This older (2006), informative article from Popular Mechanics gives a good overview on Hydro energy, its potential uses, and shortcomings. The dollar values in the charts for the costs for Hydrogen produced by electrolysis using Photovoltaics (PV) solar has dropped dramatically due to the huge drop in PV solar panels and the significant increase in solar panel efficiencies. The one issue which is conveniently overlooked is the massive amount of fuel wasted as HEAT – for gasoline/diesel, about 65% of every gallon is lost as HEAT. Hydrogen fuel burned in an ICE vehicle would have similar HEAT numbers, and would equally contribute to climate change (global warming). If anyone has current numbers on the fuel wasted as HEAT in Hydrogen fuel cells please post them in the comments. Click here or on the pdf file to learn more.