AC Transit defines Hydrogen for a Fuel source

http://www.actransit.org/environment/the-hyroad/what-is-hydrogen/

What is Hydrogen?

The Most Common Element in the Universe

Over 90% of the universe is made of hydrogen. Here on earth, hydrogen combines easily with other elements. When hydrogen combines with oxygen, it makes the water that covers 70% of our planet.

The Lightest Element

It’s 14 times lighter than air. If there’s ever a leak in a hydrogen tank, the hydrogen dissipates quickly into the surrounding air-but doesn’t pollute.

H2O Without the O

In a fuel cell, hydrogen (H2) combines with oxygen (O) to make water (H2O) and electricity.

Cleaner and Safer Than Diesel and Gasoline

While each of these fuels is flammable, hydrogen is not toxic and doesn’t pollute.

Potentially the Fuel of the Future

In the ideal future, wind and solar electric generators provide the power to split water into hydrogen and oxygen. In fuel cells, hydrogen and oxygen are re-combined to produce water and electricity. AC Transit is proud to be leading the way, seeking technological solutions to environmental challenges and demonstrating the practicality of zero-emission fuel cell transit-today.