sábado, 18 de mayo de 2013

The false panacea of the hydrogen car

We have all wondered sometime about how are we going to move when gas isn't cheap anymore. Among all of the possible options, one of the most promising is without doubt the hydrogen car. It has been announced very enthusiastically, and actually the advantages are quite big. In first place, there are no harmful emissions, just a bit of water. In second place, hydrogen is easily obtainable from water, and not necessarily from drinking water, it can be as filthy as you want. But if it's that good, why am I not driving one of them right now?
Well, it's complicated.
The chemical reaction that describes its principle is in fact quite simple:
2H2+O2 --> 2H2O
But there are a couple of problems linked to this. The ones I am going to explain here are not the only ones, but they're the most linked to the car functioning.
The first one is that the reaction is too damn powerful. How powerful would you ask? Well:

That is a hydrogen bomb. The chemical reaction that makes it detonate is the very same that would make the hydrogen cars move. Of course I'm not going to say that it would be exactly the same, the idea is to do it in a very controlled environment and using the energy in an efficient way. The real problem is what would happen in case of accident, since car crashes are unavoidable. Any spark in a badly designed engine would burn in catastrophically ways, so lots of research in super secure storage methods has to be done too. 
Here is another video of the reaction filmed with a high speed camera, again, the reaction is the very same the car would use, but in a controlled environment:

The second problem is kind of more technical, but equally interesting. Hydrogen isn't a source of energy just as oil is; it's more like a way of storing it. The quantity of hydrogen present in the air is too little to be captured and used as an energy source. The most plausible methods of obtaining consist in applying an electrical current to water and harvest the obtained gas. This can be done as a homemade experiment, here in video just for you:

At 1:50 she explains the reaction.
At 2:30 you can see electrolysis, the little bubbles emerging from the battery ends are hydrogen and oxygen (one in each tube). Observe that she grabs them separately so they don't explode.
The problem in using this principle for obtaining energy is how to get that electrical current. Solar energy could be used, but it wouldn't be enough. The only option is to use fossil fuels or electricity, which is obtained in a great amount from fossil fuel. So, sadly sad, the problem of oil dependence is not solved at all just by turning to hydrogen cars.
And I want to use this post to talk about electrical cars too. They don't emit greenhouse gases, they aren't noisy and they don't use gas. Well, actually, the only real part about that is the noise one. Just as it happens with hydrogen, there has to be an energy source  to get the car charged. And most of the grid electricity is obtained by the burning of fossil fuels. Fossil fuels that are not renewable and that release CO2 to the atmosphere. Even though, they could be a nice "meanwhile" solution. In fact, I think the best option right now are the E-hybrid cars, hybrid cars that can be charged with electricity. They actually consume less energy, and they're OK for now. They also have the advantage of clustering the emissions in the power plants, so they are more treatable.
But we don't have to lose of sight the fact of they're not the ultimate solution. Sooner or later we are going to have to just leave oil, and the sooner the better. Nowadays the "best" ways of obtaining fuels are in fact worse than the lack of fuel. I highly recommend you to watch Gasland, it's a documentary about fracking, a method of obtaining natural gas that has consequences like this one:

This is being done worldwide, from the US to the Patagonia. The real solution to the problem does not entirely relies on us, but we can help by adapting our lifestyles, for example by using public transport instead of personal cars and of course by getting informed about the pros and cons of new alternatives.

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