Posted on: 3 December 2017Share
Installing a solar grid on the roof of your home, even if it may initially be expensive, can be a major cost savings over time since it will radically reduce your monthly energy bill. One of the considerations you and your solar power installation contractor will have to make is whether to use module-level power electronics (such as a microinverter) or a string inverter for your solar grid. The purpose of an inverter is to convert the DC power produced by your solar panels into AC power that can be used to power your home; microinverters are installed at each panel and perform the conversion there, whereas string inverters connect all panels onto a wire that transmits DC power to a central inverter to be converted. Microinverters offer a number of benefits over a string inverter and cost only slightly more. Here's why microinverters are the preferred choice for your residential solar grid.
Solar Panels Installed With Microinverters Are More Scalable
If you're installing a small solar power system, such as if you're wanting to see how it performs for your energy needs before investing more money into your solar power setup, you'll be glad to know that solar panels installed with microinverters are more scalable than those installed using a string converter. The reason for this is that string converters are rated for certain solar panel layouts (for example, two rows of four panels each or one row of nine panels) and all solar panels connected to the string inverter must be the same orientation and the same model. This makes it very difficult to add more solar panels in the future without radically changing your solar panel setup and purchasing a new string inverter. On the other hand, microinverters can handle solar panels installed in different orientations all on the same line and additionally can have multiple models of solar panels producing power at once with no issues. This makes it much easier to start small and then scale up your solar power usage over time by adding more microinverters and more solar panels.
Microinverters Avoid The Single Point Of Failure Of A String Inverter
All of the solar panels on a string inverter system feed their DC power into the main inverter located on the outside of your house. If even one of the panels goes down and stops producing power, all other panels on the string inverter will also stop providing power. In addition, performance for each panel is capped at the worst-performing panel on your roof. If one of your panels has a manufacturing defect or is dusty and is only producing power at half of its capacity, all other panels on your roof will be limited to producing half of their potential power even though they may be functioning perfectly. This is the main issue with string inverters, as shade from a chimney or tree during certain hours of the day cast over even one of the panels can significantly reduce the power output of your whole solar grid.
Microinverters are not linked in this manner; each panel will produce its maximum power allotment and is not affected by the status of the other solar panels. If one is covered by shade and only producing a fraction of the power it should be, only power output from that panel will be affected and not your entire solar grid.
Automated Monitoring Lets You Spot Problems Sooner
Microinverters are able to report the status of the attached solar panel to a central monitoring system; this allows you to see if any of your solar panels are not producing power or are regularly operating under maximum output due to dust or debris. You're notified of any panels that have difficulties right away by the monitoring system; with a string inverter, a solar panel failing will take down the whole grid and it can be a maintenance nightmare trying to figure out which panel has stopped producing power.
Ultimately, Enphase microinverters are a better choice than string inverters for your solar power grid, even though the cost will be slightly more than a system using a string inverter. They are more robust and allow you to detect problems earlier and will do a better job maximizing the power output of your solar grid if it is affected by faulty panels, shade or debris.