Electric charge (conventionally denoted Q) is a property of matter that describes the force experienced (and exerted) in the presence of other electrically charged matter.
Most fundamentally, energy is the ability of an object or a system to perform work, and we most often observe energy indirectly by the work that is performed. The motion of an object through space, the heating of a substance and the illumination of a room are all examples of work being done and represent different forms of energy.
A photovoltaic ("PV") array describes the part of a PV system that converts solar energy into electrical energy. While there are other critically important components of the complete photovoltaic system - most significantly the inverter in all grid-connected systems - the array comprises all of the electrically-connected photovoltaic material.
