There is a lot of development being made to capture energy: wind, water, solar, to name a few. However, one of the biggest setbacks in these developments is what to do with the energy after it’s been captured. If it’s not used right away, it’s lost back into the ground. Often times we want to save the energy for a later time when it’s needed.
Enter energy storage. Enter the battery. Enter the fuel cell. Enter the hydrogen cell.
The challenge we have as humans in this world then is to reduce our consumption of fuel, and also find new ways to store fuel that is very renewable. Hydrogen is very plentiful on planet earth.
Hydrogen storage is an interesting concept.
You see, liquid hydrogen boils at −252.882 °C or −423.188 °F which means it’s nearly impossible or ridiculously expensive to store liquid hydrogen. This, on top of the fact that there is actually about 64% more hydrogen in a liter of gasoline (116 grams of hydrogen) than there is in a liter of pure liquid hydrogen (71 grams of hydrogen) doubles to make it seem fairly silly to use hydrogen as a substitute for traditional hydrocarbons (ie. fossil fuels).
Hydrogen gas, on the other hand, has a very high energy density by weight, but obviously to get a gas heavy, it requires quite a lot of volume. This means that the tank to carry the hydrogen is much bigger than a hydrocarbon tank. It is important to keep in mind this only really becomes a problem if the hydrogen needs to be transported. However, if it’s a stationary installation, there is nothing really saying that a large tank is a bad thing. In fact, in North America, we have an abundance of space. This would be somewhat similar to giant propane tanks or gasoline tanks found on the farm.
There are currently two established methods of hydrogen storage in it’s pure form:
- Compressed gaseous hydrogen
- Liquid hydrogen
Compressed hydrogen in hydrogen tanks are pressurized to around 350 bar (5,000 psi) – 700 bar (10,000 psi). These are found in vehicles.
Apparently BMW is working on a liquid hydrogen system for it’s line of hydrogen cars.
However, lots of research is being done on chemical storage techniques, which involve bonding the hydrogen with a chemical that is much easier to store and requires very little energy to extract the hydrogen from the chemical (this is the part that’s being heavily researched).
Now you understand how hydrogen is stored, but how exactly can electricity be used in this process? Well, this is a lesson for Electrolysis.