An inverter is a device that converts the electricity generated by your solar panels from direct current (DC) into usable alternating current (AC). They tend to be sited in the loft and are typically no larger than a microwave.
Depending on the model, some inverters come with an online platform so you can monitor the electric output from your computer, whereas others come as a combi-PV inverter and battery.
Types of inverter
There are two main types of solar inverter: string inverters and micro-inverters.
String inverters are the most common type of inverter, as they are the cheapest and easiest to install. All the solar panels feed into one string inverter, so your whole installation behaves like one giant panel. This can cause issues for houses prone to shading, because if one panel has a reduced generation for some reason, the other panels suffer the same loss of electric output.
These inverters have a higher upfront cost (£100-£150 each) than string inverters, but they’re more profitable in the long run. Microinverters are connected to individual solar panels, so you’ll need as many inverters as there are solar panels. The main benefit to having this kind of setup is that the solar panels operate independently from one another; if one solar panel is shaded from a chimney or nearby tree, the other panels won’t be affected like they would with a string inverter.
Another benefit is since you can see the generation from each solar panel, you can adjust the underperforming ones accordingly, by repairing them or moving them to a less shaded area.
Micro-inverters have a longer lifespan than string inverters, as they only need to convert the DC generated from a single solar panel (roughly 250 watts). String inverters must convert the total electricity from all the solar panels, and this high wattage puts a lot of strain on the transformer.
You’ll have to replace your string inverter at least once during the lifetime of your solar array, whereas microinverters often come with a 25-year warranty, and commonly last as long as your solar panels.
Feed-in Tariff (FiT)
It’s said that micro-inverters can increase electric output by around 20%. As the payments from the Feed-in Tariff are relative to the amount of electricity generated, fitting your solar panels with micro-inverters should significantly increase your Feed-in Tariff income.