There are many hurdles standing in the way of hydrogen becoming widespread as an energy carrier for our vehicles, either by the direct burning of it in internal combustion engines or in fuel cells. Very few hydrogen refueling centers exist today, and the gas is difficult to capture, transport and store. One thing is certain regarding hydrogen, though: it can offer extremely low emissions, as it does in BMW's hydrogen-burning V12 engine.

BMW's Hydrogen 7 had to be tested at Argonne National Laboratory's Center for Transportation Research because the emissions are so minute that most test-beds would not be able to detect them at all. "The BMW Hydrogen 7's emissions were only a fraction of SULEV level, making it one of the lowest emitting combustion engine vehicles that have been manufactured," said Thomas Wallner, a mechanical engineer at Argonne. In fact, Wallner adds, "the car's engine actively cleans the air. Argonne's testing shows that the Hydrogen 7's 12-cylinder engine actually shows emissions levels that, for certain components, are cleaner than the ambient air that comes into the car's engine."

The emissions from a hydrogen car have never been the problem. The problem is getting the hydrogen. The hope is that as technology continues advancing forward, new ways to capture, store and distribute hydrogen will make it cheaper and more environmentally friendly, allowing the world to consider hydrogen as one method of reducing our oil dependence. Details after the jump.