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international journal of hydrogen energy xxx (xxxx) xxx
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Short Communication
Transition toward emission-free energy systems
by 2050: Potential role of hydrogen
Pawan Kumar Pathak a, Anil Kumar Yadav b,*,
Sanjeevikumar Padmanaban c
School of Automation, Banasthali Vidyapith, Rajasthan, 304022, India
Department of Electrical Engineering, NIT Hamirpur, Hamirpur (HP), 177005, India
Department of Electrical Engineering, Information Technology and Cybernetic, University of South-Eastern Norway,
Porsgrunn, Norway
article info
Article history:
Hydrogen has a potential role in helping the world for obtaining net-zero emission/emis-
Received 31 October 2022
sion-free energy systems by 2050 and restrict global warming by 1.5 C because it can
Received in revised form
subside 80 gigatons (GT) of CO2 by 2050. This causes the utilization of 660 million metric
1 December 2022
tons (MT) of low-carbon hydrogen and renewables up to 2050, almost equal to 22% of global
Accepted 5 December 2022
energy demand. In the coming decades, the need for very high clean hydrogen production
Available online xxx
to fulfill the decarbonization role for net zero emission. About 4.5 to 6.5 terawatts (TW) of
renewable power, about 3e4 TW of electrolysis, 40e280 MT of minimal carbon hydrogen
production reforming capacity, and 1e1.25 GT of CO2 storage infrastructure in a year are
Greenhouse emission
required for supplying 660 MT of end uses. In such circumstances, 15e25% of total
Hydrogen pathway
renewable energy is required for hydrogen till 2050 e a 10X enhancement over the present
Emission-free energy systems
installed capacity (2.8 TW).
Net-zero emission
© 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Energy sectors
One of the malignant impacts of the greenhouse effect is a
constant elevation in the Earth's atmospheric temperature.
Yearly peak CO2 emission is breaking new records due to five
sectors: industry, energy, agriculture, building, and transportation. If we want to limit future warming, we need “deep
and rapid” emission cuts across these sectors. A very adverse
environmental impact can be seen due to the utilization of
fossils and greenhouse emissions. The major global emission
by five sectors: industry, energy, agriculture, building, and
transportation, is depicted in Fig. 1 [1,2]. Hydrogen can obtain
emission-free energy systems via the decarbonization process
[3,4]. Hydrogen has higher specific (energy/unit mass); a very
high temperature is achieved during hydrogen combustion
and can be stored in large quantities [5,6]. Hence, hydrogen is
considered a versatile energy vector that may be utilized in
various hard-to-decarbonize fields where electricity may not
be suitable. To trigger the decarbonized energy system,
hydrogen is essential. It helps integration of renewable-driven
* Corresponding author.
E-mail address: [email protected] (A.K. Yadav).
0360-3199/© 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058
international journal of hydrogen energy xxx (xxxx) xxx
Fig. 1 e Worldwide greenhouse gas emission by sectors
energy because it can provide resilience, energy storage, and
transport a high volume of energy via ships and pipelines [7,8].
It may be obtained from electricity and converted into or used
as chemicals, fuels, and power; hence electricity-driven
hydrogen will reshape and connect current chemical, gas,
power, and fuel markets [9,10]. A special report by International Energy Agency (IEA) on the roadmap for the global energy sector to achieve net zero by 2050 was published in 2021
[10]. Hydrogen production is obtained via renewable sources
such as wind, biomass, solar, algae, geothermal, and traditional non-renewable sources such as coal, natural gas, nuclear and thermochemical processes [11,12].
