We know that renewable energy can help the world to wean itself off fossil fuels, but keeping up with green-energy demand is creating another problem. Countries such as Germany, which has committed itself to a low-carbon future, are finding themselves short of the raw materials required to manufacture wind turbines and solar panels. In particular, metals such as copper, cobalt, platinum-group metals and rare-earth elements such as indium and germanium are in short supply.

But now scientists in Germany are developing new ways to find these precious materials. Using drones equipped with special cameras and sensors, scientists from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Dresden are analysing the way light bounces off underlying rocks, to discover metals deposits. Each mineral produces its own characteristic light reflection, due to the specific shape and size of its crystals. In addition, the scientists are developing a laser-beam sensor to identify minerals that glow brightly due to fluorescence.

These non-invasive methods avoid hillsides being carved up by diggers, and enable mining companies to use less disruptive and safer ways of extracting minerals. Writing in the latest issue of the HZDR magazine, Discovered, the scientists showcase how these techniques have enabled them to pinpoint rare-earth elements in Finland and Namibia.