It might sound like something straight out of the 19th century, but one of the most cutting-edge areas in energy today involves drilling deep underground to hunt for materials that can be burned for energy. The difference is that this time, instead of looking for fossil fuels, the race is on to find natural deposits of hydrogen.Hydrogen is already a key ingredient in the chemical industry and could be used as a greener fuel in industries from aviation and transoceanic shipping to steelmaking. To...