Several factors affect solar energy production. These include solar irradiation (energy) levels at your location, your solar panel orientation, and your solar system size.
Understanding how much energy solar panels will generate is an important step in designing any solar installation or a solar and battery installation. At LuvSolar we’ll always provide theses estimates as part of the initial system design process
Solar Installation in Australia
Solar energy production depends on how much sunlight is available in a location. This varies day to day, but is quite consistent from year to year. The map below shows the average solar irradiation measured in kilowatt-hours per square meter per day (kWh/m²/day) at locations around Australia taken from satellite data (credit SolarGIS).
These values indicate the amount of solar energy available for per square meter that is available for conversion into electricity. Areas with higher irradiation receive more sunlight, resulting in greater energy production from the same solar panel system. Locations further north and those with consistently clear skies will always receive more solar irradiation on average.
- A solar installation in Melbourne will receive: ~4.1 kWh/m²/day
- A solar installation in Newcastle will receive: ~4.2 kWh/m²/day
- A solar installation in Byron Bay will receive: ~4.4 kWh/m²/day
Standard 6.6kW Solar System and Inverter Limitations
A 6.6kW solar panel system is the standard residential setup in Australia. This size is commonly paired with a 5kW inverter because regulations typically allow a 5kW inverter to be connected to a single-phase power supply without requiring additional approvals. The 6.6kW of panels maximizes the system’s output while staying within the inverter’s capacity, as inverters can operate efficiently even when panel capacity slightly exceeds their rating. Read more about how much solar you can install on your roof here.
Expected Energy Output from a 6.6kW System
Assuming a 20 degree roof pitch with all panels facing north, the expected daily energy production of a 6.6kW solar system varies by location as follows:
- Melbourne: 6.6 kW ≈ 24 kWh/day
- Newcastle: 6.6 kW ≈ 27 kWh/day
- Byron Bay: 6.6 kW ≈ 29 kWh/day
These figures represent average daily production, though actual output will vary seasonally and due to weather conditions.
Panel Orientation and Angle
To maximize solar energy production, panels should face north in Australia and be tilted at an angle close to the latitude of the installation site. However, east- and west-facing panels can still produce substantial energy, typically around 85-90% of the output of north-facing panels. A steeper tilt will improve winter performance, while a flatter tilt is more beneficial for summer months.
How Solar Panels Work on Cloudy Days
Solar panels still generate electricity on cloudy days, though at reduced efficiency. This is because Solar irradiation consists of two components:
- Beam Irradiance: Direct sunlight that travels in a straight path from the sun (think sunbeams).
- Diffuse Irradiance: Scattered sunlight due to clouds, dust, or atmospheric conditions.
On a fully overcast day, diffuse irradiance dominates, and solar panels typically produce around 30% of their peak output. Even on cloudy days, a solar system can still contribute meaningful energy, particularly in bright overcast conditions where thin cloud cover can scatter light effectively.
A well-designed 6.6kW solar system in Australia can generate between between 25-30 kWh per day, depending on location and conditions. While peak performance occurs in full sunlight, panels continue producing energy even on cloudy days due to diffuse irradiance. Understanding local irradiation levels, system size constraints, and panel orientation helps optimize energy generation, making solar a reliable and cost-effective solution for homeowners and businesses.
