A big obstacle to the energy transition is zooming into view: the finite supply of the niche metals needed to make the cables, turbines and other bits of kit that power a greener economy. That roadblock loomed larger in the past year as the shortage of fossil fuels caused by Russia’s war prompted energy producers to speed up installation of solar and wind infrastructure. But one vital raw material is not in short supply. Cobalt, a metal used to make batteries that was once known as “blue gold”, has become superabundant. Here are the surprising reasons for this “cornucobalt”. It will come as a relief to carmakers, which feared that shortages could cut short the EV boom, and as a disappointment to legions of artisanal miners in Congo, where a blue-gold rush is still under way. Fortunately for miners elsewhere, many other metals remain rare—making it ever more likely that the green transition will create new commodity superpowers.