Are Solar Optimizers Worth It?

Advantages & disadvantages of micro-inverters & power optimizers

Centralized string inverters continue to be the most popular technology choice in the United States for solar panel rooftop systems. Nevertheless, they are gaining popularity quickly thanks to the advantages provided by micro-inverters and power optimizers (often referred to as module-level power electronics, or MLPEs).

Micro-inverters and power optimizers offer similar advantages, but they do work differently. Both are installed next to individual solar panels, and whether one or more of your solar panels are shaded avoid performance problems. The main difference is that micro-inverters transform the DC electricity produced by your solar panels into the AC electricity used by your household appliances, thus minimizing the DC electricity “condition” until it is sent to a central inverter.

Advantages of micro-inverters & power optimizers

MLPE technologies offer the following advantages over centralized string inverters:

• When one of the solar panels in a system is underperforming, MLPE systems ensure a sufficient amount of power is still provided by the system. Total system power output will fall sharply with a central string inverter if one single panel stops generating electricity. With MLPE systems, the others will still continue to generate electricity if one panel fails.
• They are a good choice to deal with “complicated” roofs facing different directions. Panels in the same row will have the same orientation with row inverters so that each one has the same power output. However, the overall production of solar power will drop dramatically, as one panel that produces less power will reduce the output for the entire series.
• They allow you to track the output of individual solar panels, typically through a web portal or smartphone app. It allows for simple problem detection and fast troubleshooting.
• These more effectively convert DC power to AC power than string inverters, and help to optimize total solar system power output. With the same number of panels, this means more power generated.
• These usually come with longer warranties than string inverters–when combined with solar panels for up to 25 years. String inverters are usually guaranteed for 10 years and should generally stay in service for about 15 years until they require replacement.

Note that while there are more powerful micro-inverters and power optimizers, they are not always a better investment. When you pay considerably more to get a device with micro-inverters or optimizers, you will get more power out of your panels but it does not necessarily translate into a better return on investment or shorter payback period. 

Disadvantages of micro-inverters & power optimizers

The potential disadvantages of micro-inverters and power optimizers have to do with maintenance and reliability, rather than how well the devices convert DC electricity to AC.

• MLPE technologies have higher costs when compared to string inverters, because more pieces of equipment must be used.
• More equipment may mean a higher likelihood of breakdowns. The drawback is that a device with a string inverter requires fewer pieces of high-tech equipment, while string inverters can not cope with shading as well as MLPE technologies.
• MLPE devices perform their function in a very harsh environment. Your roof for the entire year is exposed to the elements. Through rain, snow, and heat, all or most of the essential equipment sits on the roof with micro-inverter and power optimizer systems. String inverters are usually positioned off the wall, by contrast.
• Maintenance and replacement may entail additional effort. When an issue occurs, a contractor may have to reach the roof to make repairs. That costs you money, depending on your maintenance plan and warranty.

A luxury commodity is micro-inverters and power optimizers, but they come at a discounted price. It isn’t always appropriate to spend the extra money on micro-inverters or power optimizers. These are the best choice where partial shade or complicated roofing will have a detrimental impact on the efficiency of the solar system. If you have an uncomplicated, unshaded roof, there might be a better option for a string inverter.