For PV systems, SAM reports the ratio of the system's annual AC electric output in Year one to it's nameplate DC capacity:

Energy Yield (kWh/kW) = Annual Energy (AC kWh) ÷ Nameplate Capacity (DC kW)

Where Annual Energy is the total annual electric generation in the first year of operation, and Nameplate Capacity is the system's DC nameplate capacity from the System Design page for the detailed photovoltaic model and the System Design page for the PVWatts model.

Note. The term "energy yield" is sometimes used to describe the total annual electrical output of a power system in kWh, and terms like "specific yield," or "yield" are used for the kWh/kW metric. In SAM, "annual energy" refers to the total annual electrical output in kWh and "energy yield" is the kWh/kW metric.