Is Hydrogen safe?

When we hear of using hydrogen to generate electricity or using it as a fuel, the first image that comes to mind of most people is an explosion.

“Isn’t hydrogen highly explosive ?”

The underlying fact that most people pass by about energy is that whatever the source, using energy come with a risk and requires careful attention. Researchers around the world are carrying out extensive testing, evaluation, and development of hydrogen and it’s infrastructure.

Let’s think again before the explosion image takes over your mind. All energy has a risk. That is why proper handing and safety rules are set for us to follow.

1. Where does the image “Hydrogen = Explosion” come from?

The image of hydrogen as a explosive and dangerous fuel comes from two characteristics of the element:
1. The flammable range is large
2. It can ignite with a very small amount of energy

The flammable range of a given substance is the range of a concentration of a gas or vapor that will burn when an ignition source is introduced. Hydrogen’s flammable range is when concentration reaches 4% to 75% in the atmosphere. Between these concentration percentages a small source of ignition such as static electricity will set fire. But unless the above two conditions occur simultaneously hydrogen will not ignite or explode.

2. Hydrogen is less flammable and dissipates quickly in the atmosphere than gasoline

Hydrogen at it’s gaseous form becomes flammable when the mixture of hydrogen in the atmosphere reaches 4%, but let us not forget that hydrogen is very light. In fact, 15 times lighter than air. If for any reason hydrogen leaks, it will quickly disperse and become difficult to reach the 4% mix for it to ignite. In case it does ignite and burns, hydrogen burns itself out very quickly.

This is evident from the pictures of an experiment carried out by the U.S. Department of Energy shown below. The car on the left carries hydrogen and the car on the right carries gasoline in each of it’s tank. Note that after 1 minute the flame on the left which is burning hydrogen already starts to settle down while the car on the left burning a much heavier fuel, gasoline, continues to burn after 2 minutes 40 seconds because it does not dissipates like hydrogen. Compared to hydrogen, gasoline becomes a longer fire threat.

3. Hydrogen is similar to the handling of natural gas under the high pressure gas safety act (*in Japan)

We live right next to natural gas pipelines and we use it almost everyday. Absolute safety is never guaranteed. Nevertheless we use it because the merits of utilizing it outweigh the risks. Rules and regulations are spelled out under the high pressure gas safer act in Japan for us to use. Since 2003 safety testing has been rigorously carried out. As a result, from 2005 the safety standards under the high pressure gas safety act of hydrogen was lowered to the same level as natural gas used as fuel for taxis.

4. Hydrogen is non-toxic to the human body

Hydrogen is the most abundant element found on the planet. Found freely in the atmosphere and various compounds in our surrounding environment, it is naturally occurring and non-toxic to the human body. The result of a burning hydrogen for its energy content is water; a non-toxic substance to not only the human body, but also to the environment.


Reference:
» Independetn NPO Energy Independence Now (U.S.A.)
» U.S. Department of Energy
» Hydrogen safety newsletter from the U.S. Department of Energy

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