By Pilar Henríquez and Nathalia Ortíz
Imagine arriving at an intercity bus depot on a
holiday weekend, full of buses coming and going to drop off/look for
passengers; or imagine that you work in a port receiving thousands of trucks to
load/unload containers ... probably what comes to mind is a lot of noise,
polluted air entering your lungs, bad smell caused by combustion, among others.
How different would it be to wait for the bus in a quiet environment or to work
day by day in a port immersed in a space free of contamination. Well, hydrogen
mobility is a technology that will contribute to achieving this vision and now
we explain why it became so relevant in the global challenge to achieve
decarbonization.
Transport Sector and Climate Change
The
greatest challenge facing humanity today is climate change and for that reason
it is a central issue on the political, economic and scientific agenda in the
world. Drastically reducing the use of fossil fuels is one of the main objectives
for the different productive sectors, including the transport sector,
responsible for 24% of direct CO2 emissions from fossil combustion
and within this figure, almost 75% it is generated by on-road transport.
To
change this trend, electric mobility and its different technologies are
today one of the main solutions adopted and promoted internationally. You have
probably already read or seen about a battery electric vehicle, which can
operate thanks to the electricity it stores from the network, does not pollute
and is very quiet. Hydrogen fuel cell technology is another application
associated with electric mobility. Both forms of electromobility are
complementary, where hydrogen vehicles will have greater relevance in the
segments of heavy-duty transport, high energy demand or high range requirements.
In the case of hydrogen fuel cell vehicles, it is required to recharge with pressurized
hydrogen gas and not with electricity from the grid. Now we explain more about
this gas that will help us in the energy transition in the transport sector.
Hydrogen
and its main concepts
Hydrogen
(H2 by its chemical formula) is the most abundant element in the
universe. This molecule has a lot of stored energy per mass unit, but low
energy per volume unit. For example, a kilogram (kg) of hydrogen is equivalent
to 2.5 kg of natural gas in energy content, but that kg of H2
occupies 2.5 times more volume than 2.5 kg of natural gas.
Historically,
H2 has been obtained from fossil sources, such as methane reforming
(use of natural gas) or coal gasification of coal, which is called gray
hydrogen. The processes outlined above emit CO2 into the
atmosphere and when CO2 capture technology is incorporated, then the
gas produced is called blue hydrogen. Currently, around 98% of the H2
consumed worldwide is gray (DoE, 2020), mainly in refineries, heavy industries
such as steel or cement, fertilizer production, among others. However, green
hydrogen became a priority due to its enormous potential to decarbonize
multiple processes and sectors, including the transportation sector.
Green
Hydrogen
The
so-called green hydrogen is produced from renewable sources and does not emit
greenhouse gases. The most massive production process obtains the H2
molecule through water, which is separated into hydrogen and oxygen using
electricity from renewable resources. The technology used in this process is an
electrolyzer, obtaining one kg of H2 for every 12 liters of water,
approximately.
So
why isn't green H2 used more widely if it doesn't pollute? Mainly
because of costs, obtaining green H2 with electrolyzers is intensive
in the use of electricity (60% of the cost of producing green H2,
approximately). However, the greater deployment of the use of renewable
energies and its impact on the reduction of electricity costs, added to the
decrease in the cost of electrolyzers of 80% towards the period 2030-2040
(compared to 2019) and the climate emergency, has captured the attention of
decision makers around the world to push it forward.
Green
hydrogen in mobility or Power-to-Mobility
The
hydrogen produced is stored and can then be applied in different ways, which is
known in the literature as Power-to-X. In particular, the application in the
transport sector is known as Power-to-Mobility and involves different technologies
depending on the mode of transport, being the most commercially developed the hydrogen
fuel cell technology. This device converts hydrogen into electricity
through an electrochemical process in which hydrogen reacts with oxygen to
produce water, generating an electrical current. Currently there are several
modes of transport that already use this technology, including cars, trucks,
urban and intercity buses, trains, boats, and airplanes.
Another
trend in the use of hydrogen in transport is in the transformation of hydrogen
into other compounds, where ammonia (NH3) and synthetic fuels are in
continuous research and development, mainly for maritime and aviation
applications.
Why promote hydrogen mobility?
