When will the hydrogen economy arrive?

The arrival of the hydrogen (H2) economy has been the subject of many studies. Earlier articles were over-optimistic about the timing and extent of global H2 uptake, and predicted private vehicles as leading the way to a H2 economy. The recent strong rise in the global electric vehicle fleet has inevitably led to a reassessment of the prospects for H2, at least for transport. This review paper examines how researchers over recent decades have envisaged how the H2 economy would arrive, and why it was desirable, or even inevitable; it also looks at the future prospects for the H2 economy. The key findings are as follows: ? Among the leading energy forecasting bodies, particularly the International Energy Agency (IEA), even the most optimistic scenarios predict under 10% H2 penetration by 2050. ? IEA forecasts are very optimistic about the prospects for the introduction of carbon dioxide removal technologies and growth of dispatchable sources of low-carbon energy. ? More realistic IEA forecasts would increase the need for the growth of intermittent energy sources such as wind and solar. The subsequent requirement for energy storage would in turn help the case for H2 adoption. ? No new technologies are on the horizon to decisively tip the balance in favor of H2. ? It is concluded that a global H2 economy is still distant, but it could arise in energy-poor countries such as Japan and South Korea, and it could find a niche in freight transport. [ABSTRACT FROM AUTHOR]