Solar energy doesn’t provide electricity in a format that can actually turn on your lights. This is where inverters step in. Think of them as a currency exchange for your power. You might have a roll of pound notes, but until you stop and exchange it for AUD, you can’t pay cash for Maccas on the drive home.
In less metaphorical terms, inverters convert direct current (DC) electricity, which is what a solar panel generates, to alternating current (AC) electricity, which the electrical grid uses.
Solar energy systems are only as reliable as their weakest link and inverters are a very important part of the system. There are three primary inverter setups: string inverters, inverters with power optimisers and micro inverters. In this article we will explain the benefits and disadvantages of each to help you decide what is right for you.
String inverters are your “out of the box” option when it comes to solar panel inverters and are the most commonly used. String inverters have one centralised inverter connecting a series or “string” of solar panels.
String inverters are a perfectly acceptable, cost-effective option if you don’t have any encroaching shade from nearby trees or other peripherals such as a large chimney, satellite dishes or antennas. They are also great if you have all of your solar panels facing the same direction. However, if you don’t fit these scenarios, then individual panel optimisation via a micro inverter or power optimiser will be your best option.
Micro inverters, (also known as Module-Level Power Electronics or MLPEs) work on the same principle as string inverters, but instead of having one large central inverter, they have a small unit to convert power underneath or built into each individual solar panel. This gives each panel the ability to function independent from its neighbours.
While micro inverters are more expensive than string inverters, their ability to make the most out of each panel allows you to get more power from your system overall. String inverters are still a great option for those on a budget, but if you’re after something that offers greater efficiency, flexibility and long-term ROI then micro inverters are a compelling option.
A power optimiser is not actually an inverter at all; they come as a small box that plugs into your solar panel’s DC cables and your solar panel’s AC output.
While micro-inverters completely replace the need for a string inverter, power optimisers (also an MPLE) work in conjunction with the string inverter to increase power output. Instead of converting DC power to AC power at the panel site like a micro-inverter, power optimisers condition DC power and send it to a string inverter.
Power optimisers can be inbuilt in the panels themselves, or sold and fitted on separately.
Solar panel optimisers effectively deliver many of the same advantages as micro inverters at a slightly lower cost. Both micro inverters and power optimisers provide higher system efficiency than string inverters, but for those who are after an even cheaper upfront installation cost with no sacrifice on performance then power optimisers can be an ideal option.
Ultimately, the best inverter setup for you depends on your roof shape and size, nearby trees, how much energy you need, and your budget. Micro inverters and power optimiser systems have very similar efficiencies, are good for monitoring individual panel performance, and can help maximise energy production on slightly shaded or complicated roofs. Independent variables such as warranties and climate should also be taken into account when considering a purchase.
It’s important to keep in mind that micro inverters and optimisers certainly aren’t the be all and end all – if you’re looking for the most economic option and have a north-facing roof with little shade, string inverters are the way to go.
To find out what set-up will work for you and your home, we recommend speaking with an installer that will help you choose the best option. You can receive up to 3 FREE quotes by completing this quick quiz.