Solar Panel Inverter – What Are They, and How do They Work?

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Keeping Current: Understanding the Importance of a Solar Power Inverter

If solar panels are the heart of a residential solar energy system, the solar inverter is the brains behind the operation. They may not receive as much press and attention as panels, but solar inverters are just as essential to the proper and efficient operation of a solar system.

How long does a solar panel last?

How much electricity can it produce?

A solar inverter plays a key role in answering those questions. With that in mind, let’s dive into everything you need to know to better understand what solar panel inverters do and what each type brings to the table.

What Is a Solar Inverter?

Though there are several differences when it comes to monocrystalline vs polycrystalline systems, they both work in a fundamentally similar way. When photons from the sun strike the photovoltaic panels that make up your solar energy system, they interact with the panel material and knock electrons free from their atomic structures. This causes them to flow freely and allows them to be channeled by the solar panels to create a type of electrical energy called direct current (DC). This means all of the electrons are flowing in a single direction. This setup is the basic principle behind how solar power system works and it can generate a significant amount of energy. Unfortunately, there’s one problem: your home, like virtually all of the electronic devices inside it, requires alternating current (AC).

Enter the solar panel inverter. As the name suggests, inverter solar systems invert the electrical charge generated by photovoltaic solar panels from DC to AC. In addition to being the residential energy standard, alternating current is also more efficient, more stable and more versatile. While simply converting your solar-generated electricity to alternating current is the primary job of a solar inverter, modern inverters are also capable of taking on a variety of other tasks. Before we get to that, though, let’s take a look at the different types of inverters that are available for your home.

Solar Panel Inverter Types

They may all accomplish the same basic task, but not all solar power inverters are created equal. There are several different technologies, and each of them offers its own advantages and disadvantages.

Here are the primary inverter types you should know.

String Inverter

Also sometimes referred to as a “centralized” inverter, the string inverter is the most common type of solar power inverter used in residential solar energy systems in the United States. It’s also the simplest and most cost-effective type of inverter on the market. In a string inverter system, groups of solar panels are linked together in series and connected by “strings.” Each string is then wired back into a single, centralized inverter that is typically located in a garage, a basement or mounted to the side of your home.

String inverters are simple, time-tested and easy to maintain, but they aren’t ideal for all applications. String inverter systems are only capable of producing as much electricity as their least productive panel, so your entire solar system could potentially be compromised by just one or two panels that are shaded or otherwise not producing as much energy as they should. For this reason, string inverters are best used in systems that are mounted to simple roof structures and that receive consistent, uninterrupted sunlight throughout the day.

Micro Inverter

Whereas string inverters provide a single, centralized inverter source, micro-inverters convert your solar panel energy to AC in a more decentralized manner. In a micro inverter system, each individual solar panel is fitted with its own small inverter right at the site of the panel. This configuration provides several benefits. First, because each panel has its energy inverted individually, there’s no risk of one or two panels bottlenecking the production of your entire system. Second, micro-inverters make it possible to monitor the performance of each solar panel separately.

Unfortunately, micro-inverter systems are also considerably more expensive than string inverter systems. The distributed nature of the system also makes it more difficult and costly to repair, as there are more potential points of failure and the hardware is mounted directly to the roof itself. For these reasons, micro-inverters are typically only cost-effective in specific situations. This includes systems that have solar panels facing multiple directions, homes that have complex roof shapes and systems that are at risk of shade-related bottleneck issues.

Power Optimizer

If neither of the previous solar system inverter options sounds quite right for you, there’s also a middle ground between the two. Power optimizer systems can be thought of as a hybrid option, offering some of the benefits of micro-inverter systems at a lower price point. Like micro-inverters, power optimizers are either built into each individual panel or installed on the roof next to them. However, rather than converting the electricity from each panel to AC, power optimizers “condition” the DC electricity to ensure that the total energy output is consistently maximized. The energy is then fed into a centralized inverter similar to a standard string-type system.

As with micro-inverters, this setup limits the impact of panel shading on your overall system. It also allows you to monitor the performance of each individual panel. However, while the cost is lower than a micro-inverter system, it’s still more costly than a basic string inverter system. It also presents the same maintenance and repair difficulties as micro-inverters. Because of this, a power optimizer system is a good compromise for anyone who wants the benefits of a micro-inverter system at a somewhat lower up-front cost.

It’s tempting to focus mostly on solar panels when you’re choosing a system for residential solar energy, but a quality solar inverter system is also essential to getting the most out of your system. Now that you’re armed with a better understanding of what solar inverters are and how each type works, you’re ready to make the best possible choice for your home.

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