Green hydrogen is a game changer in the global energy transition. Unlike conventional hydrogen, it is produced using renewable energy sources such as solar, wind, hydro and biomass, eliminating harmful emissions. With global hydrogen demand at 70 million tonnes annually and rising, green hydrogen offers a clean, scalable solution to support net-zero goals and drive a carbon-neutral economy. It is estimated that the annual use of Hydrogen in India will go up from 5-7 million tonnes currently, to 15-20 million tonnes by 2030. If India has to keep its promise of taking non-fossil energy capacity to 500 GW by 2030, meet 50% of its energy requirements from renewables and reach Net Zero by 2070, the role of GH cannot be emphasised enough.
Hydrogen Goes Green: Here’s What You Need to Know
GH is hydrogen which is produced through the electrolysis of water using renewable sources of energy. This process uses an electrical current to separate hydrogen from oxygen in water. It is an environmentally friendly gas as it does not add to carbon emissions. The International Energy Agency (IEA) highlights that the use of renewables for obtaining GH could prevent the emission of 830 million tonnes of CO₂ annually, which would otherwise be released if hydrogen were produced from fossil fuels.
It is termed ‘Green’ because it is produced using renewable energy, ensuring that the fuel remains clean and environmentally friendly with zero pollution.
How is GH produced?
Green Hydrogen (GH) production involves a multi-step process, with key inputs of renewable energy and ultra-pure water feeding into the electrolysis stage.
Renewable Energy Supply: Power for GH production is primarily sourced from dedicated renewable energy generators, such as solar farms or wind turbines. To ensure a continuous and stable power supply for the electrolysis process, especially during periods of low renewable energy generation (e.g., night-time for solar, calm periods for wind), a Battery Energy Storage System (BESS) is integrated. The BESS stores excess renewable energy when available and discharges it when needed, maintaining a consistent power feed.
Water Treatment: Simultaneously, water undergoes a rigorous treatment process to achieve the ultra-high purity required for electrolysis. The selection of a water source—groundwater, treated wastewater, or seawater—dictates the initial pretreatment steps, which typically include filtration and softening. This is followed by reverse osmosis, often in a double-pass configuration, to remove salts and a significant portion of impurities. Finally, technologies such as mixed bed ion exchange or electrodeionization (EDI) are employed to eliminate any remaining trace ions, ensuring the water is ultra-pure and suitable for efficient electrolysis.
Electrolysis: Both the precisely controlled renewable energy supply and the ultra-pure water are then fed in parallel into the electrolyzer, where the electrochemical splitting of water into hydrogen and oxygen occurs.
Storage and Usage: Hydrogen is then stored and used across industries (steel, fertilizers, refineries), for transportation and power generation.
What are the properties of GH?
GH has certain properties which make it unique.
- Zero-emission fuel: GH produces no greenhouse gases or pollutants when used, with water vapor being the only byproduct.
- High energy density: Hydrogen has a very high heating value of 120 MJ/kg, which is significantly higher than other fuels like CNG (45 MJ/kg).
- Lightweight: Hydrogen is the lightest element in the universe, making it easy to transport and store.
- Highly combustible: It is a highly flammable gas, which makes it an effective fuel source. However, it also raises safety concerns.
- Versatile: It can be used flexibly across various applications, including transportation, industrial processes and energy storage.
- Risk of Leakage: Hydrogen is a small molecule and hence there is a much greater risk of leakage.
GH’s properties make it a promising clean energy carrier for the future, particularly in hard-to-decarbonize sectors. However, it needs to be stored and transported with care.
What causes changes in the colour of hydrogen?
Green is not the only colour of Hydrogen. It is available in various other forms viz. Purple/pink, Yellow, Blue etc. Below is a snapshot of the various categories and the kind of carbon footprint each category leaves.
What are the uses of GH?
GH is rapidly gaining momentum among industrial users, offering a compelling balance between environmental sustainability and economic viability. Unlike grey hydrogen, which emits 9–11 kg of CO₂ per kg of H₂, GH enables emissions-free production while offering long-term regulatory and financial benefits.
As a flexible energy carrier, GH’s versatility allows it to be utilized across various sectors—it can power transportation, generate electricity, support industrial processes as both feedstock and fuel, provide heating solutions and enable the storage of renewable energy. It is used in grid storage, shipping, refineries, fertilizers and the steel industries.
It also offers huge export potential in Japan, Europe, South Korea and Singapore where renewable energy (RE) costs are much higher or sub-Saharan Africa and South-east Asia where RE capacity is much lower.
Why is India at an advantage?
With its abundance of low-cost renewable power, (as of October 2024, renewable energy-based electricity generation capacity stands at 203.18 GW, accounting for more than 46.3 percent of the country's total installed capacity), India has the potential to become a major producer of GH. The most economical production sites will likely be those with an optimal combination of abundant renewable resources, space for solar or wind farms, access to water and proximity to large demand centres.
As with many emerging industries, GH requires dedicated industrial policymaking. Supportive policies, which have been widely used in the energy sector to promote renewable electricity, can provide valuable lessons for the GH transition. Ultimately, the future lies in transitioning from grey to blue and eventually to GH.
What are the challenges?
Hydrogen holds promise as a clean energy source, but significant hurdles remain for mainstream adoption.
The True Cost of GH: Genuine GH requires renewable energy, but reliance on variable solar and wind increases costs, including infrastructure. Establishing a robust market for GH across various sectors is crucial for scaling up production while ensuring economic viability.
Limited Renewable Access: Relying on renewable sources like solar and wind for electrolysis can be challenging due to their variable nature, impacting production consistency.
Emissions Beyond Production: Transporting hydrogen, often as ammonia or methanol, adds 20–25% more emissions, reducing its green advantage. Additionally, GH production can be energy-intensive, leading to potential energy losses.
Questioning the Green Label: Some communities may have concerns regarding the safety of hydrogen production and usage, requiring education and addressing potential risks.
Regulatory and Infrastructure Gaps: A lack of standardized compliance and regulations across international markets complicates large-scale adoption. Infrastructure support, including dedicated storage terminals, pipelines, and modernization of existing plants for GH infusion, is critical for an efficient transition.
Policy Incentives and Industry Commitment: Achieving GH scalability requires strong policy incentives, mandates for transition, and a commitment to green molecules without dilution of standards. Partnerships and alliances between industries and governments will play a pivotal role in accelerating adoption.
While challenges remain, the potential of GH far outweighs these hurdles. As countries like India harness their renewable energy strengths and craft supportive policies, GH can redefine industrial growth by aligning sustainability with economic progress. Ultimately, the success of this transition hinges on collaborative efforts across industries, governments, and communities to drive innovation, scale production, and make GH a cornerstone of the clean energy future.
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