Green hydrogen vs blue hydrogen: What's the difference?

The government will launch the first phase of the keenly awaited National Hydrogen Policy on Thursday. The policy is aimed at boosting green hydrogen production in India and the fuel can be a tipping point for the energy security of the country, which imports 84 per cent of its oil and 53 per cent of gas requirements. 

Hydrogen energy is considerably more efficient than fossil fuels, it can be produced in a sustainable manner and is deemed as a renewable energy source. However, this is not real for all classes of hydrogen energy. 

Green hydrogen and blue hydrogen are the two main kinds of hydrogen oils that have widely different environmental impacts. 

As the economy makes the transition to a zero-carbon future, it's important to understand the difference between blue hydrogen and green hydrogen and how it will impact the country's energy supply mix. 

Also Read: Reliance Industries targets to become world's top blue hydrogen maker

What is blue hydrogen? 

Blue hydrogen is touted as a low-carbon fuel that is used for generating electricity, heating buildings, and powering cars, trains, trucks etc. It is produced by separating natural gas into hydrogen and carbon dioxide (CO2). 

This kind of hydrogen naturally depends on fossil fuels and is just a byproduct of natural gas production. 

According to the International Energy Agency, 96 per cent of hydrogen produced globally is made using fossil fuels such as oil, coal, and natural gas, through a process called reforming, which involves integrating fossil fuels with steam and heating them to approx. 800 degrees Celsius and getting CO2 and hydrogen eventually. The two gases are then segregated. 

The CO2 is usually discharged into the atmosphere where it contributes to climate warming, and the hydrogen is extracted and is utilised in everything from boilers to car engines.

If the carbon dioxide emissions are captured and stored underground, the process is deemed carbon-neutral, and the consequent hydrogen is called "blue hydrogen". 

Also Read: GAIL starts India's maiden project of blending hydrogen into CGD network

What is green hydrogen? 

Green hydrogen, in contrast, is generated by splitting water into hydrogen and oxygen with the help of an electrolyser that may be powered by electricity from renewable energy sources like solar and wind.

Called electrolysis, the process of generating green hydrogen is carbon-neutral and uses an electrical current to segregate hydrogen from oxygen in the water. 

Will green hydrogen constitute the core of India's clean energy mix? 

Experts are upbeat about the potential of this fuel. Like all other fuels, hydrogen when burnt generates energy, but the byproduct of burning hydrogen is water, which makes it the most environmentally-safe fuel. 

Also Read: Time to use green hydrogen instead of coal in cement, steel industries: Nitin Gadkari

Which one is cheaper to produce - blue or green hydrogen? 

The green approach to generating hydrogen is good for sustainability, but it increases the costs, which may impede India's intent to scale up the production of green hydrogen. Adding to that, only a select few domestic companies produce electrolysers, used to generate green hydrogen. The cost of green hydrogen generation is very high currently. 

Meanwhile, the carbon capture, as well as storage equipment in case of storing blue hydrogen, is expensive, causing a rise in the price of the fuel. However, it at least provides for low-carbon fuel generation at a lower cost than green hydrogen.