australian-rooftop-solar-excess-capacity

Approximately 80–90% of Australian rooftop solar systems, with a midpoint estimate of 85%, possess an average daily surplus capacity of at least 6.5 kWh Verified Answer #1. When considering all Australian homes rather than just those with existing solar installations, this share represents roughly 30–35% of all residences Verified Answer #1. Excess capacity is defined as the average daily solar generation minus the amount of energy consumed on-site Verified Answer #1.

System Size and Generation Factors

The daily surplus of a rooftop photovoltaic (PV) system depends on the daily generation per installed kilowatt and the percentage of that generation that is exported Verified Answer #1. Australian systems typically generate between 4.0 and 4.5 kWh per installed kilowatt each day Verified Answer #1. For households without batteries, a conservative estimate assumes that approximately 60% of this generated energy is exported Verified Answer #1.

Based on these generation and export assumptions, the expected daily surplus per installed kilowatt ranges from 2.4 to 2.7 kWh Verified Answer #1. To achieve a daily surplus of 6.5 kWh, a system generally needs to be sized between 2.4 kW and 2.7 kW Verified Answer #1. Even under stricter calculation assumptions, the required size threshold for this level of excess capacity remains around 3 kW Verified Answer #1.