Is time for a new article discussing climate and the future of energy! Today editor picks is Hydrogen and how it will (not) help to solve the climate change challenge, despite EU’s billions of dollar in investments.. Indeed in 2022 the number of new hydrogen vehicle registered in Norway, Sweden, Denmark, France, Belgium, Netherlands, Switzerland, Ireland, UK, Spain, Portugal, Italy and Austria sum up for a total of 13 vehicles! (source). too few to fix that global warming things. Let s see why Hydrogen is probably a hype.
Hydrogen is the first element of the periodic table with symbol H and atomic number 1. It is formed by a single proton and a single electron. Hydrogen has no neutron. If we add one we form deuterium with mass number 2 and if we add another one we will form tritium that has two neutrons and mass equal three. These two isotopes are particularly important in the nuclear fusion, but that is an argument for another article…
Hydrogen is the most abundant element of the universe forming around 75% of the known mass of the universe! When in Gas form, if you ignite it in presence of Oxygen, it will burn with a pale blue flame that is nearly invisible in daylight. And the results is guess what? WATER!!!!! no CO2, no carbon monoxide, no hydrocarbons nor nitrogen oxides… Just water, too pure to be drunk! isn’t that amazing? Yes.. but the “amazingness” stops here.
Indeed hydrogen has 2 big problems (and few additional minor one):
- Has low energy density per volume (Bad for transporting it)
- Its gas form cannot be found on earth (Production problem)
Lets analyze each point. As I reported in my article few years ago, Hydrogen gas a a good energy density per Kg (around the 2 or 3 times higher than gasoline), but very low energy density per Liter. So, if want to use hydrogen as fuel for your car you need to pressurize it a lot (usually 600-700 ATM !) You will be driving while sitting on a bomb and in case of incident you should pray that no hole is pinched in the tank, otherwise the rescuer will pick you up with a teaspoon.
Furthermore Hydrogen is very a harsh gas because it consists of small molecules that tend to diffuse into the container wall and brittle it (see hydrogen embrittlement). This means that the tanks have to be coated with special materials, making them very expensive with a limited lifespan (remember you may not want that a 700 ATM metal tank filled with inflammable gas to randomly explode.. )
But there is a bigger problem with hydrogen.. the production. We already know that Hydrogen atoms are abundant in the universe (including earth) , but while in outer space is quite easy to find it in gas form, here on earth is not. Here you find it mostly bounded with oxygen in form of water or with carbon in forms of Hydrocarbons. And this a big problem because those bonds are quite stable.. so if you want to break them to retrieve Hydrogen gas, you need to use quite a bit of energy!
For example if you want to start from Water, then you would ideally need to provide the same energy that you will get it back when you “burn” it. So this means that Hydrogen is not a ENERGY SOURCE but rather a ENERGY STORAGE system… You start from water, use X amount energy to break some bonds and produce hydrogen… Then you oxides that hydrogen back to retrieve X amount of energy at the best.. So is kind of a battery..
Where do we get the energy for retrieving hydrogen from water? Well that depends.. we could use solar or we could burn coal. based on the source of energy that we use the hydrogen is classified into colors (a sort of environmental friendly scale). There are 7 colors (Almost like Power Rangers!) based on the way how is produced :
- Black Uses Coal
- Brown uses lignite,
- Grey uses methane for production
- Blue uses also methane but with a carbon capture technology that traps CO2.
- Pink uses nuclear,
- Green hydrogen uses renewables,
- White is the naturally occurring Hydrogen gas extracted (very little)
Which one is the best for the environment?
well 1, 2 and 3 releases CO2 and thus is not great for the environment. Blue hydrogen has been advertised as climate friendly, but a study from 2021 found out that the CO2 emissions are similar to the one for Grey hydrogen. The reason is because some CO2 escapes in the atmosphere anyway and the capturing/storing process also consume quite a bit of energy! The funny things is that the methods, 1, 2,3 and 4 have similar CO2 emission of the one caused by burning methane directly (which i find quite funny)..
But Green Hydrogen is produced with renewables, so it must be green, right? There is little data available mostly because 99% of the hydrogen is produced with method 1,2, 3, but a study from 2021 claims that green hydrogen is not so clean after all and can get as dirty as grey hydrogen! The main reason is the unreliability of solar source that makes the production inefficient. Also, areas where there is a lot of sun and no people (eg desert), have a shortage of water that is needed for hydrogen production! The same or worst can be expected for wind.
White hydrogen is the best but unfortunately there is very little of it, So we are left with Pink, but is scary because has the word nuclear in it, so this production method only exist in books.
Even If we solve both the above challenges, there are more presented by the fuel cell fabrication and usage.
Indeed despite you could burn the hydrogen and get heat out it, it is more convenient to use in a fuel cell and get electricity out of it. A representation of a simple fuel cell is:
Basically it consist of a membrane that only allows the passage of protons while electrons are forced thought an electric circuit..hydrogen is fed in one side and oxygen in the other.. The atom of hydrogen that cross the membrane, react with oxygen and form water vapor. If you want to know more about this , Wikipedia has great article.
The fabrication of Fuel cells requires a lot of expensive and rare materials such as platinum and iridium and studies found that they may represent a bottleneck in PEM production. Another problem is temperature .. Here is Norway temperature is below 0*C (273*K) at least 6 months per year, and that vapor coming out from your car is gonna freeze instantaneously making a very nice block of pure ice (You could always burn some gasoline to keep the Fuel cell warm!).
As you can see Despite Government continue pumping money on pushing hydrogen technology, there is very little hope that will help us with the climate change… but you cannot expect the people in power to be expert in the subject and make a full analysis. They are just random people taken from the street.
So, as always I hope this article was informative. I also want to say thanks to Sabine Hossenfelder video that inspired me to write this article.