Add a pinch of salt for cheaper solar, say scientists


The thin-film solar market could be transformed simply by replacing cadmium chloride with magnesium chloride during the activation process of cadmium telluride, claim scientists at the University of Liverpool, U.K.

In a study published in the science journal Nature, researchers at the University claim that using magnesium chloride – used to make tofu and bath salts and easily extractable the world over – during the manufacturing process of thin-film solar panels achieves the same level of efficiencies at a fraction of the costs of cadmium chloride, and at far lower levels of toxicity.

"We certainly believe it is going to make a big change to the costs of these thin film devices," said Jon Major, lead researcher from the University of Liverpool. "The cost of solar is going to match fossil fuels eventually, but this is going to get us there quicker."

Easily recovered from seawater, magnesium chloride is often used to de-ice roads in winter and to coagulate soya milk into tofu. It is harmless, non-toxic and incredibly cheap, and when applied to cadmium telluride in lab testing conditions, delivered photovoltaic efficiencies that are on a par with cadmium chloride.

"We had to apply cadmium chloride in a fume cupboard in the lab, but we created solar cells using magnesium chloride on a bench with a spray gun bought from a model shop," added Major. "Cadmium chloride is toxic and expensive, and we no longer need to use it. Replacing it with a naturally occurring substance could save the industry a vast amount of money and reduce the overall cost for generating power from solar."

Thin-film, thin margins?

Despite the scientists’ excitement at the breakthrough, skeptical solar experts have questioned just how much of an impact this new technique could have on costs at a scale large enough to impact the industry.

Globally, silicon-based semiconductors claim approximately 90% of the solar panel industry, with thin-film – based on cadmium telluride efficiencies – accounting for just 7%. Nigel Mason of PV Consulting told the BBC that he believes the researchers are being unduly optimistic in their calculations of the impact this new technique can have.

"The development is great for the environmental management and safety of the production process, but the cost of cadmium chloride material and dealing with its safe disposal is a relatively small fraction of production costs," he said.

Early estimations suggest that magnesium chloride approximately 1% the cost of cadmium chloride, but while significantly cheaper, the volumes required may not – at current market share – be enough to drastically alter the price of solar panels, warn experts.