With a standard solar system, because the panels are connected in series the output of each string of panels is restricted to the level of the worst-performing panel.
This can cause reduced output if there is shade, dirt or leaves on a panel, or if one of the panels is underperforming.
With a SolarEdge system, there is a small DC Optimiser that is connected to each panel that helps optimise the performance of each panel. This can help increase your system’s output and hence the savings on your power bills.