Tech Edge

Robots and drones offer clear advantages over manual O&M

Robots have come a long way since their laboratory days to being widely used in manufacturing, farming, the military and even healthcare. In pursuit of emission reduction, countries across the globe are switching to cleaner energy sources such as solar power, and robotic technology has grown to become crucial in this process.

With large-scale capacity additions in solar power, there is a need to carry out regular operations and maintenance (O&M) activities. These include ensuring efficient power supply by cleaning solar modules, plant security, vegetation removal and carrying out repairs. In India, specifically, there are additional concerns caused by higher dust levels, the risk of theft, and temperatures reaching up to 50 degrees in some parts. This adds another layer of challenge for solar installations in the country, and has given rise to third-party O&M players that offer packages of services to relevant parties. Mordor Intelligence estimates that the Indian solar energy market will grow at a CAGR of 40 per cent between 2020 and 2025, and as solar power becomes “mainstream”, it is important that the country embraces automated O&M techniques for future development.


With the rise of massive solar parks and expansions across the country, relying purely on manual methods for surveillance may not be practical. In cases of manual inspection, it would take a few days for faults to be detected, while drones could inspect solar parks in under a few hours. Further, drones are equipped with thermal cameras that capture infrared signatures and can detect defects, dirt and soiling on panels, as well as interconnection failures. Once the defects are detected, they are geotagged and sent to the relevant parties.

Even well before a solar park is developed, drones can be used to survey the entire field to help in the design and construction of the park. The devices can hover over the field to assist in the overlaying of blocks of solar panels, inverters and other components. Using specialised software, the level of detail in the imaging and survey data from drones can help detect shadows and the slope of the terrain, and design the entire transmission layout. The technology is especially useful when planning large solar parks, and it is already being commercially applied in India. For instance, in November 2020, Rewa Ultra Mega Solar Park Limited floated a tender for the identification of land for the development of a 1.4 GW solar park and specified that bidders must use drone-based technology to carry out the inspection.

Robots in construction

Robots are also used in the construction of solar parks. They move down the concrete railing system while affixing mounting legs to the concrete, and are preloaded with panels. The robot places the panels with pre-attached stiffening bars. The system can be operated by a small team, with a single operator being able to extrude the concrete, load panels into the robot, and manoeuvre it. Given the labour constraints in India caused by the Covid-19 pandemic, robots can play a big role in saving time and labour costs in construction. Construction company PV Kraftwaker estimates that the task of installing solar panels, which usually requires 35 workers, can actually be done with just one robot, assisted by three workers, in one-eighth the time. The company also estimates that robots, with their low operational costs, could cut construction costs by more than 50 per cent. However, robots in construction systems do have high upfront costs.

Robots in cleaning

Neglecting to clean solar panels can result in a loss of power. Scientific studies suggest that output can fall by up to 24 per cent per month if panels are not cleaned. In areas with frequent dust storms, such power output losses can be as high as 60 per cent. One of the crucial steps in the O&M process is the periodic removal of dust and soiling from solar panels. The cost involved in this process represents about 25-35 per cent of the total O&M expense. Conventionally, in India, this process is carried out manually twice a month, which requires not just human labour but as much as 8 litres of water per solar panel. Robots can play a huge role in reducing both human involvement and water use in the O&M of solar parks.

Many of the commercially available robots are powered by lead-acid batteries and can be recharged using solar energy. Wet cleaning robots are equipped with wipers, scrub brush water, and detergent for cleaning solar panels. Although it may be ideal to remove water completely from the cleaning process, it may be necessary when the solar panels are soiled heavily with mud or bird droppings.

Developers in India are finding it increasingly difficult to source water for panel cleaning. This has resulted in an increased demand for dry-cleaning robots as they use little to no water. These robots are designed with large microfibre brushes on wheels, which rotate at high speeds to generate air flow and remove dust from panels.

Recent developments and status in India

For larger utility-scale projects, robotic cleaning technologies are an economical alternative. For instance, NTPC Limited’s 5 MW solar park in Dadri used Ecoppia’s fully automated dry-cleaning robot, which reduced cleaning costs significantly to

Rs 152,000 per MW for the entire lifetime of the project. The costs of traditional methods of manual cleaning range from Rs 500,000 to Rs 800,000 per MW per year, with a large part of the costs being attributable to labour.

Several Indian companies and start-ups are gaining and securing large investments as there has been a surge in the demand for robotic cleaning solutions. In January 2020, Noida-based solar cleaning tech start-up Ski-lancer Solar secured funding from Venture Catalysts to scale up the production of its robotic cleaning system, which is capable of cleaning solar modules without water or the need for manual intervention. Before this, the company had received an undisclosed amount of funding from Alfa Ventures, a venture capital fund. More recently, in February 2021, Coimbatore-based start-up Solavio Labs secured a funding of Rs 406,000 from a Canadian innovation fund. This came after the company saw its sales jump by 125 times in 2020. The company specialises in making AI-based robots for cleaning that are compatible with most structures, mounting areas and temperatures.

Many major developers such as NTPC Limited, ACME Solar, Rattan India, SB Energy, Sprng Energy, Engie and Fortum are actively using robotic cleaning systems in solar parks. Large-scale solar parks such as Rewa, Bhadla and Pavagada have already adopted drones and robots in their operations, which only signifies that the technology is becoming cost-competitive.


The biggest challenge with robots and drones is that, at the moment, they are not cost-competitive enough in India to be used as the default option for surveillance and repairs. As of today, labour costs in India are quite low, and many developers, especially in small-scale projects, do not see enough benefit in adopting robotic solutions. Additionally, drones generate large volumes of data, for which operators need appropriate applications or software. With a fleet of multiple drones, there is a need for a dedicated team of experts to analyse this data. If the drone system is not automated, a pilot is required to operate the drones. Even though the operational costs of drone technology might be low and the quality of data high, they come with a need to employ additional infrastructure.

To encourage the adoption of drones and robots, at least among large-scale developers, some effort may be needed from the government. Many developers will likely choose traditional methods of O&M over slightly more expensive robotic technologies to scrape profits. If developers are to embrace robotic technology, they must be incentivised at a policy level in order to avoid excess pressure on water resources.

Robots and drones have changed the way companies view solar project development. These technologies are becoming crucial in planning, construction and, most importantly, O&M. Currently, in India, drones and robots are used in many utility-scale solar parks, but it will take some time before they become economically viable for smaller parks. However, the situation is improving, with many large-scale projects using these technologies for surveillance. With the pressure on water resources and the huge expected growth in solar capacities, automation might just be inevitable. Going forward, the growth in AI technology and the launch of 5G-based internet services will improve its uptake.

By Rithvik Kumar


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