Sustainable Route

Water shortage creates demand for dry cleaning solutions

Cleaning of solar PV modules is one of the most critical activities of solar operations and maintenance (O&M). Solar modules are prone to the accumulation of dust, dirt, bird droppings and other impurities, depending on the project location, which can impact their performance significantly. Thus, they need to be clean­ed frequently to perform at optimum levels. Ro­utine cleaning is a cumbersome task in the case of large solar projects that have thousands of solar panels deployed. It becomes even more challenging if the projects are in arid regions. In the Indian context, most of the larger solar projects are either coming up or have already been de­ployed in dry regions of Rajasthan, Gu­jarat and Madhya Pradesh. Many of these project sites are in regions with wa­ter shortage issues for even basic household and irrigation purposes, and thus, using thousands of litres of water for cleaning solar modules is not sustainable. There have been ins­ta­nces where projects have not been clea­ned properly or at the re­quired frequency owing to water availa­bility constraints. Further, with a greater th­ru­st on environment protection, it is not ad­visable to use such large volumes of water for routine maintenance of solar power plants, which is branded as a green sector. As water shortage issues are likely to get agg­ra­vate in many Indian states owing to un­ch­ecked and wasteful use for deca­des, al­ternative module cleaning solutions are coming up. They can clean solar po­wer modules efficiently without using a single drop of water.

Select available technologies and solutions

Most of these technologies are automatic and do not require manual intervention. Further, they use either microfibre brushes or air or a combination of both to clean so­lar modules without using water. Various solutions have entered the Indian market in recent years to address this serious co­n­cern and developers can pick and choo­se based on their project requirements, cost economics and site conditions. One of the global leaders in module cleaning technology, Israel-based Ecoppia off­ers robotic solutions with completely water-free technology that can reportedly remove 99 per cent of soiling on a nightly basis. These robots are energy indepen­de­nt with their own onboard dedicated so­lar modules that can charge the robot batteries when idle. Further, these robots can clean their on­bo­ard solar panels and mi­crofibre elements on their own. More­over, these robotic solutions are available for fixed tilt as well as single-axis tracker solar installations. The AI-enabled and da­ta-driven ro­bots are connected with Ecoppia’s networks for re­mote monitoring purposes. Another Isra­el-based module cleaning firm active in India is Airtouch. Airtouch 3.0 is the company’s self-cleaning robot solution that does not require water for cleaning. This solution has gentle microfibre wipers that enable to­uch-free removal of soiling particles. A variation of this solution is Air­touch 3.0 por­table, which enables field operators to ma­nu­ally mount the cleaning robot. The company provides another so­lu­tion called AT 2.0 Tracker, which can clean multiple tracking rows through an autonomous vehicle for simultaneous operation of multiple self-cleaning robots. The company uses its cloud-based IoT system for remote acc-ess, control and monitoring of its robots.

There are a few Indian companies as well that have developed innovative solutions in the dry module cleaning space. IT giant Infosys has designed and built a robot that has an integrated vision system for dry and wet cleaning of solar panels. This vi­sion system helps detect dirt and other soiling particles on the panel and wet cleaning is performed only in these areas. This helps reduce water consumption significantly. Fu­rther, the company has a cloud-ready platform that enables fleet management, IoT enablement, smart vision-assisted dry and wet cleaning, integrated wipe system and water tank, and solar panel health monitoring as per the product description. Another Indian company, ECO IMPULSE has developed a dry solar panel cleaning robot called SCR-01. This product does not require any human intervention for control and is autono­mo­us. The solution has in­­­built sensors and weather monitoring sys­­tems for identifying and predicting the soi­ling amount and type on solar modules. The cleaning brush used in this product has nylon microfibre bristles coated with nan­o­­polyurethane particles to ensure scra­t­ch-free cleaning and prevent sticking of dust on the bristles. Further, airflow prevents settling of dust particles on the panels.

Outlook

For solar PV to be a truly sustainable and green avenue for meeting the future power requirements, it is important that the water usage of solar power plants is minimised, especially keeping in mind that more than 250 GW of solar deployments have been planned till 2030. Dry cleaning solutions are a suitable alternative to the present wasteful module cleaning practices. Going forward, it is critical that developers adopt these solutions sooner rather than later, to not only achieve economies of scale, but also help in water conservation.

By Khushboo Goyal

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