What is hydrogen?
Hydrogen and differnet types of hydrogen are an environmentally friendly alternative to methane, also known as natural gas. It is the most abundant chemical element, accounting for 75% of the universe’s mass.
Water, plants, animals, and, of course, humans contain massive amounts of hydrogen atoms. While it is found in nearly all molecules in living things, it is extremely rare as a gas, with less than one part per million by volume.
Hydrogen can be produced using a variety of resources, including natural gas, nuclear power, biogas, and renewable energy sources such as solar and wind. The difficulty is in harnessing hydrogen as a gas on a large scale to power our homes and businesses.
What is the significance of hydrogen as a future clean energy source?
A fuel is a substance that can be ‘burned’ to produce useful energy. When a fuel is burned, the chemical bonds between the elements in the fuel are broken and the elements combine chemically with oxygen present in the air.
We have long used natural gas to heat our residences, places of business, and power plants that produce electricity. 21% of world’s natural gas is consumed by US alone followed by EU at 12%.
The primary component of “natural gas” from oil and gas fields is methane. Natural gas has replaced coal, the dirtiest fossil fuel that we have historically used for heating and producing electricity, because it is a resource that is easily accessible, affordable, and clean.
Burning natural gas produces heat energy. Carbon dioxide, on the other hand, is a waste product that, when released into the atmosphere, aids in climate change. The only byproduct of burning hydrogen is water vapour.
What are the different types of hydrogen?
Based on the source of its production, hydrogen can be classified into following types:
Green hydrogen
Green hydrogen is the type of hydrogen produced with zero harmful greenhouse gas emissions. It is produced by electrolyzing water with clean electricity generated in excess from renewable energy sources, such as solar or wind energy. Hydrogen and oxygen are separated from water in electrolysers using an electrochemical reaction; no carbon dioxide is released during the process.
Because production is costly, green hydrogen currently makes up a small portion of all hydrogen. Green hydrogen will become less expensive as it becomes more prevalent, just as the cost of wind energy has decreased.
Blue hydrogen
Using a process called steam reforming, which combines natural gas and heated water to create steam, blue hydrogen is primarily made from natural gas. Hydrogen is produced, with carbon dioxide as a byproduct. So, in order to capture and store this carbon, carbon capture and storage (CCS) is crucial.
Due to the fact that the steam reforming process doesn’t actually prevent the production of greenhouse gases, blue hydrogen is occasionally referred to as “low-carbon hydrogen.”
Grey hydrogen
The hydrogen we obtain from fossil fuels, with natural gas being the most prevalent, is precisely the grey hydrogen. Using steam methane reformation, grey hydrogen can be produced from natural gas, or methane.
At the moment, it is both the most prevalent and the least expensive form of hydrogen to produce. Grey hydrogen makes up the majority of the hydrogen used today and is also among the top greenhouse emission contributors.
According to the International Energy Agency (IEA), grey hydrogen production causes emissions of about 830 million tonnes of carbon dioxide each year.
Black and brown hydrogen
These black and brown hydrogen are the complete opposite of green hydrogen and the most environmentally harmful among all types of hydrogen. They are produced by using black coal or lignite (brown coal) in the hydrogen-making process.
To further complicate matters, black hydrogen and brown hydrogen are terms that are frequently used interchangeably to refer to any hydrogen produced through the “gasification” process from fossil fuels.
A fresh brown coal to hydrogen project was recently announced by Japan and Australia. Liquefied hydrogen will be created as part of this project in Australia using brown coal, and it will then be transported to Japan for use in low-emission systems.
Pink hydrogen
Nuclear energy is used for the electrolysis that produces pink hydrogen. Purple hydrogen or red hydrogen are additional names for nuclear-produced hydrogen.
Additionally, the extremely high temperatures produced by nuclear reactors could be used to produce steam for more effective electrolysis or steam methane reforming that relies on fossil gas.
Turquoise hydrogen
This is a brand-new addition to the hydrogen colour spectrum, and scaled production has not yet been demonstrated. Methane pyrolysis, a procedure that yields solid carbon and hydrogen, is how turquoise hydrogen is created. If the thermal process is powered by renewable energy and the carbon is either permanently stored or used, turquoise hydrogen may one day be valued as a low-emission hydrogen.
Yellow hydrogen
The term “yellow hydrogen,” which is relatively new, refers to hydrogen produced by electrolysis using solar energy.
In essence, yellow hydrogen is a variety of green hydrogen. The term “green” describes the kinds of production that use renewable energy to reduce greenhouse gas emissions.
Solar panels are used by yellow hydrogen to capture solar energy and transform it into electricity. The electrolyzers that separate water molecules into hydrogen and oxygen are then powered by that electricity.
White hydrogen
White hydrogen is a type of naturally occurring geological hydrogen produced by fracking and found in underground deposits.
The process of extracting natural hydrogen is energy-intensive and necessitates the use of large machinery and fossil fuels, which defeats the purpose of obtaining it in the first place even though it is equally useful and free of greenhouse gases. At the moment, there are no strategies to utilise this hydrogen.
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