While engineers work on ways to competitively produce hydrogen using renewable sources, other scientists are searching for ways to tap into the Earth’s natural hydrogen reserves. The concept of using hydrogen as green energy has been around for centuries. For now, only 0.1 percent of the world’s hydrogen is considered “green,” according to the World Economic Forum . The study’s authors developed what they describe as an “exploration recipe,” which assesses not only where natural hydrogen could be located, but from where it would be commercially feasible to extract. This is definitely a possibility, as scientists have already found evidence that these hydrogen gas reserves do exist.