Orange hydrogen is the new green

Maintaining global warming well below 2 °C, as stipulated in the Paris Agreement, will require a complete overhaul of the world energy system. Hydrogen is considered to be a key component of the decarbonization strategy for large parts of the transport system, as well as some heavy industries. Today, about 96% of current hydrogen production comes from the steam reforming of coal or natural gas (labelled black and grey hydrogen, respectively). If hydrogen is to become a solution, then black and grey hydrogen need to be replaced by a low-carbon option. One method that has received much attention is to produce so-called green hydrogen by coupling water electrolysis with renewable energies. However, green hydrogen is expensive and energy-intensive to produce. Here, we explore an alternative option and highlight the benefits of rock-based hydrogen (white and orange) compared with classic electrolysis-based technologies. We show that the exploitation of native hydrogen and its combination with carbon sequestration has the potential to fuel a large part of the energy transition without the substantial energy and raw material cost of green hydrogen. Enhancing natural subsurface hydrogen production through water injection could make a substantial contribution to achieving the low-carbon energy transition that is required to limit global warming.