Oil India Limited (OIL) has taken the first significant step towards Green Hydrogen Economy in India with the commissioning of India’s First 99.999% pure Green Hydrogen pilot plant, with an installed capacity of 10 kg per day at its Jorhat Pump Station in Assam.
What is green hydrogen?
Hydrogen when produced by electrolysis using renewable energy is known as Green Hydrogen which has no carbon footprint.
Types of Hydrogen –
- Hydrogen may be the most common element in nature but it is not found freely. Hydrogen exists only combined with other elements, and has to be extracted from naturally occurring compounds like water (which is a combination of two hydrogen atoms and one oxygen atom). Although hydrogen is a clean molecule, the process of extracting it is energy-intensive.
- The sources and processes by which hydrogen is derived, are categorised by colour tabs. Hydrogen produced from fossil fuels is called grey hydrogen; this constitutes the bulk of the hydrogen produced today.
- Hydrogen generated from fossil fuels with carbon capture and storage options is called blue hydrogen;
- Hydrogen generated entirely from renewable power sources is called green hydrogen.
- In the last process (green hydrogen), electricity generated from renewable energy is used to split water into hydrogen and oxygen.
- If the hydrogen is generated from nuclear energy sources, it is called pink hydrogen.
Significance of ‘Green Hydrogen’ –
- “Green hydrogen” will be a major component of renewable capacity, reducing dependence on fossil fuels.
- Hydrogen is the most abundant element and easily harvested by running a current through water in a process called electrolysis. When hydrogen recombines with oxygen, it generates power with emissions of water. If electrolysis is done with renewable energy, the entire cycle is very low-carbon with less environmental impact than solar or wind.
- It may require less capital equipment imports to create green hydrogen capacity. Apart from use in transportation, hydrogen may be a good storage material for surplus electricity generated from renewables.
- Solar and wind are intermittent; sometimes they don’t generate any power, and sometimes they generate surplus. The surplus can be used to electrolyse hydrogen, which can be stored. This has advantages over conventional lithium-ion batteries, including longer-lasting storage and a much lower carbon footprint.
- The engineering problems associated with 1-1-1 are formidable. There are challenges of scale, challenges in adopting many new technologies, and challenges in working out distribution chains and storage systems.
- Weight for weight, 1 kg of hydrogen has roughly thrice the energy value of 1 kg of diesel. But at normal density, a kg of hydrogen, the lightest of gases, occupies a volume of about 11,000 litres, versus just over a litre per kg of diesel.
- Moreover, hydrogen is highly reactive at room temperature. So storage and distribution require either high compression to store in special tanks, or chilling to below minus 250 degree centigrade to liquefy. Storage and distribution present problems similar but greater than those involved in handling CNG or LPG.
- Creating commercially viable storage and distribution will be a big task. Similar drastic cost reductions have, however, been visible in solar and wind, and with coherent policy support, there is no reason why this is not possible.
- Side by side, one has to assume that fuel-cell technology and storage solutions will develop to a point where hydrogen energy can be used commercially for a variety of purposes.