The dream of clean hydrogen has tantalized energy experts for years, but producing it has been tough. Many start-ups think the answer could lie beneath our feet.
Outside the city of Thetford Mines, Quebec, in a region that once supplied the world with asbestos, workers are drilling underground in search of an unusual and potentially vast new source of clean energy.
A start-up called Vema Hydrogen has drilled ... [1952 chars]