- Blue Hydrogen
Hydrogen obtained through the methane reforming process from natural gas is known as blue hydrogen. In the process of steam methane reforming hydrogen and carbon mono oxide is being created through a chemical reaction. Through the catalyst, water is added to the natural gas to create hydrogen and carbon monoxide.
But according t
o recent research, there are some controversies about its effect on the climate. It has been reported that methane emissions during the process are the reason behind the greenhouse effect, as methane is a potent greenhouse gas.
A ton of methane is equivalent to 36 tons of CO2. Through the table mentioned, we can see how much carbon dioxide is produced and methane is produced.
| Description | Without flue-gas capture Blue H2 production (g) | With flue-gas capture Blue H2 production (g) |
| CH4 consumed in SMR process. | 14 | 14 |
| CO2 produced in SMR process. | 38.5 | 38.5 |
| CH4 consumed to drive SMR | 11.6 | 11.6 |
| CO2 produced to drive SMR | 31.8 | 31.8 |
| CH4 consumed to power carbon capture | 3 | 6 |
| CO2 produced to power carbon capture | 8.2 | 16.3 |
| Total CH4 consumed | 28.6 | 31.6 |
| Total CO2 emitted | 51.7 | 39.7 |
| Total emissions in the process | 139 | 135 |
2. Grey Hydrogen
This relatively lower expensive Hydrogen is also generated from natural gas. Other than natural gases it can also be produced from fuels or fossils. It is a nearly non-renewable form of hydrogen. In the presence of a catalyst, the natural gas is steamed at high temperatures to split into hydrogen and carbon dioxide.
Nowadays grey Hydrogen is widely used around the world, almost 95%. Due to the high production of carbon dioxide, the form of this hydrogen is grey. It is also considered to be the bridging alternative to energy.
On the other hand, it has been noticed that in the process of 1 KG grey hydrogen the minimum amount of carbon dioxide generated is 10 KG.
Therefore, the ultimate effect of generating this kind of hydrogen is negative in respect of nature. It is considered one of the most dangerous for the environment.
Grey Hydrogen is generally used in the industry of chemicals. Making fertilizer and refining oil are two common uses of it. Now to compare the different carbon intensities of different hydrogen the mentioned table can be followed.
| Type of Hydrogen | Carbon Intensity (KG/ hydrogen) |
| SGH2’s greener than green hydrogen | -188 |
| Green Hydrogen through electrolysis | 0 |
| Grey Hydrogen (Natural Gas) | 12 |
| Brown Hydrogen from Coal | 20 |
| Gray hydrogen through sequestration | 12(captured) |
| Brown hydrogen through sequestration | 20 (captured) |
Note: SGH2’s greener than green hydrogen avoids CO2 generation of 29 kg for each kg of hydrogen.
3. Black Hydrogen
It is generated by gasifying black coal. Depending upon the type of coal being used, it has been named black hydrogen. It is the oldest way of generating hydrogen through the transformation of coal into gas. In this process, organic or fossil-based carbon materials are converted into hydrogen, carbon dioxide, and carbon monoxide.
Gasification requires a temperature higher than 700°C. bituminous coal is used to produce this kind of hydrogen, and the gas generated by gasifying this coal is known as syngas. Hydrogen from these syngas can be separated with the help of adsorbers.
This process of generating hydrogen is said to be the most polluting process. Both CO2 and carbon monoxide are the result of this method & both of these gases are not captured throughout the process. It is the opposite of green hydrogen.
Despite all this, black hydrogen is the one that is being used worldwide due to its price efficiency. In recent years, Australia and Japan have announced the launch of a new coal-to-hydrogen project through black or brown coal.Other than this there are other colors of hydrogen available too. Such as pink, yellow, white, and more. Although this fuel can be cheaper and more cost-effective than other fuels in the field of industry. It has been developed for decades. To date, Steam methane reforming is the most economical way to produce hydrogen, more than 50% of hydrogen is produced using this method among the whole world.
4. Green Hydrogen
Hydrogen is generated by splitting water into oxygen and hydrogen. As the procedure requires renewable energy like electricity, it is called Electrolysis. The process of generating hydrogen through Electrolysis requires a very low power of carbon thus, oxygen does not get removed from the atmosphere in this process or vapor to the atmosphere.
The ratio of oxygen and water remains balanced. It does not harm the air quality. Green hydrogen is also known as clean hydrogen and it has many uses. In today’s age, it is a great resource of fuel for electric vehicles Hyundai has announced to produce 5 lakh vehicles of hydrogen within 2030.
In the time it will be used in trains, lorries, and aircraft too. It is also useful in industries like chemical, petrochemical, and steel. Green hydrogen is also usable for domestic use. According to the report of market size and analysis, it has been reported that in the year 2020 market size value of green hydrogen is USD 0.82 billion, and the volume size is 220.0 kilotons. The growth rate from 2020 to 2027 will become 14.24% based on revenue.
