Robotic cleaning of solar modules gaining attraction in India

Being a country of vast landmass, endowed with the huge solar capacity of approx. 300 sunny days every year, India has realized the potential of solar power. Today, in its march toward sustainable development, India strives to expedite the full potential of clean and cost-effective solar energy, to fulfil all its energy requirements.

However, it is encountering myriad challenges with the toughest among them being the requirement for an enormous quantity of water, which is a scarce resource, to clean the solar panels. As dust builds up on the surface of the PV modules, the capability of electricity generation is constrained.

To avoid generation loss, these panels need to be cleaned regularly. Traditionally, cleaning the solar panels required a large volume of water (1MW Solar plant required an average of 150,000 litres of water per annum). In a country where clean water is a luxury and water scarcity is a concern, the excessive use for cleaning solar panels raises concerns.

Due to this challenge, the industry wants to shift from conventional cleaning methods to a more efficient and less water-intensive solution like dry cleaning or robotic cleaning. India’s Ministry of New and Renewable Energy (MNRE) reported an increase in water usage which they deduced was a result of solar panel cleaning. Following the revelation, it was recommended that operators shift to more efficient utilisation of water and/or a shift to robotic cleaning technology.

Advantages of robotic solar cleaning
India aims to generate 300 GW of solar energy by 2030, so the move to robotic cleaning needs to be a given otherwise it will result in huge water wastage. Furthermore, farm owners require approval from authorities to use groundwater for cleaning, which is time-consuming and may cause a delay in installation.

Grant of permission shall be based on the state/zone in which the plant has been installed. Robotic solar cleaning offers a revolutionary and water-free solution to remove dust from panels. It’s the solution that India requires today to augment the penetration of solar plant installation, while reducing the reliance on water.

Growth of the solar power market is rapid and the efficiency of the PV modules will play a vital role in the scalability of its use in commercial, industrial or utility-scale projects. Solar PV panel cleaning robots help to improve the efficiency of the solar panels clean without endangering human life. If the use of robotic cleaning picks up within the industry, and this grows in line with the increase in the size of solar plants in India, it could be a game-changer.

Another major benefit of robotic cleaning is that it requires less human intervention, which has been a concern for solar players due to the risk to the life of people involved in manual washing. Also, robotic systems work effectively in environmental conditions where water scarcity is a real concern like in the states like Rajasthan, Gujarat, etc. It is the only solution that will ensure the panels’ reliability and power production.

A wonderful additional benefit is that robotic cleaning allows real-time performance monitoring through a centralized management system. The robots send alerts to the control room operating system to communicate any issues, the alert then triggers a change to the cleaning motion on the panels. Using robots also allows the operators to change the cleaning agenda by moving them from one table to the next farm.

Owing to these advantages, robotic cleaning of panels is drawing the attention of farm owners and India is witnessing the much-needed shift.

Robotic infrastructure in India
Currently, in India, fully automatic dry-cleaning robotic and semi-automatic (with pick and place facility) robotic cleaning methods are trending upwards and replacing the manual variety.

To incorporate the fully automatic dry-cleaning robot, it needs to be considered at the design stage of the solar asset where the design for the array layout is underway. Early consideration means the asset can optimise the number of cleaning robots needed and any MMS design requirements can be incorporated from the outset.

This solution is waterless, and is an economical way of cleaning compared to wet cleaning, and it can even yield a higher power generation thanks to minimising soiling loss.

Semi-automatic cleaning involves both robots and manual labour. This type of cleaning is transferred manually from one table to another which decreases the cost compared with fixed robots where you require multiple robots for each row of the PV tables.

This type of bot helps developers to increase their ROI as it reduces two major cost contributors during the operations and maintenance of the plant once online, those being water and manpower. Any reduction to these can reduce the overall cost of running the plant as well as limit risk exposure.

The selection of the “pick and place” robot is assessed based on the type of cleaning material (micro fibre cloth or brush), the weight of the robot, the average speed of cleaning one table, flexibility in adjusting the RPM of the motor, battery backup of the robot battery, charging time for the battery, and warranty and service provided by the robot OEM.

The most effective method is the "fully automatic cleaning robot”, the use of this robot picked up pace in 2019 when the Indian Ministry of New and Renewable Energy expressed its concerns over the excessive use of water for cleaning solar panels and advised developers and operators to switch to robotic cleaning. Since then, India is taking concrete measures to embrace the technology quickly.

As far as robotic cleaning infrastructure is concerned it is in the nascent stage in India but steadily growing in maturity. To fully deploy this technology, a huge investment is required. But the main challenge India is facing is the misconception around the technology. It is assumed that it will reduce employment opportunities in the segment, which is not true. Instead, it will require trained manpower to manage the operations and monitoring.

This will also be an opportunity for local workers to learn new skills and forge into the new field of technology, boosting their knowledge and vision towards the new segment of the industry.

Future prospects of robotic cleaning in India
To increase the solar footprint, developers are aggressively leaning towards the development of large solar plants with millions of PV modules installed. This gives traction to the developers to seek a different method to optimize PV module cleaning with a defined cycle per year. Solutions like robotic cleaning are now a hot topic and are known to deliver the desired outcome.

This gives opportunity and swift pace to the market of robotics for innovation. As an industry, we must constantly challenge our current ways, think differently, think about a new approach or a new technique to optimise our processes, decarbonise our operations and reduce our environmental impact.

Luckily both local Governments and developers are open to innovation, adopting new technologies, and implementing cost-effective and secure methods to augment solar energy generation. This makes the path for robotic cleaning in India smooth and clear. The technology will gain more traction in the months and hopefully, we will see new technologies in the robotic field, which will set the benchmark in the approach towards PV module cleaning.

-- Sandeep Jadhav, Director, Operations & Maintenance, ENGIE India.