Quick Answer
For large off-grid installations, microinverters may not be the most economical option. While they offer benefits like easier installation and module-level monitoring, their higher cost per watt can quickly add up, making them less attractive for high-capacity projects. A solar string inverter, on the other hand, can provide a more cost-effective solution for large-scale installations.
Microinverter Cost Structure
Microinverters typically cost between $0.80 to $1.20 per watt, depending on the model and manufacturer. In contrast, solar string inverters can be as low as $0.30 to $0.60 per watt for high-capacity units. For a 10 kW off-grid installation, the difference in cost would be around $1,800 to $3,600 using microinverters, compared to $3,000 to $6,000 using a single string inverter.
System Design Considerations
When designing a large off-grid solar installation, it’s essential to consider the system’s overall efficiency and reliability. Microinverters can provide some benefits in this regard, as they allow for module-level monitoring and can potentially increase overall system efficiency by up to 5%. However, this benefit is often outweighed by the higher upfront cost of microinverters. Additionally, microinverters typically require more wiring and connectors, which can increase installation labor costs.
Real-World Example
A recent project involved designing a 20 kW off-grid solar installation for a remote cabin. The client chose to use a string inverter due to the large system size and the need to minimize upfront costs. The total cost of the system, including the inverter, was around $12,000. If microinverters had been used, the total cost would have been closer to $20,000, a difference of $8,000. While microinverters may offer some benefits, they are often not the most economical choice for large off-grid solar installations.
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