Deposits of a super-rare metal used in highly effective solar panels lie in an unusual place – at the bottom of the ocean. Scientists have found massive amounts of the metal tellurium, a key element in cutting-edge solar technology.
The BBC reports on an undersea mountain 480 kilometres from the coast of the Canary Islands that’s rich in the metal.
About 1,000 metres beneath the surface, the mountain’s outer crust is coated in two inches of rock that contains 50,000 times more of the metal than deposits found on land.
In fact, researchers who found the deposits calculate that it could yield 2,670 metric tons of tellurium — equivalent to one-12th of the world’s supply.
The problem is that mining the tellurium could cause damage to the underwater environment.
Thin-film solar technology leads the way
Cadmium-telluride is one of the second generation thin-film solar cell technologies. It’s far better at absorbing light than silicon, so its absorbing layer can be thinner.
A layer of cadmium-telluride just one thousandth of a millimetre thick will absorb around 90 per cent of light.
As a result, it’s the first thin-film technology to effectively make the leap from laboratory to mass production.
Cadmium-telluride solar modules account for around 5 per cent of global installations of solar panels.
Tellurium – the rarest of the rare earth metals
Tellurium is a by-product of copper mining and there’s an ongoing debate over whether the global tellurium supply can support the growing needs of the solar industry.
Tellurium is also used to improve the malleability of steel and copper, and for other semiconductor applications.
Unlike rare earth elements, tellurium is very rare. Its occurrence in the earth’s crust is 0.001 parts per million, making it scarcer than gold.
It’s so rare, in fact, that recycling tellurium is becoming a priority for solar energy producers.
