Governments and PV manufacturers around the world are applying themselves to the problem of processing the anticipated 78 million tonnes or so of end-of-life silicon solar modules that will enter the global waste stream by 2050.
In April, four researchers from Australia’s University of New South Wales (UNSW) published an assessment of the approaches developed to date, the economic barriers to their implementation and the potential for material recovery and profit for a PV-upcycling industry. The widely hailed study has put Australia at the forefront of understanding the economic drivers and possibilities ahead.
By 2050 the world will have an estimated 4.5 TW of solar capacity, according to International Technology Roadmap for Photovoltaic data and, “a lot of countries have caught on to module recycling,” said CheeMun Chong, associate professor at the UNSW’s school of photovoltaic and renewable energy engineering and a co-author of the study, A techno-economic review of silicon photovoltaic module recycling.
Early adopters of PV, including China, the EU, Japan, the U.S. and South Korea, have various national programs for dealing with PV waste.
Chong said some governments require manufacturers to take responsibility for modules over their 15 to 30-year lifecycle and pay a deposit on each panel sold to cover their potential default. As a result, the past decade has seen more than 100 patents registered for recycling technologies.
Australia has no plan to encourage manufacturer responsibility and collects no levy against panel default and only the state of Victoria is set to ban used solar panels, batteries and inverters – along with other electronic waste – from landfill, in legislation due to come into force on July 1.
That said, public body Sustainability Victoria is conducting a research project with consultants Equilibrium and accountants Ernst & Young to understand end-of-life management approaches for PV systems. “We’re ahead of a significant waste issue,” said Michael Dudley, strategic lead for product stewardship at Sustainability Victoria. “Panels are still largely in situ but in the next three to five years we’ll start to see significant volumes enter the waste stream, which would then trigger private investment and capacity for reprocessing.”
Dudley said his organization advocates an Australia-wide requirement for handling end-of-life solar systems, adding: “Regulation provides confidence to the private sector to invest in this area. Without a system of shared responsibility, the proposition for recycling isn’t as clear.”
UNSW’s study found without regulation, sending end-of-life solar panels to landfill is the most economical way to dispose of them, but entails a high risk toxic elements used in many panels, such as lead, cadmium and telluride, will leach into soil and groundwater.
And then there’s the sheer volume of material – glass, aluminum, silver, copper and silicon – that could be reused if they were economically recovered.
In Australia, where PV waste is expected to reach 800,000 tonnes in 2047, the economic value of materials contained in that amount of panels was this year calculated by a group of Macquarie University researchers to be somewhere in the vicinity of US$1.25 billion.
Globally, said Chong, if all the materials from the 78 million tonnes of end-of-life panels generated by 2050 could be recycled, “we’re talking US$15 billion in material recovery alone”. That’s not taking into consideration the jobs generated by such a major recycling industry, or the environmental benefits of keeping the recovered materials out of landfill.
“Putting costs aside,” said Chong, “all the materials we’d get back from 80 million tonnes of waste would translate to 2 billion new solar panels – or, in today’s technology, 630 GW of generation.”
Of course, cost is the crux of the matter, and that’s where the work of the UNSW team, led by PhD student Rong Deng, becomes instructive. The researchers’ calculations involved more than 100 variables. In simple terms, the team compared the costs and material recovery values of four methods of dealing with end-of-life solar panels: landfill; glass recycling; mechanical recycling, involving the separation of materials; and thermal recycling – using controlled heat to delaminate and separate materials.
The upshot of the study was that “under certain circumstances, recycling solar panels can be profitable, which is very exciting”, said Chong.
Conditions identified that would improve the viability of recycling included: regulations to discourage landfill disposal; simplified and improved recycling processes focused on increasing rates of materials recovery – particularly of silver and intact silicon wafers; changes to module design that would better facilitate recycling; a coordinated approach by governments and recyclers to building a recycling network; and consideration by manufacturers of how to incorporate second-life materials into production lines.
Chong is seeking funding for a new phase of study and has begun discussions with Australia’s Advanced Manufacturing Growth Center.
“We’re at a point where we believe it’s time to scale up,” he added. “We’ve identified the barriers, identified the opportunity and we’re collaborating with groups outside the university that are advanced in coming up with solutions to the technical aspects of recycling.”
The UNSW academic’s goal is to accelerate those solutions and establish intellectual property for world’s-best PV upcycling practices that Australia could implement and export to global markets.