A future "hydrogen economy" will only be as clean and sustainable as the source of energy to produce the hydrogen. Hydrogen can be produced with coal and other fossil fuels, nuclear, or renewable energy sources. Hydrogen is more a battery than an energy source in itself. The focus must be upon renewable energy or society has realized little gain by switching from carbon to hydrogen fuel sources.

ENN News Story - Focus on hydrogen economy has things backwards

As much as "gee whiz" stories abound about new hydrogen fuel-cell technologies, one can't help but wonder if we aren't getting a tad ahead of ourselves. While it's great to have these vehicles to show off, it would be much better if we had a way to produce hydrogen in sufficient quantities cleanly. Or had a way to store the stuff. Or an infrastructure to move it around. Or any number of a host of other major hurdles we need to jump before we are able to reach the vaunted goal of a "hydrogen economy."