The Hydrogen Grand Challenge

More than 90% of the world’s growing energy demand is satisfied by fossil fuels (BP Statistical Review …, 2015)1. One consequence of the unrestrained use of this technology is the continuous increase of the CO₂ level of the atmosphere2. There are also the challenges associated with the limitations of the corresponding resources (Hubbert, 1956; BP Statistical Review …, 2015). Climate change as a consequence of the growing CO₂ level (see text footnote 2, ESRL Global Monitoring Division, 2015) has been identified as one of the most critical challenges facing mankind and requires immediate action: “The Paris Agreement aims to strengthen the global response to the threat of climate change, ( … ) by low greenhouse gas emissions development, in a manner that does not threaten food production” (United Nations Framework …, 2015). How to reach the corresponding significant reduction of CO₂ emission by 2050 is not defined in this document, but it implies that mankind must transform its energy technology from a fossil to a renewable basis. Numerous studies and publications have indicated that the sun’s energy and its derivatives (wind, water) are by far sufficient to supply world’s energy demand (see, e.g., Smalley, 2005; Züttel et al., 2010); but the large daily and seasonal power variation of renewable energy is an additional complication for a wide spread replacement of fossil energy by renewable energy.