Hydrogen has the potential to be a vital piece of the puzzle in creating resilient, low-carbon energy systems. It emits only water when burned and can be produced using power generated from renewables. It's a flexible energy vector, potentially capable of supporting low-carbon transitions in a range of sectors, from heating homes to powering aircraft. However, the extent of its role remains a point of heated debate, with challenges around its high production costs, transportation and storage. Cormac delves into this topic with Nixon Sunny, a Research Assistant in the Centre for Environmental Policy, who describes how hydrogen is produced and how well it may suit different applications.