The world requires more energy than ever before, and the demand is rapidly increasing. At this critical juncture, a more sustainable supply and generation system is imperative. The goal is to minimize CO2 emissions to the maximum extent and mitigate the overall environmental impact of energy generation. One potential solution is hydrogen, renowned for its potential to offer a lower-carbon, efficient, and affordable alternative. Hydrogen can be utilized as a fuel in power generation, transportation, and industrial activities. Green hydrogen, often hailed as the fuel of the future, is recognized as a potent source of clean energy. In sectors where emissions are challenging to reduce and alternative solutions are hard to implement, such as heavy industries and long-distance transport, hydrogen and hydrogen-based fuels can play a vital role in the decarbonization process.

This revolutionary fuel holds immense promise in combating climate change and reducing dependence on fossil fuels. Its production using renewable energy sources like solar, wind, or hydroelectric power further underscores its eco-friendly potential.

Types of Hydrogen:

1. Green Hydrogen: Produced from renewable energy sources, offering a sustainable pathway to decarbonization. The electrolysis process relies solely on electricity generated from renewable sources such as solar and wind.
2. Gray Hydrogen: Produced through processes like steam methane reforming and coal gasification, utilizing fossil fuels as the primary input. This process releases CO2 emissions into the atmosphere without carbon capture or storage, contributing to climate change.
3. Blue Hydrogen: Produced using natural gases or other fossil fuels to power electrolysis. Carbon emissions generated during the process are captured and stored underground, preventing release into the atmosphere. While having a lower carbon footprint than gray hydrogen, it still relies on fossil fuels.

The Process:

Hydrogen, though the most abundant chemical element, doesn’t exist naturally as a gas in usable quantities and must be produced through industrial methods such as electrolysis. In this process, an electric current splits water into its basic components, gaseous hydrogen and oxygen. The hydrogen gas is then captured and stored for various applications.

The electrolysis process utilizes two main types of electrolyzers in green hydrogen production:

1. Alkaline Electrolyzer: Utilizes liquid alkaline (typically potassium hydroxide) as the electrolyte.
2. Proton Exchange Membrane (PEM) Electrolyzer: Employs a solid polymer membrane as the electrolyte.

During electrolysis, anodes and cathodes, often made of specialized materials like nickel or platinum, facilitate electrochemical reactions. Water molecules lose electrons at the anode, forming oxygen gas and positively charged hydrogen ions. At the cathode, hydrogen ions gain electrons, producing hydrogen gas. Hydrogen gas is collected at the cathode, while oxygen gas is collected at the anode. This hydrogen can be stored and used for various applications, such as fueling hydrogen fuel cell vehicles or providing clean energy for industrial processes.

To manage excess electricity from renewables during periods of high generation and supply it during low renewable energy generation, battery storage is required. Hydrogen storage systems, such as compressed hydrogen tanks or underground caverns, can store large quantities of green hydrogen.

Production Approaches:

Two production approaches, centralized and distributed, are available for scaling green hydrogen production:

1. Centralized Production: Large-scale electrolyzer plants built near renewable energy sources to produce substantial volumes of green hydrogen for various sectors and industries.
2. Distributed Production: Small-scale water electrolysis installations located closer to end users or within specific industrial complexes, allowing more localized production and reducing transportation and distribution costs.

Environmental Impact:

Green hydrogen production results in water vapor as the only byproduct, making it a compelling solution for reducing greenhouse gas emissions in traditionally hard-to-decarbonize sectors such as large industries and transportation.

Versatility of Green Hydrogen:

Green hydrogen finds application across various sectors, serving as a transportation fuel for fuel cell electric vehicles, offering a sustainable alternative to fossil fuels in power generation, and serving as a feedstock in industrial processes to reduce carbon-intensive materials and overall carbon footprint.

Green Hydrogen Initiatives in India:

In August 2021, India’s Prime Minister, Shri Narendra Modi, launched the National Green Hydrogen Mission, setting a target to produce around 1 million tonnes of green hydrogen per year by 2030. The plan includes a production-linked incentive scheme for electrolyzer manufacturing and financial aid for research and development, aiming to position India as a global hub for hydrogen and fuel cell technologies. The plan also outlines hydrogen adoption targets for key sectors, including ammonia and fertilizers, for more effective decarbonization.