A technical advance based on an edible salt could revolutionalise solar power.
The majority of solar cells currently on the market are made from silicon. Recent technology using cadmium telluride (CdTe) has enabled the development of thin-film solar cells that are lighter and cheaper, and which don’t require rigid glass backing.
A major drawback of cadmium telluride, however, is that it is toxic, and still relatively expensive. Not least, in 2009 the price of silicon modules from China plummeted, with the result that cadmium telluride and silicon are in a tight race in terms of cost per watt.
However, the solar market could soon change dramatically. A team of scientists at the Stephenson Institute for Renewable Energy at Liverpool University has found that that magnesium chloride, an abundant cheap salt found in seawater, can work just as well as cadmium telluride.
Professor Ken Durose, director of the Institute, believes that the discovery has the potential to transform the economics of solar energy.
Less convinced are some large solar firms. The science journal Nature, which first published the discovery, quoted a spokesperson for Calyxo, a CdTe firm in Germany, who claimed that the impact on the costs side will be limited. Also quoted was the chief technology officer of major US solar company First Solar, who said, “The CdCl2 treatment step is not a major cost driver in our manufacturing process.”
Intriguingly, when the Liverpool team applied for a patent on its discovery, it learned that last year First Solar had filed an application for a separate patent that referenced magnesium chloride. Dr John Major, who led the Liverpool research told Nature, “They listed every chloride they could think of in the patent,” adding that First Solar could not have known about the discovery when the patent was filed.
Nevertheless, Dr Major hopes that the company will adopt the findings. “It would mean our small-scale lab work can actually have an impact on an industrial scale – and that’s why we do science.”
