We’ve come a long way from the first solar cells developed more than a century ago, but the technology still has tons of room to improve.
The first solar cells developed by Charles Fritts didn’t put out much power and only had an energy conversion rate of 1 to 2 percent. Today’s solar panels regularly approach 20 percent, and are constantly improving with better efficiency, lower installation costs, and increased subsidy assistance from the government.
More people are hopping on the residential solar bandwagon, not only as a way to save money on their constantly rising energy bills but to work toward a greener future, too. The home solar revolution is also picking up speed, thanks to the Inflation Reduction Act.
The multi-billion program earmarks money for addressing climate change, while extending a 30% tax break for new residential solar installations through 2032, with slight decreases through 2034. For most homeowners, the tax break is worth about $7,500 on an average rooftop installation.
Although solar panels are the first things most people see when they spot an installation, they can’t create usable electricity on their own. There are several critical pieces that must work together for the solar panel installation to work effectively, including the solar inverter.
Although there are plenty of technical ways to describe what a solar inverter does, the concept is pretty simple; it takes DC power produced by the solar panels and turns it into AC power for your home. Most homes use AC electricity at 60 Hz, so the power produced by the panels is largely useless until it’s been converted from DC to AC.
Your solar inverter is also connected to the larger electrical grid, using what’s called a grid-tie inverter. When your PV system generates too much solar electricity, the extra power is diverted to the larger grid, but the process also works in the opposite direction, too. Let’s say it’s an especially cloudy day and there isn’t enough solar power to keep everything running. The grid connection ensures your home is always powered and there are no service interruptions.
When you decide to install a solar power system, you’ll have several inverter options to pick from. Depending on the layout of your panels, the amount of shade nearby, and how much money you’re willing to pony up for your system, some types of inverters will make more sense than others.
This inverter type collects all the power generated across the solar panel array. It’s the standard solar set-up choice and is generally the most cost-effective option for people who are trying to keep the cost of their system installation in check.
These inverters work as part of a series circuit and only produce as much power as the lowest performing panel in your array. For example, if you have four panels installed on your roof and three are operating at 90%, but the fourth is blocked by shade and performing at only 50%, all four of your panels will be capped at 50%. The same result could occur if a panel is damaged or starts to lose its efficiency due to old age.
String inverters make sense when all the solar panels are facing in the same direction and there isn’t much shading to block them from producing electricity. If you can ensure these two conditions are met consistently, a string inverter could be a good, low-cost energy production option.
Keep in mind, though, that string inverters carry a few limitations. Because all the panels are connected to a single inverter, if one panel is underperforming, the whole array suffers. Additionally, if problems do arise, it’s a lot harder to figure out which panel is damaged because they’re all doing the same thing. This could cause delays, stifle power production, and prevent you from getting the most out of your installation.
It’s also worth noting that if you decide to add solar modules, you’ll have to add another complete string inverter system, too.
True to their name, micro inverters cover a much smaller portion of a residential solar array than string inverters do, by connecting to each individual solar panel.
Micro inverters are more expensive than string inverters but offer several benefits you won’t find in other options. First of all, by connecting to individual panels, micro inverters can get optimal production from each panel, rather than having to cap power to match the lowest production. That means your system can produce more electricity overall by taking advantage of every bit of its efficiency.
Despite costing more than other inverter options, solar micro inverters come with a variety of benefits that make them a good choice for homeowners. Not only can they outproduce a string inverter system, but the individual inverters can also highlight potential problems with the panels themselves.
Unlike string inverters which typically rely on panels facing in one direction, micro inverters put you in control, allowing you to put panels where they’ll perform the best, even if they aren’t facing the same direction. They can also mitigate shading problems and other hindrances that could hamper overall production with a standard string inverter setup.
As you add more panels to your installation, you will need to add more micro inverters, but you have more flexibility in where your panels are installed. This allows you to avoid shaded areas, take advantage of the sun in any position, and even take advantage of different seasons.
Optimizers are unique hybrid inverters that cost about the same as a microinverter but allow solar panels to produce electricity at a higher power, rather than working with a reduced current load. They cost about the same as a micro inverter system but have the ability to help you get more out of aging or impacted rooftop solar installations.
If the solar installation is older or panels are impacted by shading or other external factors that could limit productivity, optimizers can give the system a much-needed power boost. They also have the unique ability to help older panels perform better as they age, helping them maintain efficiency. And much like a micro inverter, optimizers can monitor individual panels in the system, making it easier to identify and correct problems earlier.
Unfortunately, despite their ability to increase power in panels, optimizers cannot convert direct current (DC) electricity into alternating current (AC) power. That means that you’re still going to need string inverters to handle the conversion process. On the bright side, unlike a micro inverter, if an optimizer breaks, you don’t lose power. It simply returns to its original efficiency, and even then, you’d notice an issue because of the weaker performance.
Where would an optimizer work best? Typically, you’ll find optimizers in systems where the panels aren’t working as efficiently as they could be, either due to age, shading, or seasonality.
In a world where everything thinks they’re the next Bob Vila, keep in mind you’re dealing with potentially high voltage electricity. No matter what type of inverter you select for your next solar installation, be sure to find a licensed, professional installer to perform the work for you.
From solar modules and inverters to PV wire and solar inverter cables, an installer will likely have access to high-quality materials designed to make the most of your investment. They can also do the job quickly and safely, leaving you with a clean installation that lets you take full advantage of the sun’s energy and lower electricity bills.
If you’re interested in learning more about solar installations, tax credits, and to better understand what programs are available to you, visit the U.S. Department of Energy’s website.
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