The idea to use water as a fuel seems an evolution of the scientific fiction “Back to the Future” in which Dr. Brown was putting banana peel in the fuel tank of Velorium, the time machine. But it isn’t something new. The Indian business man Ratan Tata will finance a project to create a car that uses water as fuel. This car will use a technology developed by the Massachusetts Institute of Technology – the MIT, in which water is used to produce hydrogen and this in turns to obtain energy.
The energy that comes from hydrogen in this way is completely clean. When the hydrogen is burning energy is released and the product of combustion is water. We don’t have any CO2 emission and imagine how amazing is it!
Clearly you cannot just produce hydrogen from water: you need to inject energy in the system and that amount of energy is obviously (the second law of thermodynamics is there to remind us) greater than the amount of energy that will be later released by burning the hydrogen. So, the crucial point is to use some sort of “freely available” energy to extract the hydrogen from water.
Hence, one of main challenges is the efficient hydrogen production. Nowadays the majority of processes that produce hydrogen focus on the hydrolysis, but other processes use natural gas and others sources (and most of them produce CO2!), like, unbelievably, starch. If we can produce it at low cost using hydrolysis, we can have the best renewable energy ever because from water we take hydrogen and from the hydrogen combustion we have water, in a perfect cycle (but don’t forget that we need energy to activate and maintain the process!). The reason for consuming energy in this hydrogen extraction cycle is that it is easier to transport hydrogen than solar energy and hydrogen packs much more energy than a battery.
The real benefit in terms of CO2 would come from using solar, wind or another ecological source of energy to extract the hydrogen. However a big challenge remains, that is safety, because the hydrogen, even in low concentration, is very much flammable.
American and Swiss researchers from California Institute of Technology created a device that uses solar energy and water to produce hydrogen using cerim oxide. Today, the efficiency isn’t high – only 0.7%, but they hope it may reach approximately 20% and be, in the future, economically viable. If it becames true we can have an energy revolution.