Investors had lost faith in Edwin Drake's obsessive hunt for oil when the American entrepreneur finally struck black gold in an underground reservoir in Titusville, Pennsylvania, in 1859. The discovery spurred an exploration frenzy that launched the modern oil age.Now, a new generation of wildcatters are racing to replicate that Titusville moment, hoping to bring about the dawn of a major new energy resource. However, it's not fossil fuels they are looking for, but a commercially viable source of natural – and low-carbon – hydrogen.