Inverters are an integral part to any solar PV system, and are responsible for converting the DC electricity generated by solar panels into AC electricity that can be utilised in your home or sent to the grid. While different inverter products may have distinct features and characteristics, they must perform the DC to AC conversion to be considered an inverter.
To learn more about the different types of inverters available, and find out which is the right choice for your needs, read on.
Standard string inverters are the most commonly installed inverter type worldwide.. The DC electricity generated by solar panels is fed into this central inverter, which converts this electricity into AC electricity.
A standard string inverter by itself does not allow for battery integration. You’ll need to install a separate battery inverter. Depending on which inverter you opt for, you may be required to purchase an additional energy management system to increase your system’s efficiency.
Like their named suggests, micro inverters are much smaller in size and capacity than standard string inverters. While the latter range from 0.25 to 5kW in size for residential applications, micro inverters are usually around 250W to 500W in size.
Instead of one central inverter that converts all the DC electricity your panels collectively produce, micro inverters are usually installed on the back of every individual panel, and are only responsible for the conversion of the panel on which they are installed.
Micro inverters are significantly more expensive than standard string inverters.
Battery inverters are responsible for the charging and discharging of the electricity stored in a solar battery. Battery inverters are often installed alongside a standard string inverter, which it will AC couple or “talk” with.
Although it’s dependent on your state’s network, the rules surrounding retrofitting battery inverters can sometimes be complicated and expensive. While the act of retrofitting is simple, gaining the approvals to do so can be complex.
Retrofitting a battery inverter in the future will usually cost more than installing a hybrid inverter when initially purchasing your system.
Hybrid inverters perform the same function as standard string inverters and battery inverters. Not only can a hybrid inverter convert the DC electricity into AC electricity your home can use, it can also charge and discharge your solar battery bank.
Because hybrid inverters perform two integral function, they can be less efficient than standard string or battery inverters.
Grid-Tie inverters are simply inverters which are connected to the grid. Without getting too technical, these inverters produce a pure sine wave that is congruent with the AC waveform produced by the grid.
This allows you to send any unused, surplus solar electricity your system has generated back into the grid, which you may or may not receive a feed-in tariff for. (This depends on your electricity provider and the country you reside in.)
In the majority of cases and for most states, it’s a requirement that the inverter you install is grid-tied, whether it’s string, hybrid, or micro.
Like standard string inverters, off-grid inverters are responsible for the conversion of DC electricity generated by your system’s panels into AC electricity that can be used by the appliances in your home.
Unlike standard string inverters however, they do not have the ability to export excess solar electricity into the grid. Off-grid inverters are used in either remote areas, or where the homeowner wants to separate entirely from the grid.
Deciding to go off grid is a costly procedure and will often require total disconnection from the grid. This can be hard to undo, so you’ll need to consider the future implications (re-sale value of your home, future energy needs, etc).
You may also need to invest in a diesel generator which can be extremely costly, and become much more conscious of your energy usage to avoid your system tripping from an overload.