The different shades of Hydrogen
Hydrogen is expected to play an important role as an energy source in the future. Many of us are aware about the different hydrogen production methods: from fossil-fuel to renewable energy. But did you know that depending on the types of method of production, different colours are associated with hydrogen. For example, the most commonly known to many are “grey” hydrogen and “green” hydrogen, which is basically hydrogen made from natural gas and renewable energy respectively. And there are six other lesser known colors associated with hydrogen. It is also important to note that these colours associated with hydrogen are independent of its physical appearance.
|Color||Method of production||Sources||Costs ($/Kg)||Emissions (Kg CO2 / Kg H2)|
|Brown||Gasification||Coal||1.48 – 2.5||22|
|Grey||Steam methane reforming||Natural gas||0.7 – 1.6||9.3|
|Blue||Steam methane reforming with carbon capture and storage||Natural gas||1.2 – 2.1||1|
|Turquoise||Pyrolysis||Natural gas||1.6 – 2.2||2.5|
|Pink||Electrolysis||Nuclear energy||3.2 – 9.5||–|
|Yellow||Electrolysis||Grid electricity||3.2 – 9.5||–|
|Green||Electrolysis||Renewable energy||3.2 – 9.5||–|
Hydrogen that is naturally found in underground deposits. Hydrogen has been found in underground deposits at 100 m depth with a plausibility of extracting it, similar to petroleum and natural gas extraction. Studies have confirmed evidence of natural molecular hydrogen in shallow deposits in Mali, Carolina bays, Russia. Hydrogen in the free gas phase has been found in some gold mines in South Africa, Canada and Finland. The origin of this H2-rich gas is not fully understood but theories indicate that hydrogen could have been present in the earth’s interior or could largely be present in the earth’s core.
These discoveries are quite recent and, as a result, viable exploration strategies to use these deposits aren’t available. Therefore, we apply different strategies (mentioned below) to generate it artificially. In the future, if extracting this hydrogen at low cost is possible, it could bring a radical change to the economic and financial network of the energy sector.
Hydrogen that is produced by transforming coal into gas through gasification. Hydrogen is produced via coal gasification for more than 200 years, making this process the oldest way of producing hydrogen. China is the world’s leading hydrogen producer where the gas is majorly obtained by coal gasification. Globally, coal gasification is the second major production pathway for hydrogen. Australia and Japan are spearheading the pilot projects in this area with a fully functioning plant in 2019.
Hydrogen that is produced from natural gas, through steam methane reforming. This production method is the most widespread and at the same time the least expensive processes to produce hydrogen. Currently, Asia-pacific holds the majority share of the worldwide steam methane reforming market. In the coming years, Europe is expected to become a lucrative market for steam methane reformers.
Hydrogen that is produced via steam methane reforming and the emissions generated from the process are captured and stored underground via carbon capture and storage (CCS) so that it is not released into the atmosphere. This type of hydrogen is also referred to as a carbon neutral energy source. However, low-carbon would be more accurate since some amount of carbon cannot be captured. Currently, North America has the highest global blue hydrogen production capacity and Europe is expected to overpower in less than a decade. The UK and the Netherlands have plans to develop MW to GW capacity blue hydrogen plants by 2030.
Hydrogen that is produced from natural gas, through methane pyrolysis, and produces solid carbon as a by-product. This type of hydrogen is also referred to as low-carbon hydrogen if renewable sources are used for the energy demand of the process and also, the carbon is permanently stored.
Hydrogen that is produced via water electrolysis using nuclear energy as energy input.
Hydrogen that is produced via water electrolysis using grid electricity as energy input. This would mean that the electricity would come from renewables to fossil fuels based on availability.
Hydrogen that is produced via water electrolysis using renewables as energy input. Undoubtedly, this is the cleanest type of hydrogen currently accounting for around 1% of overall hydrogen production. Currently, North America has the highest global blue hydrogen production capacity and Europe is expected to overpower in less than a decade. The world’s largest electrolyser is located at Air Liquide’s site in Bécancour, to generate 20MW power in total. Many GW-scale green-hydrogen projects are under development which add up to 61GW most of which are in Australia, followed by Europe.
Given that many nations have set a net zero emissions goal. In the future, most of the hydrogen used in fuel cells should be carbon-neutral or low-carbon hydrogen. The most effective way to achieve the goal is green hydrogen. The shift to green hydrogen is inevitable but also slow-paced. However, we need to be aware of the type of hydrogen we are using in order to consciously shift to a greener alternative and reach the targeted emission goals sooner rather than later.