Since last century engineers have been producing and testing FCVs (Fuel Cell Vehicles), the process to build them is very slow and expensive but will someday provide a car, which is able to run on hydrogen and oxygen outputting zero harmful emissions for the planet. Billions of dollars have already been spent on research and manufacturing and in a few years time experts claim that these vehicles will replace current gasoline-based automobiles.
However, as any other commercial product on the market, the fuel cell cars have their advantages and disadvantages, which begs the question: Will hydrogen be an alternative to gasoline as a fuel for our cars in 20 years time? Some might believe this is a great alternative to gasoline vehicles, since hydrogen constitutes for 90% of all existing atoms in the universe and we will therefore never run out of it, unlike oil. Yet, it is also the lightest element, thus any hydrogen that purely exists on Earth will shoot out instantly to space, therefore the only remaining hydrogen that exists on the planet is in water molecules and in natural gas.
Fortunately, there are currently two ways of producing the hydrogen needed to run these cars: by electrolysis of water or by a process called steam reformation, which separates hydrogen from carbon in natural gas. Both processes have their advantages and disadvantages. For example, using natural gas to produce hydrogen is less expensive than electrolyze water, but if the point of running cars on hydrogen is to reduce the consumption of fossil fuels then this method is not good, since natural gas is a non-renewable source.
On the other hand, electrolyzing water is a slower process that might be more expensive but it is not using any fossil fuels, other than to produce the initial electricity, therefore the whole process involving the production and use of the car is cleaner than using natural gas as a resource. Inside the car there is an even more complex process involving the transformation of pure hydrogen and oxygen to electricity, giving as residue only water and heat energy.
The fuel cell, an electric generator, is able to do this by passing the hydrogen through the anode and oxygen through the cathode; with this each element is separated from their corresponding negative charged particles (electrons), which then go through an electrical circuit to produce about 1. 6 V, just enough to power a small home appliance. Therefore a stack of fuel cells is used, which contains hundreds of cells working in parallel. To further increase the power given to the car’s electrical motor an extra battery has been fitted into the front of the car, which outputs electrical energy when braking.
When enough electrical energy is produced an electric motor converts this energy into mechanical energy, to propel the car. Both these processes have an efficiency of about 80%, yielding a total efficiency inside the car of about 64%. Honda, the manufacture of the leading FCVs has achieved an efficiency of 60% in its flagship hydrogen-based car, the FCX Clarity first introduced in 2008. This complicated method obviously creates a lot of challenges for engineers, which they have to overcome to make these cars as spacious, safe, efficient and cost-effective as possible while not sacrificing any performance.
The two main problems in achieving this challenge are the storage of hydrogen and the durability and reliability of the fuel cell. There are various methods to store hydrogen, either as its currently done, in a high pressure environment to decrease the space each hydrogen atom takes and increase its driving range as the pressure rises, or in its densest form as a liquid at zero Kelvin, or finally inside solid objects through absorption, adsorption and other chemical reactions.
The method currently used, storing hydrogen at a high pressure is the most economic now but is still very expensive, heavy and spacious. The second method increases the driving range of the vehicle since hydrogen in its densest form occupies less space than at any given pressure, but it is not a viable option because the costs increase by far and other issues arise since in the whole process inside the car hydrogen has to be at zero Kelvin, meaning at -273 degrees.
The last method, experts agree is the best choice to store hydrogen in the long run, however the development of this technique is still in early stages. The second problem in building these cars is the durability and reliability of the fuel cells. Right now they are estimated to last for about 120,000 km, however experts say that for the car to be feasible to the general public it has to be able to run for 250,000km before needing a replacement.