- The overall energy efficiency of hydrogen fuel cell can be seen in the diagram above, the main issue is the massive energy losses when converting electricity to hydrogen and back again it can be seen in the above diagram.
- These losses will push up the price of usage considerably as much more energy is required.
- Currently hydrogen is generated from fossil fuels .
- Hydrogen is classed by the NFPA 70s explosive rating of 4 which is the highest, this is due to the fact only a small amount of oxygen (4%) is required to start a reaction, this makes it more dangerous than petrol when there is a leak. 
- Hydrogen fuel cell cars still require a battery, though smaller as a fuel cell will output a fixed amount of energy which requires buffering to allow of acceleration. Effectively you have a battery ev with a lot of extra equipment.
- With range of BEV’s increase every year and costs coming down, Hydrogen fuel cell cars will be just too expensive to justify for consumer cars.
 http://www.fchea.org/fuelcells#:~:text=A%20typical%20fuel%20cell%20works,molecules%20into%20electrons%20and%20protons.&text=At%20the%20cathode%2C%20the%20protons,combine%20to%20produce%20water%20molecules.  https://4thgeneration.energy/life-cycles-emissions-of-hydrogen/  https://cameochemicals.noaa.gov/chemical/8729