Using
green hydrogen, a fuel cell vehicle (FCEV) stops emitting 100% of CO2
emissions and pollutants compared to an internal combustion vehicle (gasoline,
diesel or natural gas vehicle), so its use and deployment promotes
zero-emission mobility. In addition to reducing emissions, another relevant
aspect is the energy efficiency of vehicles. Efficiency is related to the
process of transforming the energy stored in the vehicle to movement. In the
case of an internal combustion vehicle, this efficiency is between 30% and 36%,
this means that around 60% of the energy contained in fuels is not used. In
comparison, an FCEV is about two times more efficient than a combustion
vehicle, with an efficiency range between 55 and 60%. That is, in one year of
operation, an FCEV would save around 25 GJ (Giga Joules) of energy, enough to light
1 LED bulb for 56 years, 24 hours a day.
Hydrogen mobility as a complement to battery-powered
vehicles
As we have already mentioned, another technology that
plays a fundamental role in the decarbonization of mobility is battery electric
vehicles (BEVs). As the name suggest, vehicles operate on a battery system and
are powered by electrical energy. BEVs are even more efficient than an FCEV,
with efficiencies of around 95%. However, hydrogen mobility is seen as a
complement to battery mobility in segments where BEVs present drawbacks
according to operational requirements. Specifically, FCEVs have characteristics
that make them an ideal technology for heavy-duty transportation and
long-distance transportation segments. These characteristics are:
·
Greater autonomy: FCEVs generally have greater autonomy compared
to BEVs as hydrogen systems store more energy, allowing them to travel longer
distances on a single charge. This is relevant in segments where daily routes
are extensive, such as heavy cargo transport and intercity buses.
·
Shorter refueling
times: the refueling time
for a battery-powered vehicle can be up to 8 hours, which represents a problem
in segments of intensive use with little availability of time in stopping or
without circulation. In contrast, the charging time for a hydrogen truck is below
than 10 minutes.
·
Greater transport
capacity: a hydrogen truck
propulsion system (including the fuel cell, storage tank and hydrogen) is up to
75% less heavy than a battery powered system. This translates into a higher
payload for the FCEVs as less payload is sacrificed. In addition, if a hydrogen
bus and a battery bus with the same dimensions are compared, the hydrogen bus
would have a higher passenger capacity since the fuel cell system takes up less
space.
Key Messages
·
This is fact, not
fiction. There are
successful hydrogen mobility applications in all modes of transport (on-road,
rail, aviation and maritime). Now it is entering the scaling stage to reduce
costs.
·
The challenge of refueling
stations (or Hydrogen Refuel
Station -HRS), as in battery electric mobility, requires building a network of
refueling points that makes the transition to this energy vector feasible. Public-private
alliances are key for this purpose, where risks are balanced, and political and
regulatory bases are the framework for investment.
·
Human Capital, green hydrogen requires more professionals who
can support the entire value chain (production, storage, dispensing,
applications and associated technologies, etc.). Hydrogen represents an
emerging industry where you can join and be part of the change! Think of
renewable energies 10 years ago, where many sectors indicated that they would
not have the development that we see today in 2021, well at this point we are
now with hydrogen.
·
Disseminate, now that you know what hydrogen mobility is and
that it will be a key piece to decarbonize heavy transport, comment on it in
your environment and help more women become empowered on the subject. The
transport sector has historically been a space for men, but now we can be
protagonists in a new era of sustainable transport.
About the authors
Pilar Henríquez, Chilean, 37 years old, Mechanical Engineer from the
University of Chile, Master in Innovation from the Pontificia Universidad
Católica, Senior Consultant and specialist in Sustainable Mobility, senior
consultant at HINICIO, entrepreneur at @ watermanchile.cl, sporty and mother of
a beautiful girl.
Nathalia Ortiz, Colombian, 24 years old, Chemical and Environmental
Engineer from the Universidad de los Andes, Consultant at HINICIO, with
experience in feasibility and market studies of green hydrogen and sustainable
mobility.
Bibliography
·
(IEA, 2020),
International Energy Agency, Tracking Transport Sector 2020, 2020.
·
(DoE, 2020), US
Department of Energy, Hydrogen Strategy, 2020.
·
(IRENA, 2020), IRENA,
Green Hydrogen Cost Reduction, 2020.
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