Simply put a micro inverter converts each individual solar panel's output from DC to AC at roof level enabling each panel to operate independently of the other panels. This is in direct contrast to the more usual (at least in the UK) string based system where strings of panels are joined together prior to travelling to the inverter to be converted from DC to AC. Micro Inverter based systems are very popular in the US and are now starting to get significant traction in the UK and Europe.
There is no one size fits all solution here, it comes down to a combination of personal preference and whether a string based or micro inverter based system would work best for your particular installation as both types offer pros and cons.
String based inverters convert the energy from a string of solar panels, which produce electricity as a direct current (DC) to AC which can be used in the home. The inverter is generally placed away from the solar panels and requires a run of DC cable from the panel to the inverter. DC is much more dangerous than AC and requires careful planning and installation to ensure there is no risk of fire or electrocution and meticulous labelling is required to ensure the safety of people working close to the system both during install and in the future. Also there is voltage loss associated with long cable runs of DC so careful selection of cabling is required for an optimal result.
The big advantage of a string based system is that one inverter can look after a large amount of panels and is generally put in a location that is easy to repair. This means that there are less points of potential failure compared with a micro inverter based system and if there is a failure, access to the roof is rarely required. The big downside is: if there is a problem with the inverter the whole system will go down and will not produce electricity until it can be repaired.
Now lets consider a system based around micro inverters. In this system each panel has a dedicated micro inverter where sunlight is converted to AC at roof level for use in the home. There are several advantages to this approach.
Firstly, unlike a string based system, each panel panel operates completely independently. Thus if a panels performance is impaired by a technical issue, dirt or shading, then the performance of of the system is only marginally affected, as the rest of the panels are still performing as normal. In a string based system performance is always reduced to the level of the poorest performing panel.
Its possible to mitigate this risk by installing products called optimisers on each panel which has the ability of switching off panels that are affected by technical issues, shading or dirt, but it must be remembered that all of the extra optimisers can act as additional points of system failure and will inevitably add to the initial cost of the system
Microinverter based systems are often safer as conversion to AC is handled at roof level reducing both fire risk and worker safety.
The key disadvantage of systems designed around micro inverters, is that you are introducing more points of potential failure, due to the increased number of inverters. However it should be remembered though that the global failure rate of Enphase micro inverters currently stands at less than 0.2% and that they also come with a 25 year warranty. Importantly: if there is a problem (monitored on both your smartphone app and on installers portal) only that panel will be affected until a repair can be organised.
If you want to discuss whether solar could help you save money and reduce your carbon footprint. Why not book a preliminary call with one of our experts today.
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