dissadvantages to hydrogen electricitiy (not my spelling)

Hydrogen is currently very expensive, not because it is rare (it's the most common element in the universe!) but because it's difficult to generate, handle, and store, requiring bulky and heavy tanks like those for compressed natural gas (CNG) or complex insulating bottles if stored as a cryogenic (super-cold) liquid like liquefied natural gas (LNG). It can also be stored at moderate temperatures and pressures in a tank containing a metal-hydride absorber or carbon adsorber, though these are currently very expensive. It is possible to store a hydrogen-bearing fuel like natural gas, methanol, or even gasoline aboard the vehicle and re-form it to get hydrogen as needed; this simplifies storage and refueling, but adds cost and complexity to the drivetrain (and reduces efficiency). It is not a very good fuel for an internal combustion engine, being prone to preignition, though BMW, Mazda, and Ford have done some tests; the most efficient way to use it is in fuel cell vehicles, but these are still in the demonstration stage.

Under "Advantages" above, I discussed the benefits of using hydrogen generated from renewable, nonpolluting power like solar electricity. However, as hydrogen fuel has gained political momentum, concern is growing that the inefficiencies of generating, transporting, and storing hydrogen may make it a poor choice if the energy used to generate the hydrogen comes from fossil fuels (whether via re-forming those fuels directly, or by burning them to generate electricity for electrolysis of water). It is definitely more efficient to generate electricity from a fossil fuel, transport it via wires, and use it to charge up a battery-electric vehicle than it is to burn the same fossil fuel in an internal-combustion engine aboard a conventional vehicle; however, it is uncertain whether it is more or less efficient to use that fossil fuel to generate hydrogen for use in a vehicle. If the hydrogen is produced at a central plant, there are inefficiencies associated with generating it, transporting it via truck or pipeline, and storing it aboard the vehicle as a compressed gas or cryogenic liquid; if it is generated at the point of sale by electrolysis, you can replace the inefficiency of trucking or piping the hydrogen with the efficient utility-line transportation of electricity, but you still have the other losses, and you add the fact that a smaller-scale hydrogen generator will be less efficient than a large-scale one. The jury is still out on whether it is more energy-efficient to use fossil fuels to make hydrogen than it is to burn them in a hybrid-electric vehicle, though on balance it looks likely that use of hydrogen will cut down on ordinary combustion-engine pollutants like carbon monoxide, soot, and oxides of nitrogen.

this is where i got it from.

  • Currently more expensive than other energy sources

  • Existing infrastructure has not been built to accommodate hydrogen fuel

  • The process of extracting hydrogen may require fossil fuels (thus generating pollution)

  • Hydrogen is difficult to store and distribute

  • Disadvantages

    Fuel cells are currently very expensive, but since they have a simple construction, mass production costs would become extremely low.

    Prototype fuel cells last only 1/5th as long as would be needed to make fuel cells cost-effective.

    They are energy losers because it costs more to produce hydrogen than is earned by using hydrogen in fuel cells:

    Electricity generated by fuel cells in cars costs thousands of dollars per kilowatt: This would have to fall by a factor of 10 for fuel cells to become economically viable.