“Shading is the dirty little secret of the solar panel industry, and one which is often glossed over”

As I wrote last month, the starting point for my green home energy journey was an array of solar panels strapped to the roof of my house. I mentioned that my setup uses microinverters rather than a more conventional “string” inverter that takes a single input from all the solar panels wired together.

Microinverters sit on the back of a single solar panel (or are sometimes shared between two; dual microinverters can be used to reduce costs, but they also reduce the benefits). They live on the roof, attached to the panel array, whereas a string inverter would be indoors, somewhere close to your electricity meter. Microinverters send 240V AC down off the roof, whereas a string-based setup will have a nice fat cable carrying a few hundred volts of DC.

Compared to a traditional string inverter, microinverters offer two main benefits. First, they’re supposed to last longer, typically 25 years, compared to the ten-year lifespan of a string inverter. Second, they really help with shading problems.

Shading is the dirty little secret of the solar panel industry, and one which is often glossed over by the slick-suited individual trying to sell you the system in the first place. With a conventional string inverter setup, if one of your solar panels is half-shaded by a shadow from a chimney or tree, say, it reduces the output from all of the other panels by up to 50% too. That’s a huge issue unless you have a south-facing roof