The size of a shadow depends on:
- size of the object
- location of the object
- date and time of the day
Taking these into account, the length of a shadow should be estimated accurately when designing a solar system so that row spacing between solar PV modules can be properly decided. Keeping in mind that the sun travels in an arch, therefore both the sun’s altitude (position) and the azimuth must be considered when determining the length of a shadow.