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
