There are a lot of companies working into the PV plant cleaning sector. Only a few of them are specialized into solar plant cleaning. Many operate with unproper tools, endangering the PV plant cells structure walking over it or jeopardizing the surface transparency with inadequate tools (high pressure, cleansers, etc.)
Other companies use tools assembled over an operating machine or industrial non-certified brushes providing unproper results. They are not equipped with specific tools and they need many operators and expose them to security risk on the site. Manual cleaning also exposes the panels to several problems due to a non-uniform washing, which does not meet the expected quality level.