The answer is a resounding yes. Soiling, dirt and debris, varies with different areas and also with proximity to different adjacent activities. Typically we think of dust and dirt, which is common to all warm weather climates primarily, such as farming or desert areas.
However there is also greasy debris which is usually associated with proximity to manufacturing areas or freeways. Greasy smoke from manufacturing facilities plus exhaust from vehicles and provide a different cleaning issue. When this grease settles on the solar panels, it is important to not allow it to build up. That we why we use a soap concentrate product which when allowed to sit on the panels during a wash cycle (normally during the hours of darkness) loosens the greasy debris and allow us the opportunity to rinse the debris away. Bird droppings and pollen are also additional examples of types of debris that reduced output from panels.
Wind patterns also impact each specific site differently. Two sites can be closed together, often within a quarter mile and yet still have significantly different soiling rates.
The type of nozzle used is important to ensure that the waste is removed from every square inch of the panel in order to avoid hot spotting and even reverse polarity in severe cases (source: SunPower engineers).
Also a factor is seasonal changes. Our Heliotex Systems address seasonal changes with simple programming changes that vary the frequency and duration of wash or rinse cycles. For example, during a particularly dusty season, we may increase the number of minutes a rinse cycle happens as well as adding a mid-week additional rinse cycle.
Contact Heliotex at 760-837-0390 if we may assist you or you have any questions.