For a long time, hydrogen seemed like the future for individual transport and is being talked up by many as a fuel for the future and a key technology against climate change. The idea of a car that produces zero carbon emissions from its exhaust is great but some issues have kept it from the great breakthrough.
How does a hydrogen car work? Basically, the term “hydrogen car” is not correct. It should be called a fuel cell vehicle. And one step further, fuel cell cars are electric cars. The whole thing works like this: The vehicle has a fuel cell and a hydrogen tank. The fuel cell itself generates electricity from hydrogen using the principle of reverse electrolysis. This creates two “waste products”: heat and electricity. However, the electricity does not have to be stored, as in the case of a pure electric vehicle, but is produced when it is needed while driving. A small battery is still available, which works as a buffer for load peaks like strong acceleration. Besides, the battery can store recuperation energy from the braking.
There are two main manufacturing processes for producing hydrogen, steam-methane reforming, and electrolysis. The most cost-effective and simplest way is steam-methane reforming, where high-temperature steam under pressure reacts with methane in the presence of a catalyst. The reaction products are hydrogen, carbon monoxide, and a small amount of carbon dioxide. The carbon dioxide emissions make this process unsuitable for a sustainable future. However, some development towards methane pyrolysis might change this in the future.
Electrolysis splits hydrogen from water using an electric current. In the industry, the method is also remarked as power-to-gas. Electrolysis itself produces no emissions different than hydrogen and oxygen. If the electricity for electrolysis is created from fossil fuels or biomass combustion, carbon dioxide emissions are indirectly linked with electrolysis. That is the reason why it is important to have electricity from renewable sources like hydro, wind, or solar energy.
What is the big problem with hydrogen from electrolysis now?
For comparison, here are the efficiency levels of electric and hydrogen cars.
With a electric car, around eight percent of the energy is lost during transport before the electricity ends up in the battery. Converting the electrical energy to drive the electric motor consumes another 18 percent. Depending on the model, this corresponds to an efficiency of 70 to 80 percent.
Hydrogen cars do much worse here. 45 percent of the energy is already lost in the production of hydrogen through electrolysis. Of the remaining 55 percent, another 55 percent is lost in the converting of hydrogen into electricity in the vehicle. This results in an efficiency of 25 to 35 percent. As a result, the hydrogen car uses two to three times more electricity than the electric car for the same distance.
No sustainable economy can allow itself to use more than twice the amount of energy to drive with fuel cell cars instead of electric vehicles.
Additionally, most electric vehicle owners recharge at home. There is no need for a extremely complex and expensive recharging network of recharging stations as that required for a hydrogen refueling network. Compared with hydrogen stations, electric stations are a lot cheaper and easier to construct.
What about running costs? Even charging an EV at the highest peak rates will be significantly cheaper than refueling with hydrogen.
The hydrogen car can´t keep up with the purchase price either.
For a truly sustainable future, hydrogen can´t be ignored. You just have to use it where it makes sense, and that’s not in the car, but in the stationary area and heavy goods sector.
There is massive potential in electric cars and hydrogen cars to provide a clean, green method of transportation. However, it will only be able to achieve that with the use of clean energy. Otherwise, a car powered by fossil fuels might be the better option.