Various types of hydrogen production with the level of
greenhouse gas footprint are depicted in Fig. 2. A vivid
hydrogen generation scheme with the cost analysis of each
source is demonstrated in Ref. [11]. To obtain emission-free
shipping, a comparative analysis of three critical candidates:
hydrogen, methanol, and ammonia, is performed [13]. A bibliometric assessment with future direction for sustainable energy production via hydrogen electrolyzer is revealed in
Ref. [14]. The case studies are performed from the global literature to benchmark the statical electrolyzer analysis, modes of
operation, outstanding issues, critical challenges, and future
research. Chemical and biological methods (bio-hydrogen
production) as the future of hydrogen energy are briefed in
Ref. [15]. The economic evaluation of bio-hydrogen production
in the view of production, transportation, and storage is also
performed. The results showed that bio-hydrogen might be an
excellent possibility for renewable-based hydrogen production.
Low-gradient combustion has become an alternative scheme to
reduce the carbon footprint when combined with hydrogen as a
blended compound or fuel. Recent enhancement in low
gradient combustion as hydrogen fuel blend is demonstrated in
Ref. [16]. A detailed comparative analysis of renewable
Fig. 2 e Various types of hydrogen production with greenhouse footprint.
Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058
international journal of hydrogen energy xxx (xxxx) xxx
electricity and fossil fuel-driven hydrogen based on cost and
emission is performed in Ref. [17]. According to this literature
[17], various national hydrogen techniques define both
renewable-based and fossil fuels with carbon capture and
storage (CCS) as ‘low-emission’ and/or clean hydrogen. However, the carbon footprint is higher in fossil fuel-driven
hydrogen than in renewable-based hydrogen, as presented in
Fig. 2. In 2020 International Renewable Energy Agency (IREA)
published a report on the cost reduction of green hydrogen to
meet the 1.5 C climate goal by scaling up electrolyzer [18]. In
November 2021, Hydrogen Council (McKinsey & Company)
published a report on hydrogen for net-zero [19]. In this detail,
global hydrogen demand and the pathways to achieve an
emission-free energy system by 2050 are demonstrated.
By 2050, North America, Europe, and China will be the
largest hydrogen markets, with 60% global demand. Hydrogen
is rarely present in its natural condition; it must be obtained
from other materials, causing energy. In the present scenario,
producing low-carbon hydrogen is a very challenging task.
The detailed production methodologies of grey, blue, and
green hydrogen are revealed in Fig. 3. These three forms of
hydrogen are gaining much attention in the present scenario.
The grey hydrogen is made of methane via steam methane
reformation, a carbon-intensive process containing a carbon
footprint of 10 kg CO2/kg H2. The grey hydrogen production
process produces CO2 in the atmosphere, while the production of blue hydrogen captures the CO2. So, these two
hydrogen forms are unsuitable for achieving emission-free
energy systems. Moreover, the production of green hydrogen
is obtained via electrolysis of water and renewable energy;
hence, it contains zero carbon.
✓ Blue and grey hydrogen depends on the supply of fossil
✓ Blue hydrogen depends on CCS technology.
✓ Green hydrogen depends on renewable energy and supply.
✓ Supply of the critical care elements and electrolyzer build
rates are required for green hydrogen.
✓ Hydrogen production via fossil feedstocks causes greenhouse emissions even when CCS technology is used.
✓ Hydrogen produced via electrolysis does not create greenhouse emissions.
Presently, most of the hydrogen is grey (fossil-based), so to
achieve the goal of zero emission by 2050, much focus is
required on low carbon (blue) hydrogen and renewable (green)
hydrogen. By 2050, 20%e40% of the supply, that corresponds to
140 MTe280 MT of hydrogen will be provided by low carbon
hydrogen [10]. In comparison to present grey capacity, the
above-mentioned capacity is around two to three times higher
and will necessitate huge infrastructure for the storage of 1.5
GTe2.5 GT of CO2 a year. Moreover, 60%e80% of the supply that
corresponds to 400 MTe550 MT of hydrogen will be provided by
renewable driven green hydrogen by 2050 [10,18]. For this,
immense power, 4.5 TW to 6.5 TW renewables and electrolysis
capacity of 3 TW to 4 TW will require. For emission-free energy
systems by 2050, hydrogen demand will reach 140 MT by 2030,
of which 75 MT will be clean hydrogen [10]. Moreover, blue and
green hydrogen supply must inflate to help emission-free energy sectors. The full potential of hydrogen may be utilized if
proper action is taken over three areas: trigger demand, enable
access via infrastructure, and close the gap between traditional
and hydrogen decarbonization methods.
Key Features of Hydrogen:
✓ Hydrogen can store very high energy over a long period of
✓ In pipelines, storage of hydrogen can be done via “line
packing,” i.e., a high volume of hydrogen is stored by
boosting the pressure in pipelines.
✓ The energy system's resiliency will be enhanced via end
uses of hydrogen.
Fig. 3 e Green, blue, and grey hydrogen production process.
Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058
international journal of hydrogen energy xxx (xxxx) xxx
✓ It can enable global and regional energy transmission.
✓ Compared to electrical grids, 10 to 20 times more energy
can be transmitted via pipelines.
✓ Hydrogen may be shipped over long distances.
Hydrogen pathways in energy sectors
By 2050, 660 MT of hydrogen will require for the end uses to
achieve the target of an emission-free energy system [10,19].
Sector-wise hydrogen demands in MT are revealed in Fig. 4.
Hydrogen is essential for the decarbonization of industries,
e.g., feedstocks for food, glass, fertilizers, and steel, in form of
synthetic fuels for maritime vessels and aviation, for power
generation, e.g., as backup power, in case of ground mobility
provides fuels for heavy-duty trucks, coaches, passenger vehicles for long range, trains and lastly for high grade (temperature > 400 C) industrial heating [5,6,19].
Rapid acceleration and firm commitment are essential to
achieve emission-free energy systems. It is estimated that
Fig. 4 e Hydrogen demand by sectors: end uses.
75 MT capacity of clean/green hydrogen is required by 2030,
which is an acceptable target [10]. With this amount of clean/
green hydrogen, ammonia refining and methanol-based
25 MT of grey hydrogen, ground mobility based 50 billion liters of diesel, and steel production based 60 MT of coal can be
replaced. The most significant segments for hydrogen's enduse applications by 2050 will probably be feedstock, industrial heating, mobility, and building heating correspond to
90% of the total demand (660 MT) [10,18]. The hydrogen
pathways to achieve emission-free energy systems are
revealed in Fig. 5, and the significant sectors associated with
hydrogen end uses are:
Currently, 19% of global emission is due to mobility, which will
be the most significant segment of hydrogen and use with
285 MT of demand by 2050 [10]. The mobility sector inculcates
maritime, aviation and ground mobility. The most challenging
areas for decarbonization of mobility and uses are containerships and long-range flights, and the combination of biofuels and hydrogen is the unique scalable pathway for the
decarbonization of these areas. Moreover, around 4% of global
emission is produced by aviation and maritime; these are the
long-range and high-power end applications and will partly
depend on hydrogen-driven fuels for decarbonization. To
obtain complete decarbonization in maritime fields, liquid
hydrogen and hydrogen-driven fuels like methanol,
ammonia, or e-methane are the potential green fuels [10]. CO2
captured from direct air or CO2 obtained from biogenic sources in combination with hydrogen will be promising synthetic
fuels (e-kerosene) for aviation and intercontinental flights
[10,18,19]. These two end applications will become essential
consumers of liquid hydrogen and correspond to 110 MT of
hydrogen demand with 13 GT abetment of CO2 by 2050
Fig. 5 e Hydrogen pathways in energy sectors.
Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058
international journal of hydrogen energy xxx (xxxx) xxx
Industrial Heating
Due to the high utilization of natural gas and coal, industrial
heating is one of the significant emission sources. Many
decarbonization schemes are available such as direct electrification, biomass, hydrogen combustion, and post-combustion
carbon storage. Hydrogen has the potential to decarbonize
industrial heat, mainly for high-grade heating applications like
aluminum remelting, glass making, and cement plants. By
2050, these sectors will require 70 MT of hydrogen demand to
achieve emission-free systems, particularly for high-grade industrial heating [10,19].
The steel plant is the world's highest carbon emission industry; around 8% of annual global emissions are due to the
blast furnace process. Very few decarbonization pathways are
available for the steel melting process. Which makes it the
most challenging task for decarbonization and for the complete decarbonization process relies only on hydrogen. For
this purpose, around 35 MT of hydrogen demand by 2050 is
necessary for the decarbonization of steel industries, accounting for the 12 GT emission suppression through 2050.
Power Sector
According to the data available till 2019, the power sector
accounted for 30% of worldwide emissions [10]. The critical
decarbonization pathway is the high penetration of renewable
generation capacity in the power sector. Wind and solar
power are inherently volatile, but the power sector causes
long- and short-term balancing. Hydrogen can play a critical
role for the decarbonization process of 1%e3% of power demand in a completely decarbonize based grid because it may
give the options of seasonal storage, long-duration storage,
and peak shaving and will be crucial for grid stabilization.
Around 65 MT of green hydrogen will require for grid power
generation by 2050 [10].
In order to reduce the carbon footprints of aromatics, the
decarbonization process is very necessary, but the decarbonization of benzene, toluene, and xylene (BTX) production is at
an initial stage. Aromatics production via hydrogen routes like
methanol-to-aromatics, which includes CO2 captured from
the air or biogenic sources with clean hydrogen, is presently in
testing mode and underdeveloped. It is expected that the
decarbonization of aromatics will boost after 2030 when
technology commercialization occurs. Around 40 MT of
hydrogen will require for methanol to aromatics by 2050. BTX
can work as a carbon sink for plastic production (e.g., nylon)
by long-duration storage of captured CO2. The low carbon BTX
may contribute to negative CO2 emission if air-captured CO2
or biogenic CO2 is utilized and the plastic is not burnt.
Building Heating
Around 5% of global emissions produce by heating commercial and residential buildings and are the last hydrogen end
applications to scale due to high infrastructural investment
requirements, as it will cause pipeline-based hydrogen distribution networks. Blending hydrogen in the present natural
gas grid can provide an early step for the entire hydrogenbased pipeline networks. The key advantages of blending
hydrogen in the natural gas grid are: a step toward a carbon
neutral future, a significant reduction in greenhouse gas
footprint, enhancement of the air quality of hydrogen
blended fuel cell electric vehicles by reducing oxide of nitrogen and sulfur dioxide, renewable driven end products to
consumers, etc. Moreover, the significant disadvantages and
challenges of hydrogen blending are integrity management,
limited availability of hydrogen, material durability, leakage,
higher cost, higher risk of asthma, etc. By 2050, 40 MT of
hydrogen will be required for building heating in the US, parts
of China, and Europe, where natural gas is utilized for
building heating [10].
Present Feedstock
Hydrogen can play a critical role in decarbonizing present
feedstock applications such as refining, methanol, and
ammonia. These uses account for 2%e3% of worldwide
emissions presently. For the complete decarbonization of
these sectors by 2050, 105 MT of hydrogen, i.e., around 15% of
total demand, will require [10,18,19].
Boosting hydrogen projects
To achieve emission-free energy systems, private and government sectors have vital roles to play. Scaling through 2030
is very crucial to achieve the emission-free target by 2050.
Around 40 National hydrogen strategies have been declared or
are in developing mode. Due to the war in Ukraine and the
hardening gas and oil markets, the results may be seen in the
hydrogen market globally. For example, Europe is enhancing
its renewable hydrogen target from 5 MTe20 MT by 2030 to
replace the dependency on Russian gas. More than 500 projects have been declared with more than $500 billion globally.
According to Glasgow Financial Alliance, more than $130
trillion of private capital is committed to transforming the
economy for an emission-free future. Around 150 projects
have been appended in the last four to five months. The gigascale projects have doubled in the past year. North America
(67 projects) and Asia -Pacific (121 projects) have seen very
high project growth [10]. To export hydrogen, giga-scale projects have been declared by industry players in Africa, Oceania, Latin America, and the Middle East. These regions are
lower-cost energy resources and attractive and strategically
balanced locations to fulfill the boosting demand of Europe,
Korea, and Japan. Players have declared more than 18 MT of
low carbon and renewable hydrogen by 2030 e an enhancement of 12 MT this year. Moreover, 40 GW of electrolysis
power has been declared since 2020, and this announced capacity has been fivefold higher since 2019 [14]. North America
Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058
international journal of hydrogen energy xxx (xxxx) xxx
What to do now?
Invest in early and rapid pilot projects.
Drive down costs for enabling transition.
Government support and industry adoption.
Bridge the gap between investments.
Finalize the hydrogen business model as soon as possible.
What to do shortly?
Fig. 6 e Hydrogen investments by 2030.
has declared 3.5 MT of hydrogen capacity by 2030; around 85%
will be low-carbon hydrogen. The public and private sectors
need to meet to fulfill and complete these ongoing projects
urgently to achieve an emission-free future.
Boosting capital investments announcement for
Around $160 billion of total direct investments have been seen
globally as the high growth in hydrogen projects by 2030
(revealed in Fig. 6). Most investments are associated with low
carbon and renewable hydrogen production, corresponding to
$95 billion, followed by $45 billion for end uses and $20 billion
for storage, transmission, and distribution [10,19]. The
announced funding's lowest volume involves heating and
power applications, while the steel and mobility sectors account for more than 75% of the announced investments.
Presently, around 100 projects are in the planning stage with a
$64 billion investment, around 126 projects are announced
with $76 billion, and 20 projects are committed with $20 billion
investments [10,19]. To achieve the emission-free pathway by
2050 and 22% of decarbonization of final demand will cause
75 MT of clean hydrogen by 2030. To achieve this target, industries require direct investments of $700 billion in the
hydrogen value chain by 2030. End-use applications will
require $200 billion in investments by 2030 to fulfill aimed
demand for hydrogen plants and new types of equipment
The global hydrogen distribution, shipping, conversion,
pipeline, and refining infrastructure will cause $200 billion in
investments by 2030, with more than half for the hydrogen
mobility infrastructure. The new hydrogen industry and
mobility will require a total of $150 billion in investments
Hydrogen puts forward the probability of moving away from
fossils at the cost of its challenges. A successful transition
toward an emission-free future will probably depend on
hydrogen utilization. If we are planning to limit global
warming to 1.5 C-1.8 C by 2050, the coming decades are
crucial for action e the 2050 ambition of 80 GT CO2 suppression cannot be fulfilled unless the noteworthy and crucial
foundation is laid today.
✓ Enhance carbon abatement budget to meet 2050 emissionfree future.
✓ Address the initial skills gap related to renewable electricity generation.
✓ Wide-scale development for green and blue hydrogen
✓ Widening hydrogen supply chain.
✓ Invest in innovation and research to remove the necessity
for scarce critical components for electrolysis.
Moreover, four short-term opportunities to drive a
hydrogen-based clean future:
1. To scale up the utilization of clean hydrogen by making
industrial ports as nerve centers.
2. Boosting the present infrastructure, like making highrange natural gas pipelines of millions of kilometers.
3. Expand hydrogen in transport via freight, fleets, and
4. Launch the maiden international shipping routes for
hydrogen trade.
Presently, hydrogen is an unprecedented momentum. The
world must not miss this unique chance to secure energy and
an emission-free future. Pivotal momentum has been achieved, and it is time to act now for an emission-free future.
Finally, we can conclude the potential role of hydrogen that
“Green hydrogen e the fuel of the future”.
Declaration of competing interest
The authors declare that they have no known competing
financial interests or personal relationships that could have
appeared to influence the work reported in this paper.
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Please cite this article as: Pathak PK et al., Transition toward emission-free energy systems by 2050: Potential role of hydrogen, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2022.12.058