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The rise of green hydrogen in a global and Irish context

  • 14-01-2022 6:21pm
    Posts: 0

    There's a huge amount happening in terms of development and investment in green hydrogen at the moment, both from a production side but also from a consumption side too so I'm kicking off this thread to discuss the various facets of that both globally and in terms of whats happening locally.

    Note, if you want to talk about whether or not green hydrogen should be part of our grid, please take that to the Energy Infrastructure thread.

    If you think nuclear should do whatever, take that to this thread.

    Otherwise feel free to add any relevant news reports, studies from around the world, press releases, analysis etc etc etc as they relate to green hydrogen, its development, how it may form part of energy storage solutions, its storage and consumption etc etc.

    What is green hydrogen?

    In terms of climate protection and climate neutrality, green hydrogen is by far the best option. Green hydrogen is produced using only renewable energy and does not generate any problematic or harmful by-products. As such, green hydrogen is completely climate-neutral. 

    Green hydrogen is hydrogen that is generated entirely by renewable energy such as solar and wind

    Why does the colour green matter?

    Hydrogen itself is a colourless gas but there are around nine colour codes to identify hydrogen. The colours codes of hydrogen refer to the source or the process used to make hydrogen. These codes are: green, blue, grey, brown or black, turquoise, purple, pink, red and white.

    • Green hydrogen is produced through water electrolysis process by employing renewable electricity. The reason it is called green is that there is no CO2 emission during the production process. Water electrolysis is a process which uses electricity to decompose water into hydrogen gas and oxygen.
    • Blue hydrogen is sourced from fossil fuel. However, the CO2 is captured and stored underground (carbon sequestration). Companies are also trying to utilise the captured carbon called carbon capture, storage and utilisation (CCSU). Utilisation is not essential to qualify for blue hydrogen. As no CO2 is emitted, so the blue hydrogen production process is categorised as carbon neutral.
    • Gray hydrogen is produced from fossil fuel and commonly uses steam methane reforming (SMR) method. During this process, CO2 is produced and eventually released to the atmosphere.
    • Black or brown hydrogen is produced from coal. The black and brown colours refer to the type bituminous (black) and lignite (brown) coal. The gasification of coal is a method used to produce hydrogen. However, it is a very polluting process, and CO2 and carbon monoxide are produced as by-products and released to the atmosphere.
    • Turquoise hydrogen can be extracted by using the thermal splitting of methane via methane pyrolysis. The process, though at the experimental stage, remove the carbon in a solid form instead of CO2 gas.
    • Purple hydrogen is made though using nuclear power and heat through combined chemo thermal electrolysis splitting of water.
    • Pink hydrogen is generated through electrolysis of water by using electricity from a nuclear power plant.
    • Red hydrogen is produced through the high-temperature catalytic splitting of water using nuclear power thermal as an energy source.
    • White hydrogen refers to naturally occurring hydrogen.

    Where can it be used?

    Historically its been used for nearly 2 centuries in various industries. Looking to today, its biggest uses are likely to be in the transport sector (in particular for heavy transport i.e. Shipping, aviation, industrial scale equipment etc), heating and as a storage medium for excess energy when renewables are over producing, which can be consumed later in dedicated power plants.