TYPES OF HYDROGEN
We currently have several different technologies that allow us to obtain hydrogen. But not all of them are sustainable. A color code has been established to differentiate the four types, depending on the impact and emissions generated by each one:
• GRAY HYDROGEN: produced with fossil fuels and emits a lot of CO2.
• BLUE HYDROGEN: produced with fossil fuels using carbon capture and storage technologies (less polluting than gray hydrogen). About three-quarters of the hydrogen produced today comes from natural gas. Blue hydrogen could be an initial solution, while green hydrogen production capacity and storage for industries such as steelmaking get underway. But blue hydrogen does not eliminate carbon emissions, only reduce them.
• TURQUOISE HYDROGEN: produced by pyrolysis from natural gas, but it is still a fossil fuel and, as such, is not emission-free.
• GREEN HYDROGEN: a clean fuel that allows energy from renewable sources to be stored and used. It is already considered a substitute for fossil fuels in industries that are difficult to decarbonize and in heavy transport sectors such as shipping and aviation. Both governments and economic sectors have recognized that green hydrogen will be a fundamental pillar for a fully sustainable energy transition. The best known option for producing green hydrogen is the electrolysis of water from renewable electricity. It involves the decomposition of water (H2O) into oxygen (O2) and hydrogen (H2) gases by virtue of a direct electric current traveling through electrodes in the water.
WHICH SECTORS WILL BENEFIT MOST FROM THIS CLEAN FUEL?
• Sustainable mobility: hydrogen fuel cell electric vehicles (FCEVs) represent a revolution in the energy and transportation sectors by using a fuel with a zero CO2 footprint.
• Heavy transport: sectors that are difficult to decarbonize, such as air, sea and rail transport, will find a sustainable solution in green hydrogen. Replacing today's heavy fuels with hydrogen is not so simple. The lower energy density of hydrogen means that such modes of transport will have to be redesigned for heavier loads.
• Energy storage: thanks to its large volume and long lifetime, hydrogen will be able to be stored in the same way as strategic reserves such as natural gas and oil.
• Industry: hydrogen is already used as a raw material in the chemical industry to obtain ammonia, in the petrochemical industry for oil refining, and in metallurgy for steel production. To decarbonize fertilizer production and reduce agricultural emissions.
• Domestic use: several sustainable projects are already underway to replace the natural gas grid with a green hydrogen grid that supplies electricity and heat to homes without producing polluting emissions.
Advantages of Renewable Hydrogen
Renewable hydrogen comes with its own set of pros and cons. However, we believe the disadvantages will diminish as we advance our technologies and cost-effectiveness.
1. Renewable hydrogen is carbon-free.
2. It emits no pollutant gases and offers a zero-emission alternative to fossil fuels.
3. Renewable hydrogen can be produced locally.
4. There are at least three immediate uses for renewable hydrogen in the short term: to replace all uses of fossil hydrogen with renewable hydrogen; to use it in fuel cells in medium and heavy ground transportation; and to use it in aviation and shipping, using e-fuels based on renewable hydrogen.
