The “capacity” of a renewables system. Size is measured in kilowatts (kW) DC (referring to direct current). A kW indicates how much power the system can produce under standard conditions, like the size of a car engine. Renewables systems are sized when they are installed to cover all or a portion of the power needs of the property. Therefore, a system designed to produce 50% of the power needs will be sized smaller than a system on the exact same property designed to produce 100%. Size may be influenced by available space at the property, orientation, landscaping, etc.