Decarbonisation Technology - February 2022 Issue

Green hydrogen to boost a sustainable economy in India An overviewof the significant challenges India is encountering on the technological and economic aspects of the transition to green hydrogen Dr MP Sukumaran Nair Former Secretary to Chief Minister, Kerala and Chairman, Public Sector Restructuring & Audit Board, Govt of Kerala

H ydrogen, the lightest gas and the But the industry nowadays talks widely about grey, blue, and green hydrogen. The context is decarbonisation of human activities to save the planet from an impending climatic disaster through a transition from fossil hydrocarbons to hydrogen as a future energy carrier. The recently published 6th Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), which warns that the goal of 1.5˚C recommended in the Paris Agreement three years ago will be reached by 2030 – a decade earlier than announced previously – has also added a fair amount of momentum to the above. Unlike hydrocarbons, all of which are fossil origin first element in the periodic table of elements, is colourless and odourless. barring a few synthetic fuels, hydrogen upon combustion produces only water and no carbon dioxide (CO 2 ) or other greenhouse gases (GHG).

Here, the colour of hydrogen is attributed to its carbon intensity – a measure of emissions given out during its production. Grey hydrogen is the gas produced from hydrocarbon feedstock, such as oil or natural gas, along with the attendant emissions of GHG, predominantly CO 2 . If the CO 2 emitted is subsequently contained through a process called carbon sequestration – sending the compressed gas to abandoned oil wells or other mines beneath the earth, not to rise up again and cause warming up of the atmosphere and consequent climatic distortions – the hydrogen produced is termed blue hydrogen. Green hydrogen is the gas produced from electrolysis of water using renewable (green) electricity without any emissions throughout its entire life cycle, from production to end use. Hydrogen is an energy carrier that when produced sustainably without GHG emissions is

Grey hydrogen

Reforming or gasication

CCUS

Reforming or gasication

Blue hydrogen

Fossil fuel

Solid carbon

Pyrolysis

Turquoise hydrogen

Green hydrogen

Electrolysis

Renewable electricity

Red hydrogen

Nuclear electricity

Electrolysis

Figure 1 Colours of hydrogen