How often should solar panels be cleaned?
The cleaning interval is calculated from the site's daily soiling rate: while one wash a year is enough in a humid region with 0.01%/day, at a dusty site with 0.5%/day the interval drops to weeks. In Turkey, in arid regions such as Karapınar, typical practice is 2-3 washes per year.
The right approach is to set a loss threshold, not a calendar. First the site's daily accumulation rate is measured, then it is found in how many days the acceptable loss percentage is reached.
- Daily accumulation is in the range 0.01-0.5%; at a site at the upper end a 3% loss occurs in a week, at a site at the lower end it takes months.
- The length of the dry season, nearby agricultural activity, industrial chimneys and dust-raising roads shorten the interval.
- Spot shading such as bird droppings and leaves requires intervention without waiting for the calendar; the shading of one cell can affect the entire string.
In Turkey, at the arid sites along the Konya-Karapınar line, 2-3 washes per year are typically applied in the sector; in rainy regions such as the Aegean and the Black Sea this number falls.
As cleaning frequency increases, labour and access costs also increase; at this point robotic cleaning options such as ROBEG come up for consideration. Since the return calculation depends on the site size, the soiling rate and your existing cleaning cost, it is worked out on a per-project basis. For a site-based assessment write to us.