Let’s dive into solar inverters – the rather bland looking electronics that unlock your solar array’s superpower.
If you think about solar panels as the body of your solar energy system, then you can imagine the inverter is its brain. Panels and inverters work together to ensure your system is generating the maximum amount of electricity it can.
We are all familiar with solar panels, as they are the most visible part of a solar energy system. However, the inverter is an equally important component to know about, as it allows energy captured by your panels from the sun to be converted into usable electricity for your home.
ReVision Energy installs inverters from SolarEdge and Enphase, two long-standing companies in the solar industry that have set the standard for innovative, high quality inverter technology. The inverters we use for our projects meet rigorous safety and efficiency standards, and allow us to design, install, and monitor our customers’ systems for continuous, maximum output.
Other than solar panels, the other major component of a solar electric installation is the solar inverter. Solar energy doesn’t create electricity in a form that can power your refrigerator or charge your computer. Inverters transform the power generated by solar panels into a form of electricity you can actually use in your home.
An inverter is a piece of electrical equipment that generates grid-compliant alternating current (AC) electricity from the raw direct current (DC) electricity produced by your solar panels. It is responsible for allowing the electricity from the solar modules to flow and ensures that power is clean (from an electrical perspective) and able to interact with the grid. A solar project can have on or several inverters, depending on the design, as well as power optimizers that work with inverters (more on that below).
The graphic above illustrates how the flow of electricity generated by your panels moves through the inverter technology and into your home.
A solar project can have multiple inverters, depending on the size of the system. They are very important pieces of equipment in a rooftop or ground mount solar system, which means ReVision Energy has spent a lot of time and energy deciding on which types of inverters to install for our solar customers.
There are three options available: string inverters, microinverters, and power optimizers.
There are several differences between the three types of inverters, and each has its own set of pros and cons. Let's dive into the details of string inverters, microinverters, and power optimizers, and how they work in a solar power system.
String inverters, the standard inverter style, have one centralized system. This design works well when solar panel outputs are closely matched, and to this day they're our preferred choice for exterior ground-mounted arrays in open fields with full solar access. They tend to perform best in situations with full sunlight exposure. Sort of like old school Christmas lights (when a single bulb went out, the entire set of lights stopped working), if a single solar panel is shaded in an array with a string inverter system, it significantly reduces the output of the entire string.
Modern string inverters actually deal with this issue much better than older models thanks to a technology that includes multiple Maximum Power Point Tracking (MPPT) inputs per inverter.
String inverters are standard in the industry, and they’re the least expensive.
Microinverters are small units built into each solar panel. Instead of relying on an entire string, each solar panel is essentially its own independent inverter system, hence the 'micro' name.
The motivation for building this type of inverter technology was to solve for a situation when the array experiences mixed lighting (for example, during the day a large tree casts a shadow across of your solar panels). Microinverters allow for the entire array to be more consistent and continue to generate energy while one or several inverters are not working.
Unfortunately, the promise of microinverters was also severely impacted by equipment failures in the early generations. Sort of obviously - with a string inverter, though it may seem like "hmm you have one inverter if that goes down your whole system turns off" - it actually proves that putting a single piece of equipment in an accessible location protected from extreme temperatures is far easier on the equipment than having them be installed on the bottom-side of solar panels, where temperatures can exceed 140 degrees Fahrenheit, as microinverters are.
Microinverters, such as the Enphase models we install, have become more reliable and efficient over time, making them a great option for many homeowners. Although more equipment on your roof can mean more potential points of failure, microinverters offer advantages in flexibility and system performance.
Power optimizers are between string inverters and micro-inverters both in how they function and in price. They are essentially string inverters with individual panel-level electronics.
A Power Optimizer system allows for panel-level monitoring and power regulation as with a microinverter, but the transition of energy from DC to AC still happens at a central SolarEdge string inverter. This is accomplished with individual power optimizers that are attached to each panel via the racking, as seen in the photo.
Around 2011, new fire codes were adopted across Maine, New Hampshire, and Massachusetts that created a 'rapid shutdown' requirement, meaning that a solar array that is turned off during a fire event needs to discharge power within 10 seconds. String inverters, by design, took longer than 10 seconds to shut down and thus were essentially disqualified from the North American market. The module-level electronics in SolarEdge overcomes this.
The system has all the same advantages of a string inverter (overall more efficient and the 'guts' of the system protected by being in an electronics-friendly environment) with some of the same advantages of microinverters - the optimizers attach to each panel, and each panel can communicate to the whole for data monitoring purposes as well as fire code compliance. Unlike microinverters, there is less 'stuff to break' with a power optimizer design.
We offer both SolarEdge Inverters with Power Optimizers and Enphase Microinverters. Our team will help you pick the best option based on your home’s specific needs.
SolarEdge Power Optimizers are excellent for larger systems and work well in scenarios where shading might reduce performance. They strike a good balance between cost and efficiency.
Enphase Microinverters are a great option as well, especially on complicated roof shapes that feature multiple smaller subarrays. They make for easy expansions to system size, and so are ideal for homeowners thinking about making upgrades in the future.
The installation site and customer goals drive our inverter design choices. Many solar contractors install exclusively SolarEdge or Enphase, but we offer both because it allows us to match the best technology to the unique needs of each project.
(A photo of solar array with an inverter and power optimizers on the bottom of the panels)
Both SolarEdge and Enphase systems come with responsive temperature and safety features, which are important for the efficiency and longevity of any solar equipment (as well as peace-of-mind of the homeowner).
SolarEdge inverters come with a 12-year warranty, and their optimizers come with a 25-year warranty. Enphase microinverters come with a 15-year warranty. Both inverters allow you to extend the warranty to 25 years at a low cost. These warranties are on the higher end of industry standards, which generally fall between 5 and 12 years on average.
Our expert Solar Design team will work with you to determine the best inverter for you home energy project. Reach out to our team today to start your solar journey!
