Hydrogen is the lightest and most abundant element in the universe and is considered the most environmentally friendly fuel. Nearly 65 million metric tons of hydrogen are produced every year worldwide using a variety of methods, including the steam reformation of natural gas, an electrolysis process and or the fermentation of biogas.
Hydrogen is most commonly suppled in cylinders, although it can be stored and extracted from a variety of substances. These include a variety of chemical compounds or metal hydrides. In addition, hydrogen can be reformed from carbon-based fuels such as natural gas (CH4), ammonia (NH3), gasoline and diesel.
Today, hydrogen is commonly referred to as “the fuel of the future”, especially for private and public transportation, which are significant sources of pollution. Toyota, Honda, Hyundai, Mercedes-Benz and General Motors and others are all focusing their efforts on the development and sale of hydrogen fuel cell cars as the supporting infrastructure is being deployed.
The Toyota Mirai hydrogen fuel cell vehicle. (Source: Michal Setlak – Own work)
Hydrogen is a flammable fuel but has been proven to be as safe or even safer than gasoline or natural gas (methane). Hydrogen is 57 times lighter than gasoline vapor and 14 times lighter than air. This means that in the event of a leak, hydrogen rapidly rises into the atmosphere at a speed of 45 mph (20m/s) or 2,100 cubic feet per minute (60,000 l/min). Rather than pooling to cause an explosion, it quickly dissipates and/or burns.
A 2001 study by the University of Miami demonstrated the relative safety of hydrogen-fueled cars compared to gasoline-fuel cars. In the study, a gasoline-fed car fire consumed the vehicle leaving it a smoldering heap of charred steel and melted glass while the hydrogen-fed car fire was over in less than two minutes and the car was virtually undamaged.
Hydrogen car vs. gasoline car fire.