Inverters are an essential component of any solar panel system. They’re responsible for converting direct current energy (DC) generated at your solar panels into usable alternating current (AC) electricity for your home’s appliances. When it comes to choosing an inverter solution for your solar panel system, there are a few options to consider. In this article, we’ll go over one of the more popular types of inverter technologies: microinverters.
What are microinverters and how do they work?
As opposed to a solar energy system that has one centralized string inverter, microinverters are smaller inverters installed right at the panel site. Most solar panel systems employing a microinverter solution use one microinverter for every individual panel.
Because each microinverter operates at the panel site independently of the others in the system, microinverters are classified as module-level power electronics (MLPE). MLPEs are the best option for complicated installations or those that experience marginal shading. With traditional string inverter technology, panels can only produce electricity at the level of the lowest-performing panel on the same string. This isn’t a problem with microinverters – because panels have their own inverter, solar panels will continue performing efficiently even if one panel in the system isn’t producing electricity.
The size of each microinverter is dependent on the size of the panel and the amount of electricity it’s capable of producing (as determined by your geography, the tilt, direction it’s facing, and more). If your solar panel produces more electricity than its microinverter is able to convert at a given moment, “clipping” occurs, resulting in power losses.
When to use microinverters
There are many reasons to consider installing microinverters. For one, they allow for individual panel performance monitoring. With microinverters, you can compare how each panel is performing on its own, rather than solely evaluating the performance of the system alone. This can mean quicker servicing of equipment, as it’s easier to identify if a particular panel or microinverter is failing.
Microinverters are also a good solution for more complicated installations that have panels facing different directions or are tilted at varying angles. If you have some panels facing east and others facing south, using microinverters on each panel will allow them to perform to their maximum ability when sunlight hits them, as they will be not impacted by the production issues other panels in the system might experience.
Microinverters are typically more expensive than other inverter options. The additional upfront cost can be well worth it for the added monitoring and production benefits. If you have an easy installation on a single roof plane facing south with no shade, a lower-cost string inverter system can be an effective solution.
Microinverters vs. string inverters and power optimizers
The three most common inverter options are microinverters, string inverters, and power optimizers. Here’s how microinverters compare to the other two popular inverter types:
The biggest difference between string and microinverters is that when using a string inverter to wire your panels, depending on the size of your solar system, you only need to use one or two string inverters (usually just referred to as “strings”). This makes troubleshooting easier if your system fails, as all 6-12 panels that the inverter supports are wired to just one destination. Given the minimal wiring requirements, string inverters are also cheaper to install and maintain than microinverters. That being said, the simplified wiring scheme can also make it more expensive to expand your solar system in the future, and also means that underperforming solar panels will affect the whole circuit, rather than just its individual output.
Power optimizers, unlike micro and string inverters, don’t convert direct currents to alternate currents immediately, instead they “condition” it and send it to a centralized inverter. These module-level power electronics, or MLPEs, are very similar to microinverters because they can monitor individual solar panel performance, and allow for flexibility in building a solar system on a marginally shaded roof.
Dive into our comparison of microinverters and power optimizers to learn more.
How to evaluate microinverters
When comparing your microinverter options, there are a few main factors to keep in mind:
Just like solar panels, microinverters have varying efficiencies. An inverter’s efficiency is a measure of how much energy is lost in the form of heat during the conversion from DC to AC electricity. Higher efficiency microinverters lead to higher overall system efficiencies and more solar electricity production.
Microinverters come in varying sizes each designed to handle different voltages of electricity. Larger microinverters will often be more expensive; however, you don’t want to install a microinverter that’s too small for the associated panel’s energy output, as that will result in too much clipping. Manufacturers of microinverters often list guidelines as to the maximum DC wattage a solar panel should have when connected to their products.
Most microinverter options available on the market today come with a 25-year warranty, which will protect you against potential manufacturing defects or undue degradation. However, even two different microinverter manufacturers that offer the same warranty term may offer different levels of coverage as part of the warranty. It’s important to read and compare warranty agreements when choosing solar equipment.
Although they are not typically the most expensive component of a solar panel installation, it’s still important to weigh the price you’ll pay for microinverters. Higher efficiency microinverters with longer warranties often come with higher price tags but can be worth it depending on the setup of your solar panel system and your preferences.
Rapid Shutdown Requirements
When a rapid shutdown is in place, microinverters can shut down automatically in compliance. Each module has software programmed in it to shut down in sync with these rapid shut downs so no extra hardware is needed.
Many manufacturers offer microinverter products; here are a few of the more well-known names:
Enphase, headquartered in California, is the market leader in microinverter technologies. Their IQ series is a popular option for residential solar panel installations. In addition to manufacturing standalone microinverters, the company partners with multiple solar panel manufacturers to offer AC modules. They also manufacture energy storage and monitoring systems to pair with their microinverter products.
SunPower, a leader in high-efficiency solar panel modules, purchased the microinverter company SolarBridge in 2014. However, in 2018 the company sold its microinverter business to Enphase. SunPower’s AC modules, used in their Equinox systems, now employ microinverter technology built and designed by Enphase.
APSystems was founded in California in 2010. Unlike many microinverter solutions, their microinverters are designed to connect to more than one panel. In fact, one APSystems microinverter can connect with up to four panels.
Compare all your inverter options on the EnergySage marketplace
Solar panel systems last for more than 25 years, so it’s important to make a confident decision when it comes to choosing your equipment. On the EnergySage Solar Marketplace, you can receive up to seven solar quotes to compare online. Local installers will provide custom quotes and propose an inverter solution given your unique situation. These quotes will include information about your inverter options, including but not limited to warranty, type of inverter, manufacturer, and more.