The hydrogen economy, like fusion power and space tourism, always seems to be “just around the corner,” but it never seems to get here. The Trends editors started studying hydrogen fuel economics during the energy crisis of the 1970s, and we’ve monitored it ever since. With the increasing geopolitical risk associated with oil and growing concerns over carbon emissions, an economy relying on hydrogen to replace fossil fuels looks ideal at first blush. So, why isn’t it here yet? What are the barriers to implementation? And, when can we realistically expect to see results? We’ll explain.