On July 10, 2020, Prime Minister Narendra Modi inaugurated a 750- megawatt solar plant in Madhya Pradesh’s Rewa, dedicating it to the nation. With this, India inched closer to its goal of increasing solar power capacity from 20,000 MW to 1,00,000 MW by 2022. Under the historic Paris climate change agreement, India had set a goal of generating 40 per cent electricity from non-fossil fuel sources by 2030.

In 2015, under the National Solar Mission, the central government scaled up its plan to increase solar power capacity from 20,000 MW by 2021-22 to 1,00,000 MW. Under the scheme for development of solar parks and ultra-mega solar power projects, the Ministry of New and Renewable Energy (MNRE) had proposed to set up at least 25 similar solar projects within five years.

But, with India’s leap to emerge a solar superpower will leave behind heaps of end-of-life (EOL) solar panels. According to the Bridge to India report released in April 2019, India may generate 1.8 million tonnes of solar photovoltaic (PV) waste by 2050.

“Solar modules are clean and green energy option until they generate power. Once they reach their end-of-life stage, these panels may significantly impact human health and environment,” said Romik Rai, CEO of Dehradun-based Green Assets, a waste-management firm.

The average life of a solar panel is 10-12 years, after which the panels begin to degrade due to climate and other environmental factors like solar irradiance, wind, temperature, moisture, precipitation, and solar spectral characteristics, including UV intensities.

A photovoltaic (PV) module or solar panel is made up of glass, metal, silicon, and polymer fractions. 80 per cent of the total weight of these panels is of glass and aluminium used in the panels. However, the remaining 20 per cent is of heavy metals, compounds, polymers, and alloys. Along with metal and glass, other waste includes insulation material (partially-reusable mineral wool), battery, and electrical devices.

Currently, there is no policy to manage and recycle solar waste in the country. In response to the health and environmental risks of the end-of-life panels, in 2019, the solar waste was categorized as e-waste by the Ministry of Renewable Energy (MNRE).

How India deals with end-of-life panels

The scrap market is currently unorganised. The damaged solar panels are now replaced and not repaired. The replaced panels are stacked or dumped in warehouses.

Of late, some local scrapers purchase end-of-life panels. A few of them extract the metal (aluminium) and glass. For example, in a one KW panel weighing around 15-16 kilograms, the frame is made up of aluminium and weighs 1-2 kilograms, and the remaining weight is of glass. The market rate of scrap aluminium fluctuates daily. For instance, it could be 85 rupees per kilogram. Glass finds its way back to the glass industry, and is sold at 2-3 rupees per kilogram.  In total, the scrap value of 1 KW panel maybe around 200 rupees.

People generally use solar geysers in winters. Not many Indian households use solar energy for electrification. The solar geyser panels are heavy. Glass and aluminium forms 80 percent of the total waste once scrapped, tells Wasim Raja, a trained electrician-cum-technician based in Uttar Pradesh’s district Bareilly.

MR Ansari, a Dehradun-based scrap-dealer said that at present, not too many old panels are available. “I remember scrapping solar geyser panels five-six years ago. I bought old panels installed in a hospital and sold to a bigger scrapper for 35,000 rupees, then,” he said. “I do not know about their fate or how they were recycled. There has been little business of waste solar panels after that,” he added.

Solar waste management is in its infancy in the opinion of Sangeet Sharma, an independent operator and owner of S&N Merchandizer in Dehradun.

Baby steps towards recycling

Scientists worldwide are exploring ways to revive dead PV panels. PV recycling is still at a nascent stage globally. Most countries classify PV waste as general industrial or e-waste.

A group at Bangalore-based Indian Institute of Science (IISc) is probably the first to explore the use of end-of-life panels as a building material and developed a few products to extend their useful life by another 20 to 30 years.

In 2018, the idea struck Monto Mani, associate professor at IISc’s Centre for Sustainable Technologies, when he was adding an extension to his laboratory.

“In 2007, we had built a demonstrating building unit with a roof-integrated building. “We had a few old PV panels scrapped off from a project we did in 2007. We decided to put them to use,” he said. “The new facility was built entirely out of end-of-life PV panels. We made a few other products as well, like a table and chopping board”, Mani told Gaon Connection.

How safe are these panels to be used as a building material? There two types of panels. The silicon-based has a toughened glass top with a polymer – Polyvinyl Fluoride (PFA) – back sheet while the other thin-film panes have a glass top and a glass-bottom (glass-glass) configuration. The majority of the end-of-life panels currently emerging are in the first category, with waste from the latter expected within this decade, said Mani.

“Glass has traditionally been the safest of material. Panels are designed for a working life of 25 years, and the back sheet is extremely durable,” Mani explained. “Since we are unsure of possible toxicity associated with short and long-term exposure to back sheet in the indoor environment, we are using two panels placed back to back, with glass facing outside and inside,” he added.

The glass-glass configuration PV panels offset the risk completely and would be much safer to integrate into the buildings. Any breakage leads to a shattering, like in an automobile windshield, of the toughened glass cover, generally exposing the polymer – Ethylene Vinyl Acetate (EVA) – that encapsulates the PV cell. EVA is very stable, however, its long-term environmental implications when disposed of are still emerging.

Mani and his team developed a few other products using discarded solar panels. For example, small panels have been converted into chopping boards. The glass top of the panel is made of toughened glass and can withstand the normal wear and tear associated with kitchen knives. There is a texture on the top of these panels which improves the grip. However, care must be taken to avoid impact from sharp objects.

The team is planning to build rapid self-powered sanitation units that can power its own flushing system, lighting, and possibly disinfection as well, entirely out of end-of-life PV panels. Mobile charging stations and Wi-Fi points powered by streetlights, bus-stops installed with low-efficiency EOL panels, installation of low-efficiency EOL panels on handcarts, and tents for street vendors are also under consideration.

Europe, which has specific regulations for PV waste, most of the waste is currently sent to conventional laminated glass and metal recyclers. There are dedicated recycling facilities for thin-film modules in some countries, but a first-of-its-kind c-Si module recycling facility has become operational only recently (July 2018) in France by Veolia.