Is Mining Tellurium From Bottom of the Sea Worth the Risk?
Scientists have just discovered massive amounts of a rare metal called tellurium, a key element in cutting-edge solar technology. As a solar expert who specialises in exactly this, I should be delighted. But here’s the catch: the deposit is found at the bottom of the sea, in an undisturbed part of the ocean.
People often have an idealised view of solar as the perfect clean energy source. Direct conversion of sunlight to electricity, no emissions, no oil spills or contamination, perfectly clean. This however overlooks the messy reality of how solar panels are produced.
While the energy produced is indeed clean, some of the materials required to generate that power are toxic or rare. In the case of one particular technology, cadmium telluride-based solar cells, the cadmium is toxic and the telluride is hard to find.
Cadmium telluride is one of the second generation “thin-film” solar cell technologies. It’s far better at absorbing light than silicon, on which most solar power is currently based, and as a result its absorbing layer doesn’t need to be as thick. A layer of cadmium telluride just one thousandth of a millimetre thick will absorb around 90 per cent of the light that hits it. It’s cheap and quick to set up, compared to silicon, and uses less material.
Curt Carnemark / World Bank