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What do the different “colors” of hydrogen mean?

Hydrogen Molecule

Hydrogen Molecule

Hydrogen is an invisible gas, and it does not smell. But why is there so much talk about different colors of hydrogen?

It is because not all hydrogen is created equal. Hydrogen can be produced in a number of different ways. The different colors are assigned to hydrogen depending on how sustainable its production process is. After all, if you are using hydrogen to generate the energy for your car, plane, or to heat your house, there is no benefit to the environment if this hydrogen were to be generated by power from a brown coal burning power plant.

The color codes are not really universally standardized. In some countries this kind of hydrogen would be called Black Hydrogen. For our purpose we will concentrate on Grey Hydrogen, Blue Hydrogen, and Green Hydrogen, the three most popular hydrogen designations used in the US.

Grey Hydrogen

Production of Grey Hydrogen

Production of Grey Hydrogen

Most of the hydrogen produced today is grey hydrogen. It is made from fossil fuels or natural gas. It is relatively inexpensive, but it is unfortunately the least sustainable form of hydrogen production. For every single pound of hydrogen generated, 10 pounds of carbon dioxide are released into the atmosphere. This is not a solution for future sustainable energy generation. At best, we can look at it as a bridge technology as we are trying to get away from fossil fuels. Its impact on climate is negative overall. Not really a step forward.

Blue Hydrogen

Blue Hydrogen Production

Blue Hydrogen Production

The very same processes to create grey hydrogen are used to produce blue hydrogen. The significant difference is that CO2 is captured during the process and stored separately. No CO2 is allowed to escape into the environment. The process is called CSS – standing for “Carbon Capture and Storage”. But storage can be quite expensive and there are logistical hurdles to take. Blue hydrogen is seen by many as a realistic alternative because it has a significantly lower CO2 impact on the environment than grey hydrogen, making it more sustainable. However, blue hydrogen production does not eliminate CO2 emissions into the atmosphere completely. It seems to be more ecologically friendly than grey hydrogen, but it cannot be the final solution.

Green Hydrogen

Green Hydrogen from Wind Energy

Green Hydrogen from Wind Energy

Green Hydrogen from Photo Voltaic Panels

Green Hydrogen from Photovoltaic Panels

Now we are coming closer to real sustainability. Renewable sources such as wind and solar power are used to generate the energy to produce green hydrogen. The hydrogen and oxygen molecules are separated using electrolysis, a technique applying electrical energy to water. Using renewable energy sources, this form of hydrogen follows an entirely different production process than that of gray or blue hydrogen. The technique employs electrolysis—the separation of hydrogen and oxygen molecules by applying electrical energy to water. This is a link to a short video that explains the procedure:

Utilizing renewable sources instead of fossil fuels is crucial for the production of green hydrogen. It creates a closed loop of sustainable energy in which harmful gases are never a byproduct of the process, making it the ideal alternative to fossil fuels. Green hydrogen is certainly the best choice for mobile and stationary applications.  But its production and storage present certain challenges. The environmental advantages of green hydrogen are convincing, but there are still people who believe that producing this clean energy source is not yet practical. This is where our  MySky ECO Clean Aviation Project steps in.

The use of green hydrogen is more challenging in aviation than anywhere else. But we have a plan for its sustainable generation and safe storage.

An early adopter of photovoltaic system power generation in the aviation industry was Granite Air Center at the Lebanon airport in New Hampshire. They are using their system to cover their energy needs on the ground. But imagine, you would use such a system to recharge the batteries for electric aircraft or produce your own Green Hydrogen which could be used on the ground or to power aircraft of all sizes.

Granite Air Center Hangar with Photovoltaic Panels


For more details about this succesful hangar project follow the link: