Secondary energy hydrogen is on the verge of becoming - after or in parallel to coal, oil, natural gas, nuclear fission, electricity, energy efficiency gains, and all sorts of renewable energies - the eighth energy in the octagonal energy mix mankind utilizes, before - perhaps - nuclear fusion may become the ninth. Never in the 250 years of modern anthropogenic energy history was the mix in a steady state, never did a new energy addition fully replace its predecessors; the ever increasing demand needed them all; the relative importance of an individual energy changed, energy multiplicity and heterogeneity grew - and still grow. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.