Fuel cell buses.
 

Will be interesting to see how this company progresses.

Yes, talk of how fuel cells were going to make the internal combustion engine obsolete were rife in the 1970s, yet here we are 40 years later and they are still 'emerging'.
The Achilles heel is where the hydrogen comes from - the energy required to isolate hydrogen is significant - not to mention the volatility of stored hydrogen.

http://www.sfgate.com/business/artic...to-5768226.php

http://www.usatoday.com/story/money/...-gem/15850643/

Video here:- http://bostonherald.com/business/aut..._fuel_cell_car

James May test drove a Honda hydrogen car on TG a few years ago, it seemed to be a good replacement as it went a lot further than lekky cars.