What is the DC/AC ratio and what is clipping?

The DC/AC ratio (also known as the inverter loading ratio) is the quotient of the installed module power (kWp, DC side) and the rated power of the inverters (kW, AC side). In industry, systems are typically designed with a value between 1.1 and 1.3, meaning that more modules are deliberately installed than the inverter can pass through at maximum. The reason is that modules only deliver their rated power under ideal conditions; for most of the year they generate below it, so oversizing increases the yield in the morning and afternoon hours. Clipping is the energy that the inverter cuts off in the sunniest hours, because the DC-side power exceeds the AC capacity. In a well-sized system this is a small share of annual generation, and the gain more than covers it. At an industrial site with a reverse-power limit, however, a second source of loss appears alongside clipping: the energy the system cannot deliver because the site is not consuming at that moment. With battery storage both losses can be utilized, so designing the DC/AC ratio together with the storage gives a different optimum.