We covered inverters in a previous post, but I’ll run over it quickly first, so this post can stand on its own.
Solar panel inverters are necessary to change stored current from the solar panels from Direct Current (DC) to Alternating Current (AC). This is necessary because the solar power system generates DC current, and our appliances need AC.
Our appliances don’t actually use AC current, they convert it back again to DC internally. The nature of current PV technology means the way electricity is channeled in a solar cell, comes out as DC.
While this is the most efficient way of powering electrical items, it isn’t the most efficient way to transport electricity. The nature of DC current means it can lose up to 25 percent of the electricity in transit, which is why we use AC.
The AC sine wave is much more efficient at traveling long distances, which it would over the grid. A solar panel inverter sits between the batteries of a solar panel array and the grid or mains. It’s job is to control power flow back and forth into the system, and change DC power into AC, ready for use.
In a traditional setup, there is a single inverter to control the entire system. This is an efficient way of doing it, but presents a single point of failure for the system. A solar power array is a fairly low-maintenance piece of kit, but if any trouble occurs, it’s almost always the inverter at fault.
A micro inverter is a smaller version that sits behind each solar panel. Each panel has its own micro inverter pumping AC current directly into the batteries, or straight to the house. While there is more equipment involved, it’s a much more efficient way of working.
We mentioned that DC is far from lossless, and can lose quite a bit of current in transit. We know AC can travel further while losing less, so it makes sense to have AC moving around the system. That way we get to use more of the power we generate. So by using micro inverters instead of standard solar panel inverters, we save a potential 25 percent of the energy we generate.
Add to that the physical benefits and you have quite a compelling case. Micro inverters are of course smaller, and they cost less individually than a standard inverter. If one fails, it’s cheaper to repair or replace. It also doesn’t bring the whole system down, just the panel it’s connected to. So in the event of hardware failure, you’re still generating power.
Micro inverters also add scalability to a solar energy project. If you find you need more power at a later date, it’s simply a matter of bolting on another solar panel and micro inverter and connecting them up. It’s a much simpler exercise than the traditional setup.
Both solar panel inverters and their micro cousins have distinct advantages. However, in the pursuit of efficiency and convenience, micro inverters win every time.