Photovoltaic generation calculator
About the tool
The Photovoltaic (PV) Generation Calculator is a free BRANZ tool that helps you estimate how much electricity a solar PV system is likely to generate in a year.
It provides an average annual electricity output based on your system’s location, size and setup. The calculator uses New Zealand solar data and realistic performance assumptions to give a practical indication of expected energy generation.
This tool is useful for homeowners, designers and professionals who want to understand the potential contribution of solar power to a building’s energy use.
How to use this tool
Determine the average yearly electricity generation capability (i.e. energy yield) of your particular photovoltaic (PV) system by filling in the boxes below.
The estimate is based on historical solar irradiance figures from 18 NIWA climate zones. System losses due to panel soiling (3%), cabling (best practice), inverter inefficiencies (6%), temperature correction (varies according to AS 4509.2) and module mismatch (2%) are applied.
For more detailed reports and calculations for your specific situation, see: