Hydrogen Storage (eBook)

A Wide Range of Solutions

Patricia de Rango, Fermin Cuevas (Herausgeber)

eBook Download: EPUB

2025
651 Seiten
Wiley-Iste (Verlag)
978-1-394-40162-8 (ISBN)

Infos

Hydrogen storage plays a central role in the hydrogen energy value chain. Efficient, economical and safe methods are essential to increase the gas' volume density and enable the sector's deployment.

Hydrogen Storage analyzes the various ways of storing hydrogen, whether in a gaseous state in pressurized reservoirs or geological structures, in a liquid state through the formation of ammonia or hydrogen-carrying organic liquids, or in a solid state in hydrogen-containing inorganic compounds such as metal hydrides and regenerable hydrides, or by adsorption into porous materials.

For each method, concepts are presented according to the processes used or the storage materials involved. Their advantages and disadvantages, as well as the main obstacles and challenges to be overcome, are analyzed.

This book provides an overview of the various storage solutions currently available, helping operators to choose the most appropriate method for a given application.

Patricia de Rango is CNRS Researcher at the Institut Néel, France, and co-head of the storage axis of the CNRS hydrogen research federation, FRH2. Her research includes materials for energy, particularly the study of metal hydrides for hydrogen storage. Since October 2024, she has been Coordinator of the PEPR-H2 SOLHYD project.

Fermin Cuevas is CNRS Researcher at ICMPE, France, and co-head of the storage axis of the CNRS hydrogen research federation, FRH2. His research includes intermetallic materials, composites and complex hydrides for solid hydrogen storage. Since November 2024, he has been Director of the CNRS Office in China.

Textauszug

1
Hyperbaric Storage

David CHAPELLE1, Damien HALM2 and Stéphane VILLALONGA3

1Institut FEMTO-ST, CNRS, Université de Franche-Comté, Besançon, France

2Institut Pprime, CNRS, ISAE-ENSMA, Poitiers, France

3CEA Le Ripault, Monts, France

1.1. Compressed hydrogen

Dihydrogen gas (hereafter often reduced to hydrogen), as an energy carrier or even as an energy store, is a central element in many scenarios for our future global energy mix (Espegren et al. 2021; Capurso et al. 2022; Kouckaki-Pencha et al. 2023). Key arguments include its abundance, generally in complex forms, or its high gravimetric energy content of 140 MJ/kg (but its low volumetric content of 10.8 MJ/m3 under normal pressure and temperature conditions) associated with two possible uses: direct combustion or coupling to a fuel cell for electricity generation, or even its potential low environmental impact.

In this chapter, we will discuss the most mature way of storing hydrogen gas, namely, a solution consisting of reducing the volume occupied by dihydrogen molecules in their gaseous form by increasing pressure and confining them in a container. This solution, known as compressed hydrogen, hyperbaric hydrogen storage or high-pressure storage, is particularly interesting if the volume can be reduced sufficiently to achieve a significant gain in volumetric energy density, bearing in mind the overall energy balance. As a preamble to our considerations of these storage solutions, we offer a few general points about the element hydrogen and its gaseous form.

1.1.1. Overview of H2

Hydrogen is the most abundant element in the universe (75% by mass and 92% by number of atoms). On our planet, dihydrogen is not very abundant, accounting for just 0.55 ppm of atmospheric gases. The element’s most common source is water, and it is also present in abundance in all organic matter (the hydrogen atom accounts for 63% of the atoms in the human body).

Table 1.1 lists the main characteristics of hydrogen.

Table 1.1. Main characteristics of hydrogen at atmospheric pressure and 293 K (unless otherwise stated)

Characteristics	Values	Units

Density of liquid hydrogen at 10 K

70.6

gH2/L

Atomic mass

1.0079

U

Molar mass of dihydrogen

2.0159

g/mol

Hydrogen gas density at 20.3 K

1.34

gH2/L

Hydrogen density at 273 K

0.0899

gH2/L

Lower calorific value (LCV)

10.8

kJ/L

Gross calorific value (GCV)

12.8

kJ/L

Specific heat at constant pressure

14.3

kJ/kg.K

Specific heat at constant volume

10.3

kJ/kg.K

Autoignition temperature in air

858

K

Flame temperature in air

2,318

K

Flammability limits in air

4–75

% vol

Ignition energy

0.020

mJ

Gas thermal conductivity

0.1897

W/m.K

Apart from these characteristics, it is also essential to understand or remember that, for a real gas, the number of moles per liter, owing to interactions between molecules, is not a linear function of pressure. It is generally accepted that dihydrogen follows the law of perfect gases up to 100 bar. Beyond this, it is imperative to consider the deviation from this law; thus, the density of H2 is approximately 24 g/L at 350 bar and not 30 g/L and is nearly 40 g/L at 700 bar and not 56 g/L (Figure 1.1).

