The Hydrogen - Future Transportation

 Liquid and gaseous fossil fuels provide around 65% of the world's energy needs, with petroleum oil serving as the main fuel for more than 92% of the world's transportation. 
Environmental worries about exhaust emissions and global warming have increased along with the exponential annual growth in the number of vehicles on the road. Currently, vehicles are responsible for more than 17% of the world's carbon dioxide (CO2) emissions and around 18% of primary energy usage. Vehicles urgently need to switch to better energy sources since CO2 emissions and rising water temperatures are closely related.While many alternative fuel sources have been suggested, hydrogen energy is one that has a lot of promise since it can cut greenhouse gas (GHG) emissions and local air pollution. 

Hydrogen energy is a secondary energy carrier that may be created from any primary energy source, including fossil fuels, nuclear energy, and renewable energy sources. 
Hydrogen energy may be produced using a variety of techniques, the most popular of which being the thermochemical process of steam reforming natural gas. 
Almost no additional byproducts, save water, are produced during the creation of hydrogen energy. Comparing this thin, tasteless, odourless, and non-toxic gas to any other conventional fuel now on the market, its specific energy level is the greatest.
There hasn't been much hydrogen used in the world's transportation industry. Around 8,000 hydrogen fuel cell vehicles were in operation as of 2017, with 90% of these vehicles originating from the United States and Japan and being refuelled at about 280 different locations. However, more recently, a number of significant automakers have created hydrogen fuel cell electric cars (FCEVs) that may be purchased, including Honda, Hyundai, Mercedes, and Toyota. 
Hydrogen energy is a common fuel choice for a variety of demonstration projects other from passenger transportation vehicles. In order to do this, it is anticipated that there are now 25,000 hydrogen fuel cell forklifts in operation globally.
The three different options available for hydrogen-delivery pathways currently include compressed tube trailers, cryogenic liquid trucks, and compressed gas lines.
Another major challenge that must be addressed to achieve a hydrogen economy is developing efficient onboard storage systems for hydrogen energy in automobiles. Since hydrogen is associated with a very low gravimetric density, a hydrogen-powered vehicle will require a storage device that is approximately four times greater than that of gasoline to store the same energy.
Several different storage routes have been explored to resolve this issue, including compressed gas, cryogenic tanks, metal hybrids, and carbon nanotubes, to name a few. Further research is still needed to reach an economical and efficient storage solution for hydrogen energy in vehicles.