The Case for Microinverters

 


When choosing the right solar system for your home, there are many factors you have to take into consideration. Among the most important can be the technology you choose. This isn’t like many of our technological purchases, like buying the latest smartphone that you can upgrade in a year or two. This equipment is going to be part of your property for the next 25 or more years, so needless to say it’s worth some research and careful consideration.

Luckily, you have entered the solar marketplace at a great time. The technology is more advanced and less expensive than ever before, so you are in a prime position to minimize your payback time and save thousands on your electric bills. Traditionally, you will be looking at options for solar modules, racking (how the panels will be attached to your roof), and inverters, which convert the direct current (DC) produced by your panels to the alternating current (AC) required by your home’s appliances. The most common inverter technology has been string inverters, in which your modules would be “strung” together and fed into a single inverter device.  However, microinverters and power optimizers are increasing in popularity and becoming more affordable. Microinverters and power optimizers are attached to the back of each individual panel. To learn more about the differences between these three options, check out this article from Energy Sage. We at Brighten Solar often recommend microinverters to our residential clients, but we are surprised to learn that many people aren’t aware of this relatively new technology. Could microinverters be the right fit for you? Here’s why we think so.*

 

1. Efficiency Optimization

Unless your roof faces due South and you live in an area without trees or other buildings, chances are you are going to get some shading from time to time. Further, if your panels get too hot, it lowers their output efficiency.

In the case of a string inverter system, when one panel experiences shade or a disruption to its efficiency, it will limit the performance of the entire array. With microinverters, power is optimized at the panel level, so each panel will independently produce at their best capability.

Solar I-V curve: Available sets of current (I) and voltage (V) combinations for a solar module. As the current’s intensity decreases, only a certain level of voltage can be reached. Instead of having just one curve for the entire system with one maximum power point (in the case of string inverters, the lowest point), microinverters allow each panel to perform at its own maximum power point.

 

2. Scalability and Design

When sizing your solar system, the goal is to zero your net energy usage for the year. However, over a 25+ year period, your power consumption is bound to change. Are you planning on having children, or do you have children who will be hitting teenhood soon? (We hear teens use a lot of power.)  Are you considering an electric vehicle, a pool or hot tub, or another high-power device? It can be challenging to think that far ahead. With microinverters, it is extremely easy to add panels to your solar system.

Also, since your panels don’t all need to be arranged in a line, microinverter systems allow for more flexibility in design options.This is especially useful for homes with irregular roofs or for customers interested in a more aesthetic design.

 

3. Troubleshooting and Performance

When your solar system is up and running, you can monitor the system performance from a mobile app. What if you notice a sudden drop in your system’s output? With a string-inverter system, it is more challenging to pinpoint the exact source of the issue, because as mentioned earlier, the whole system’s performance is limited by the array’s weakest producing panel- plus there is a long string of connections that will need to be checked. Microinverters make troubleshooting much simpler, as the performance is being monitored for each individual panel. 

You also don’t have to worry about a single point of failure bringing the whole system’s performance to a halt. If for some reason a panel or its microinverter malfunction, the rest of the array continues to produce as usual.

 

4. Safety

The direct current produced by solar panels comes at a much higher voltage than the converted alternating current we use in our homes. Since the current is being converted on the spot with microinverters, you don’t have to worry about high-voltage direct current flowing on your roof.

If there is a fire or emergency and the AC circuit is disrupted, the DC must also be shut down to protect first responders and the building itself. Regulators have enacted a “Rapid Shutdown” requirement, which has been implemented in different ways by manufacturers for string inverters. Microinverters already have a rapid shutdown feature built into every unit that performs in just 100 milliseconds! This is ten times faster than the required standard.

 

3. Warranty

Warranties for microinverters are usually 25 years, where string inverters usually have a 10-12 year warranty. Most panels come with a 25 year warranty so it’s certainly convenient to have all your technology warrantied for the same period of time.

 

Microinverters may be petite, but they’re putting up a strong fight to rise to the top of the residential solar market. We always recommend a solar shopper to do their homework and be sure to weigh out the costs and benefits of each option to find the right fit for their needs. This is why we always help our customers compare their options to customize the perfect solar system for them.

*Remember, Brighten Solar Co. is not affiliated with any manufacturer. We make recommendations from experience, research, and the best interests of our clients, not sponsorship!