We have been in the segment of environmental consultancy and already contributed to the segment by providing innovative solutions through direct or indirect means, whether it is a Sewage Treatment Plant, Biogas Energy, Waste-to-Energy, Solid Waste Management, or Carbon Capturing and Utilization.
As we were developing new technology for Green Hydrogen generation, during its Life Cycle Assessment (LSA), we identified the chain of reactions between Hydrogen (H2) and Methane (CH4) that can lead to the collapse of green initiatives taken worldwide.
Hydrogen is worse than CO2 for the climate
It has been highly misinterpreting that for the generation of Hydrogen Radicals (H') from Hydrogen, there is only a need for an energy source such as heat or lightning. However, we observed that, in the absence of a catalyst, the following chain of reactions between Hydrogen and Methane in the atmosphere can release energy into the atmosphere.
When the Ultraviolet (UV) radiation coming from the sun increases the atomic vibrations of Hydrogen present in the upper atmosphere, the absorbed energy can break the Hydrogen-Hydrogen (H-H) bond in molecular Hydrogen to produce two Hydrogen Radicals.
H2 + UV energy → 2H'
When the generated Hydrogen Radicals interact with Methane in the upper atmosphere, they form a Methyl Radical (CH3') and molecular Hydrogen.
CH4 + H' → CH3' + H2
The generated Methyl Radical, when interacting with Oxygen (O2), forms Formaldehyde (HCHO) and a Hydroxyl Radical (OH') or Hydroperoxyl Radical (HO2').
CH3' + O2 → HCHO + OH'
CH3' + O2 → HCHO + OH2'
Formaldehyde is a colorless, highly toxic, and flammable gas at room temperature and polymerizes spontaneously into Paraformaldehyde.
Further, the generated Hydroperoxyl Radical will react with the Hydrogen Radical to form Hydrogen Peroxide (H2O2).
HO2' + H' → H2O2
Hydrogen Peroxide plays a significant role in synthesizing tropospheric Ozone (O3) and cycling of HOx Radicals. Also, it has a crucial role in Secondary Sulfate Aerosols and Secondary Organic Aerosols formation in the lower atmosphere.
On the other hand, the Hydroxyl Radical generated can then react with Hydrogen gas to produce Water (H2O) and a new Hydrogen Radical, completing the chain.
OH' + H2 → H2O + H'
These chain reactions will continue until they reach the termination steps, where radicals combine to form stable products.
For Methyl Radicals, two Methyl Radicals combine to form Ethane (C2H6).
2 CH3' → C2H6
Ethane has a 100-year indirect Global Warming Potential (GWP) value of 5.5, comparatively more than Methane, which has a value of 4.
For Hydroperoxyl Radicals, two Hydroperoxyl Radicals combine to form Hydrogen Peroxide and molecular Oxygen.
HO2' + HO2' → H2O2 + O2
Furthermore, the reaction dynamics in the environment may be more complex due to the presence of other reacting species and the involvement of various intermediate compounds. Atmospheric chemistry is much more complex and may involve many steps and intermediates.
Overall, the reaction between Hydrogen and Methane in the atmosphere without a catalyst leads to the formation of various intermediate and final products, including Water Vapor (H2O), Carbon Dioxide (CO2), and other byproducts, depending on the specific reaction conditions. The said reactions are relatively slow and are insignificant contributors to the overall chemistry of the atmosphere.
As we are adopting more technologies dependent on Hydrogen, the increased concentration of Hydrogen in the upper atmosphere can be significant, leading to the chain reactions between Hydrogen and Methane or any other Greenhouse Gas (GHG) independent of any external stimuli.