Casting Light on Growing Solar PV Waste

In the absence of laws and a formal recycling ecosystem to deal with discarded panels, an environmental problem is likely to escalate

India’s clean energy march will need solar power to reach its objective. The country has made rapid progress in increasing installed solar capacity from 2.6 GW in March 2014 to 60.8 GW till September 2022.

Solar is attractive for low tariff; solar is abundant because of India’s location in the tropical belt; and solar is India’s most potent talisman in the long battle against climate change.?

However, with increasing installations – on ground and rooftop – comes solar photovoltaic waste. The management of this waste isn’t governed by any policy or regulations, which explains the lack of accountability of producers and the absence of a formal recycling ecosystem. As a result, it ends up in landfills, playing its role in harming the environment.?

Busting Misconceptions?

“The common notion is since PV panels last for about 25 years and the solar boom in India happened in 2010, the installations are still several years away from reaching their end-of-life stage. The problem with such thinking is it overlooks the fact that waste is generated at various stages in the lifecycle of a panel,” says Rushali Shivprasad, the custodian of Social Alpha’s Solar PV Waste thesis. “For instance, panels damaged during transportation and installation are discarded. Modules could develop snags during operations, leading to their removal. Other factors such as natural calamities, marked temperature changes and disruption in voltages accelerate degradation,” she explains.?

According to a report by the Delhi-based thinktank Council on Energy, Environment and Water (CEEW) , India had generated “a cumulative PV module waste of 285 kilo tonnes, as of FY21”. The same report states that by International Renewable Energy Agency (IRENA) estimates, “the global PV waste will touch 78 million tonnes by 2050, with India being one of the top five PV waste creators”.

What Works?

Currently, PV panels are of interest to bulk recyclers who are keen on salvaging glass and aluminium frames. They don’t focus on high-value materials such as silver, cadmium, tellurium, indium, gallium, and germanium, which form a minuscule 1% of the module mass. That’s also because recovery of these elements is expensive and complicated, and there are hardly any technologies in India to accomplish this difficult task on a scale.?

There are three steps to recycling a solar PV panel:??

1. Disassembling, which involves removal of metal frames and cables and recovery of aluminium and copper
2. Delamination, wherein laminated components such as the encapsulant, glass layer and back sheet are separated to obtain the solar cells
3. Metal recovery, the most challenging of all, can be done through chemical etching or metallurgy to retrieve precious substances

There are three ways to carry out delamination – thermal (applying heat), mechanical (crushing and separation), and chemical (dissolving in solvents). “Though heat and mechanical processes are popular, Social Alpha is keen on exploring chemical delamination techniques as they yield maximum undamaged cells,” says Rushali.?

For metal recovery, solar cells are etched with acid or other chemicals to retrieve silicon wafers or compounded semiconductors. Rigorous etching removes impurities and yields high-grade silicon wafers, which can then be used in the manufacturing of new cells. The spent acid is treated to recover silver, copper, cadmium and tellurium.?

Recycling is important for at least two reasons:??

1. Environmental pollution?
2. Resource management?

Environmental pollution

Cadmium and lead in the panels are carcinogenic and can leach into the soil and enter groundwater systems when dumped in landfills. So is antimony, found in the glass encasing of PV modules. This hazardous waste is dealt with in a cavalier manner.?

Resource management

Many of the metals used in PV panels, such as aluminium, are sought after across industries. Moreover, demand for precious metals such as cadmium and tellurium could see an exponential rise if thin-film technologies gain more popularity. Hence recovery of metals from waste PV panels is imperative to reduce extraction of virgin metals and curtail resource loss.?

Social Alpha Perspective?

“Social Alpha is looking at chemical processes for recycling and recovery since they are efficient and less polluting than existing alternatives. At present most of these technologies are at a nascent stage and confined to the laboratory. Additionally, we are focusing on technologies which ensure increased efficiency of thermal and mechanical recycling processes with focus on recovery of metals and undamaged silicon cells,” she says.??

“Our focus will be on early-stage startups who are into R&D or prototype-building. We would help them build connections with scientific labs and the pool of experts in our network. This would enable them to accelerate their lab-to-market journey.”?

Since there is no infrastructure for sophisticated recycling processes, the ecosystem must be built from scratch. “Developing a supply chain for PV waste is a crucial component in this ecosystem. At the same time, a market needs to be developed for the steady consumption of recycled materials in various industries,” she says.??

However, for starters, India needs a law that specifically deals with solar PV waste. That would pave the way for other parts of the puzzle to fall into place.?

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