Are microinverters a good idea for solar power systems

A few clients have been asking us lately about micro inverters and so I thought it would be worthwhile to give my views on this subject.

For those of you who don’t know what I am on about a typical solar power system has the solar panels on the roof that produce DC electricity. These panels are wired in long strings and this DC power travels down off the roof to a single inverter that converts the DC solar electricity to AC grid compatible power.

With micro-inverters the idea is that each panel has its own mini inverter that converts each panels power to AC electricity.

The upside of this is that losses are slightly less running power in Ac and also one panel in a string being shaded will not affect at all the output from the other panels in the system.

So is it a good idea?

My view is that it is not because in my experience panels are very reliable and almost all problems with solar power systems are caused by failures with inverters not with the panels themselves.

The idea of having 20 small micro inverters in each system seems like a maintenance nightmare from my perspective and significantly increases the risk of failures in the system.

Over the years in the industry it seems that each year there is a new brand of inverter that supposedly is newer and better but usually within six months failures have meant that they are barely sold any more and the companies that sold them go out of business. This is why I really only trust SMA inverters and am distrustful of the quality of the new micro inverters that are coming out.

I still have an open mind and if SMA made a micro inverter solution I would probably look at it in the future because I would be more likely to trust the quality of the inverters. But for now I don’t think it is a safe thing to get into selling systems with micro-inverters.