individually, string inverters work centrally and are particularly efficient on homogeneous roof surfaces with little shade. Module inverters offer clear advantages, especially for complex roof structures with different angles of inclination or partial shading from chimneys, buildings or trees, for example. The specific lighting conditions and the nature of a roof are therefore decisive factors when choosing a suitable inverter system.

Module inverters: Technical basics and advantages

Module inverters, such as those from ATMOCE, convert the direct current into alternating current directly at each solar module. This decentralized technology enables individual power adjustment for each solar module, which leads to a significant increase in energy yield, especially in sub-optimal conditions such as shading or different orientations. This significantly increases flexibility in the arrangement of the modules, as each module works autonomously and system losses are minimized.

Another technical advantage is the low DC voltage on the DC side (maximum 60 volts, corresponding to the module running voltage), which reduces the risk of fire and therefore increases safety. In addition, many module inverters have integrated safety mechanisms such as rapid shutdown, which enable rapid shutdown in an emergency. Arc detection is not necessary due to the low system voltage on the DC side. Decentralized monitoring of the individual modules using comprehensive monitoring functions allows precise analysis of energy generation and facilitates maintenance and fault diagnosis.

Module inverters are particularly suitable for complex roof structures with varying tilt angles and orientations as well as partial shading. They make it easy to expand the system if the power requirement increases or the system is to be extended. Thanks to their high efficiency and improved long-term performance, module inverters are an economically attractive solution, particularly in urban environments or with fragmented roof areas.

String inverters: Technical basics and areas of application

String inverters bundle the direct current of several solar modules connected in series and convert it centrally into alternating current. This technology is particularly efficient and cost-effective for large, homogeneous systems with little or no shading. The DC voltages on the direct current side can be up to 1,000 volts or even 1,500 volts, which places increased demands on the installation and safety measures.

String inverters are characterized by their robustness and reliability, but are susceptible to power losses if individual modules are shaded or have different outputs. As the output of a string is determined by the weakest module, partial shading or age-related degradation of individual modules can significantly reduce the overall output. For detailed monitoring and optimization, string inverters often require additional components such as power optimizers, which can increase the overall costs.

Economic analysis: a comparison of costs and benefits

When choosing between module inverters and string inverters, economic aspects play a key role. Module inverters generally incur higher acquisition costs and tend to require more installation work on the roof, but faster electrical installation at the distribution board. However, these additional costs are often offset over the service life of the system by the increased energy yield and improved flexibility in complex roof conditions. In addition, module inverters often eliminate the need for additional investment in optimizers or monitoring hardware, as these functions are already integrated.

String inverters score points with their lower acquisition costs, which makes them particularly attractive for large, unshaded systems. However, yield losses due to shading and a lack of individual module monitoring can impair economic efficiency. Furthermore, additional devices are usually required for comprehensive system monitoring, which in turn incur costs.

Inverter cost-benefit analysis:

Technical and installation-related requirements

The technical conditions and installation requirements differ significantly between the two systems. Module inverters benefit from the low DC voltage, which increases installation safety and reduces cabling requirements. The decentralized AC cabling from the roof to the inverter also simplifies installation and minimizes risks.

String inverters work with high DC voltages, which require precise and professional installation in order to avoid safety risks such as arcing or short circuits. Compliance with the installation instructions is particularly important here to ensure safe and reliable operation.

Selection criteria for the optimum inverter system

The following factors should be taken into account for the optimum choice of inverter:

• Number and orientation of the solar modules
• Existing shading and roof structure
• Efficiency and performance class of the devices
• Manufacturer's warranty and customer service
• Integration of monitoring and smart grid technologies

Conclusion: Increased efficiency through the right choice of inverter

The choice between module inverters and string inverters has a significant influence on the efficiency and cost-effectiveness of your solar system.

Thanks to their individual module optimization and increased operational reliability, module inverters offer clear advantages for complex and shaded roof structures. They enable maximum yields, even on small roof areas, flexible system expansion downstream and improve energy yield in the long term.

String inverters impress with their low acquisition costs and proven robustness, but are particularly suitable for large, homogeneous systems without shading.

Ultimately, the decision should be based on a comprehensive analysis of technical conditions, economic aspects and individual requirements in order to ensure maximum energy efficiency and a sustainable investment.

Discover the module inverters from ATMOCE in our online store