Today, almost 95% of all photovoltaic panels are based on mono- or polycrystalline silicon cells, which use precious silver to conduct electricity.
Now, an Australian solar company, SunDrive, has created super-efficient and cheap solar panels that use more sustainable copper to pull the electrical current from the cells rather than silver. Indeed, the latest tests have shown how copper can serve as a reliable replacement but also can push the technology into new terrain, achieving a world-record efficiency for commercially-sized silicon solar cells of 25.54%. This efficiency surpassed the previous world record of 25.26%, held by LONGi Solar, the world’s leading manufacturer of monocrystalline solar modules.
In 2015, SunDrive took on the challenge of replacing silver in solar cells with copper in order to improve the long-term prospects of the technology. The company was founded by the University of New South Wales (UNSW) graduates Vince Allen and David Hu in 2015 to accelerate solar cell development in Australia.
In the years to come, as part of the fight against global warming, the demand for photovoltaic panels will probably increase rapidly; it was, therefore, urgent to propose an alternative that was more accessible in terms of costs and more sustainable.
Silver is an expensive and finite resource. Copper, on the other hand, is much more abundant and around 100 times cheaper as a raw material than silver. This means the cost of solar modules could plummet if the technology is developed further.
“A lot of people, including myself, have spent many years trying to demonstrate that copper is an economically viable and sustainable alternative to silver,” said UNSW Professor Alison Lennon, who is a SunDrive advisor. “We’ve never been totally able to convince the industry, but that’s what Sundrive has done with this world record. I think this could be a real game-changer for the industry. There will be a lot of interest in how it has been achieved.”
Now the startup has gone from being a small doctoral project in a garage to finally fabricating some of the most efficient industrial-sized solar cells ever produced in Australia, using copper rather than silver. In October 2020, the startup received funding from the Australian Renewable Energy Agency to advance the commercial development of its system that can be fitted to rooftops. These commercial-sized cells recently underwent testing at the Institute for Solar Energy Research Hamelin (ISFH) in Germany, which awarded the team the new world efficiency record certification earlier this month.
The developers say that this method of creating solar cells could dramatically reduce their costs with increased efficiency.
“In order to limit global warming, we will need to install terawatts of solar panels. This will require a lot of metal,” said Lennon. “Silver is a limited resource, and as it becomes more and more scarce, its price will go up, so the cost of producing solar modules will rise as well. Mining silver from lower-quality ores also produces more emissions, making the problem worse.”
“Copper is much more available as a resource, it’s cheaper, and it’s also easier to recycle. The metal from copper-plated solar modules will be easier to recover from old modules and, therefore, may be more easily recycled in the future. This helps enormously from a sustainability perspective.”