Comparison of String Inverters and Central Inverters for Large Arrays?

Advantages of String Inverters for Large Arrays

String inverters are ideal for large solar arrays due to their modularity, which allows for the addition or removal of modules as needed. This scalability reduces the need for costly equipment upgrades and minimizes downtime during installation. In a 500 kW solar array with 200 strings, a string inverter can be installed for each string, simplifying the installation process and reducing overall costs.

Efficiency and Monitoring with Central Inverters

Central inverters, on the other hand, offer improved efficiency due to their ability to optimize energy production across the entire array. They also provide enhanced monitoring capabilities, allowing for real-time data collection and analysis. However, central inverters often require more complex installation, including a dedicated transformer and larger wiring connections, which can increase upfront costs. To mitigate this, a well-designed central inverter system can be configured to maximize energy output, with a 10% increase in efficiency possible in a system with a 500 kW central inverter.

Maintenance and Cost Considerations

String inverters generally offer lower maintenance costs due to their modularity and ease of access. In contrast, central inverters often require more complex maintenance procedures, including accessing the inverter from the roof or a remote location. Additionally, string inverters typically have a lower upfront cost, with a 20 kW string inverter costing between $10,000 to $15,000, while a 20 kW central inverter can cost upwards of $25,000.