Grey hydrogen
Topic: Environment and Sustainable Development · NCERT: Beyond NCERT
Meaning
Grey hydrogen is hydrogen made from natural gas or other fossil fuels, where the CO2 produced is released into the air, not captured. Today it is the cheapest and most common form of hydrogen. However, it adds to global warming, so replacing it is a key goal of hydrogen policy.
Example
Oil refineries and fertiliser plants in India mostly use hydrogen made from natural gas. Every kilogram produced this way releases CO2. That is why the National Green Hydrogen Mission (January 2023) aims to shift these users to green hydrogen.
Don't confuse with
- Blue hydrogen: this is also made from natural gas, but the CO2 is captured and stored.
- Green hydrogen: this is made by splitting water using renewable power, so emissions are near zero. India's standard (2023) is no more than 2 kg CO2e per kg of hydrogen.
Related concepts
- Energy transition
- Energy trilemma
- Energy intensity
- Coal phase-down
- Blue hydrogen
- Green hydrogen
- Green ammonia
- Hydrogen economy
- Green premium
- Carbon capture, utilisation and storage