The power produced by a PV array depends on characteristics of the PV modules used and the instantaneous climatologically conditions. For most field testing, the measurable quantities are irradiance and temperature.
Power is an instantaneous value; the PV array produces so many Watts (or kilowatts) of power at a specific time depending on existing conditions. Power output will change continuously throughout the day. Energy includes a time factor and is measured in Watt-hours or kilowatt...