Green hydrogen to play a big role in global decarbonization
Green hydrogen is the most focused subject in the world today, as it is believed that the optimal utilization of green hydrogen as feedstock and energy source could be the most desirable strategy for achieving the target of zero-emission in the next few decades.
In recent months, there have been several announcements and statements from governments, technologists, investors, and large companies all over the world about their commitment to promote the hydrogen industry. Obviously, these entities are of the view that the ultimate solution for the impending global climate crisis is the massive production of hydrogen, which would substitute the use of fossil fuels since hydrogen is the eco-friendly gas that can be used as fuel as well as good feedstock to some extent. At the same time, there is also sceptic who think that hydrogen production technology in an eco-friendly manner at economical cost is yet to be adequately and optimally developed and advocacy of hydrogen industry as the immediate cure to overcome the climate crisis is somewhat premature and is similar to the act of putting the cart before the horse.
Hydrogen can certainly be used as fuel, though some technical issues remain with regard to storage and transportation of hydrogen gas at an acceptable cost level, which can be overcome soon. However, the use of hydrogen as feedstock for the production of derivative products does not have much scope, while substituting the use of fossil fuels with hydrogen. For example, several petrochemicals such as ethylene, propylene, toluene, etc. which are all strong building blocks and are presently produced from petrochemical feedstock such as natural gas, crude oil, or coal, cannot be produced from hydrogen.
Alternate ways of producing hydrogen:
Hydrogen produced by a process that leaves some carbon footprint is not eco-friendly green hydrogen.
Most of the hydrogen today is produced by steam reforming of methane (natural gas) which produces some carbon dioxide.
When the nomenclature brown hydrogen is used, it refers to hydrogen produced from coal. Hydrogen produced from natural gas or crude oil is called grey hydrogen, If grey or brown hydrogen is produced and the carbon dioxide generated is captured and stored safely away, such hydrogen is called blue hydrogen.
Green hydrogen is hydrogen produced by a process that does not emit any greenhouse gases such as carbon dioxide or methane. The best example of green hydrogen is the hydrogen produced by splitting water using electricity from solar plants or wind turbines or hydropower projects.
Most of the hydrogen produced in the world today and several new projects announced for hydrogen production in recent times are based on fossil fuels such as natural gas. In the case of such brown, grey, or blue hydrogen, there is an inherent climate warming component in the feedstock used for hydrogen generation, though hydrogen, by itself, is an eco-friendly product.
Challenges in green hydrogen production:
Green hydrogen should be produced by the electrolysis of water using renewable energy. The major challenge is the cost of production of green hydrogen.
To bring down the cost, the cost of the electrolyzer which splits water has to be reduced. Possibly, the scale of green hydrogen plant capacity can bring down the cost to some extent. Another challenge is the efficiency of the electrolyzers — basically, how much electricity it consumes to produce a kg of hydrogen.
As far as the existing technology is available, the water electrolytic process for the generation of green hydrogen is power intensive and production cost is higher for the green hydrogen than the cost of production of hydrogen presently made by alternate routes. Today, the power requirement for the production of green hydrogen is as high as 55 kWh per kg of hydrogen.
Non-availability of renewable power:
Claiming it to be the production of green hydrogen, several existing and new projects use power generated from fossil fuel for operating the electrolytic process for green hydrogen. This is a counterproductive way.
The power generated from fossil fuel is being used, since the installed capacity for power generation from renewable sources such as hydro, wind, solar are not adequate and are unlikely to be adequate in the future when the large capacity for green hydrogen production would be planned for build-up. Further, the capacity of the utilization of solar and wind power and hydropower plant is much lower than the thermal power plant. Moreover, the generation of solar power, wind power, and hydropower are seasonal and undependable due to possible climate changes and depending on monsoon conditions from time to time.
Under the circumstances, large-scale production of green hydrogen based on electrolysis of water using renewable power sources is unrealistic and wishful thinking.
Case study – How much green hydrogen India needs?
The current consumption of hydrogen in India is about 5.6 million tonnes, but almost all of it comes from the ‘steam methane reforming’ process, based on fossil fuel, which emits the dreaded greenhouse gas carbon dioxide.
Another 1.9 million tonnes of hydrogen is embedded in the methanol and fertilizers that the country imports.
So, today, if India were to replace all the hydrogen in use with green hydrogen, the demand for green hydrogen would be around 7.5 million tonnes per annum.
To produce this much, an electrolyzer capacity of 130-140 GW is required. Roughly, the production of 1 tonne per annum of green hydrogen requires 18 GW of electrolyzer capacity, equivalent to 26 GW of solar power.
Considering that the average capacity utilization of the renewable power industry (hydro, solar, and wind) is only around 20% or even less, it is unrealistic to think that all the hydrogen that India would need could be switched over to green hydrogen.
Alternate process development for green hydrogen:
It is necessary to improve and optimize electrolyzer manufacturing for producing green hydrogen. There is not much to choose from in the immediate future except the age-old alkaline technology.
While electrolysis of water is the prevailing process for the production of green hydrogen, alternate routes are under development.
Alternate technologies are under development such as proton exchange membrane (PEM), anode exchange membrane (AEM), high-temperature reactors (HTR), production from biomass, production using sunshine, etc. All such possible technologies are under development and their commercial suitability is yet to be firmly established.
As such, the above technologies and a few more can best be termed as technology under development, whose date of commercial exploitation, if found feasible, cannot be reasonably predicted at the present time.
The technology development efforts to produce eco-friendly green hydrogen at an economical cost are at the fluid stage at present.
Green hydrogen – Hope or hype?
Several world governments seem to be assuming that the development of cost-effective green hydrogen production technology would happen sooner or later, perhaps, sooner than later.
Obviously, the plans of several governments are based on hope.
However, by not adequately explaining the present limitations of green hydrogen technology and challenges involved in developing the commercially exploitable green hydrogen production technology in the public domain and the world media not discussing the issues involved in-depth, there is a hype today on appropriate green hydrogen technology emerging very very soon.
Under the circumstances, it is strange that the Government of India through its national hydrogen mission has announced specific policy interventions to push for the widespread adoption of green hydrogen in India. The Indian government wants to make it mandatory for industries (first fertilizers and oil refining) to use green hydrogen for a certain specified percentage of their overall energy requirements. Such a requirement is called Green Purchase Obligation (GPO). This strategy of the Government of India amounts to planning in a vacuum, as no one can be sure at present time as to when the green hydrogen would be adequately available in the market.
1. Text in Blue points to additional data on the topic.
2. The views expressed here are those of the author and do not necessarily represent or reflect the views of PGurus.
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