Figure 1.1. Variation in the mass of one liter of dihydrogen as a function of pressure, compared with the variation for a perfect gas.

Thus, the engineer in charge of developing a hydrogen tank has to find the optimum balance between the operating pressure, which increases the volumetric energy density, and the mechanical strength of the structure, which decreases the gravimetric energy density (increase in mass), bearing in mind that as pressure increases, the relative gain in energy density is reduced. There are many other factors to consider, such as economic, societal and environmental constraints, which will be discussed later in this chapter.

Table 1.2 provides the conversion factors for common hydrogen units.

Table 1.2. Conversion of common H2 units at atmospheric pressure and 293 K

	MJ (LCV)	Nm3	GGE1	kWh

1 kg H2

120

11.112

1

33.33

Table 1.3 compares the energy densities of conventional fuels. The gravimetric energy density of dihydrogen is well above that of conventional fuels, but its use requires a significant reduction in the space occupied, especially if mobile applications are to be considered. It is interesting to draw a parallel with information on solid hydrogen storage. On the basis of 2% storage by mass in a material with a density of 5 kg/L, we obtain a low gravimetric energy density of 2.4 MJ/kg for this storage method and, on the other hand, the most remarkable volumetric energy density of 12 MJ/L (of solid).

Table 1.3. Gravimetric and volumetric energy densities for common fuels (Mazloomi and Gomes 2012)

Worldwide, hydrogen production from 2000–2010 (Ewan and Allen 2005; Ball and Wietschel 2009) was close to 50 million tonnes per year, or nearly 600 billion normal cubic meters2. Most of this production (Figure 1.2) comes from fossil fuels, with almost half from steam reforming of natural gas and a third from refining a portion of crude oil. Other sources include coal gasification (nearly 20%) and water electrolysis (4%). Since 2021, this production has reached almost 100 million tonnes per year, but the share of steam reforming has only increased, exceeding 60% of the total contribution (IEA 2022). This dihydrogen, when it is not simply a waste product, is produced on site for internal consumption. It is used almost exclusively as a reagent in the chemical and oil industries: ammonia synthesis (50%), hydrocarbon refining and desulfurization (37%), and methanol synthesis (12%). Only 1% of production is exploited for its energy potential in aerospace and spacecraft propulsion.

Using hydrogen as an energy carrier requires us to consider the hydrogen energy sector in its entirety, meaning all the structures and infrastructures inherent in its operation. Earlier, we discussed hydrogen production and noted that over 95% of the hydrogen produced in 2005 came from fossil fuels. The hydrogen industry, and the economic effort it requires, should only be supported if it brings progress to our civilizations in terms of sustainable development by producing renewable energy, limiting greenhouse gas emissions and promoting access to energy for as many people as possible.

Figure 1.2. Breakdown of primary energy sources used for hydrogen production (Ewan and Allen 2005)

Figure 1.3 shows the impact of hydrogen production, depending on the energy source, on CO2 production and the cost per kilogram of hydrogen produced. A number of observations can be made:

• The current means of producing hydrogen are also the means that emit the most CO2.
• The cost of producing hydrogen from so-called renewable sources is two to three times greater than that of current solutions, which should be put into perspective by the significant drop in the cost of installing photovoltaic panels over the last 10 years.
• Carbon capture and storage can reduce emissions by a factor of 4, while the cost of hydrogen can be multiplied by 2.

In the absence of significant progress on so-called “renewable” sources, and even with higher CO2 emissions, current means of hydrogen production still have a bright future ahead of them, especially as they will also benefit from progress in CO2 capture and storage.

Figure 1.3. Impacts of the choice of H2 production source (Ewan and Allen 2005) on (a) CO2 production per conversion of 1 GJ of primary energy and (b) the cost per tonne produced

As discussed in the regulatory and standards section below and as demonstrated by the efforts of automobile manufacturers to develop hydrogen-powered car concepts and by the efforts of manufacturers of components such as high-pressure couplings for filling stations, real-world consumer applications are gradually emerging. To illustrate this, Table 1.4 shows a comparison of costs, fuel consumption and range (which has since increased significantly for both electric and hydrogen-powered vehicles), depending on the type of vehicle...

Produkt-Details

• Erscheint lt. Verlag: 19.8.2025
• Reihe/Serie: ISTE Invoiced
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Schlagworte: Adsorption • Energy Storage • Geological Structures • hydrogen-carrying organic liquids • Hydrogen Energy • hydrogen storage • Liquid State • Metal Hydrides • pressurized reservoirs • regenerable hydrides
• ISBN-10: 1-394-40162-0 / 1394401620
• ISBN-13: 978-1-394-40162-8 / 9781394401628