Germany Unveils a Hydrogen-Powered Passenger Train (fortune.com)

An anonymous reader writes: The world's first CO2-emission-free train powered through hydrogen was unveiled this week in Germany. The Coradia iLint, created by French company Alstom, was presented at the Berlin InnoTrans trade show on Tuesday. The train's energy comes from combining hydrogen stored in tanks on the train with oxygen in the air. The energy is then stored in lithium-ion batteries. The train's only emissions are steam and condensed water. The train also has lower noise levels than diesel trains, emitting only the sound of its wheels on the track and any sounds from air resistance at even its highest speed of 140 kilometers per hour (about 87 miles per hour). The train has the ability to travel up to 800 kilometers (497 miles) and carry up to 300 passengers; it's the worldâ(TM)s first hydrogen passenger train that can regularly operate long journeys.

Comments

It's missing the full picture

[PhantomHarlock]

Currently it is incredibly energy intensive to separate hydrogen from oxygen. What power plant is powering the separator? If it's anything but nuclear, hydro, solar or wind, then it's powered by whatever fossil fuel is doing the separation, and at a much lower efficiency than simply putting diesel fuel into a diesel-electric or directly powering an electric train by overhead catenary. In the end you're just centralizing the pollution.

If the separator is run by a non-fossil fuel source, then more power to them.

How efficient is hydrogen really?

[harrkev]

OK. How efficient is hydrogen, really? Shout out to all of the chemistry majors out there who might answer this.

One of the reasons that fuels work, from my understanding, is that you start with a small number of molecule, combust them, and get a larger number of molecules with more heat. The heat increases the pressure, and the increase in the number of molecules increases the pressure.

Example: combustion of alcohol:

C2H6O +3O2 --> 3H2O + 2CO2

We start with four molecules on the left, and get five molecules on the right. Even if the reaction was not exothermic, we would still get a pressure increase good for pushing a piston.

Now, when we burn hydrogen, we get a decrease in the number of molecules (goes from three down to two):

2H2 + O2 --> 2H2O

So, yes, we get increased pressure due to heat production, but we get decreased pressure due to fewer molecules.

So, I guess that my question is: when burning a fuel, how much pressure created is due to the typical increase in molecules, and how much pressure is due to heat?