MEMPAPER Q4 / 2025 H2—TOMORROW’S FUEL?

H₂—TOMORROW’S FUEL? CHALLENGES AND SOLUTIONS

INTRODUCTION

Hydrogen is the smallest gaseous molecule and has the formula H₂ (CAS No.: 1333-74-0). It is the lightest element and 16 times lighter than oxygen. At the same time, it is the most common element in the universe, accounting for 75% of the total mass. On Earth, the proportion of hydrogen is significantly lower, mostly bound and present as a compound, e.g., as water. Natural gases such as methane and petroleum are other hydrogen-containing compounds on Earth.

Annual hydrogen production ranges between 95 and 97 million tons. This refers to all types and colors of hydrogen. It includes both gray, non-climate-neutral hydrogen and green, climate-neutral hydrogen, as well as all mixed forms. Gray hydrogen is produced from fossil sources without CO₂ capture, while green hydrogen is produced by electrolysis using electricity from renewable energies.

Overview of hydrogen types:

Term	Definition
Grey hydrogen	Conventionally produced hydrogen from fossil sources without CO₂ capture – not climate neutral.
Blue hydrogen	From natural gas, with CO₂ capture (carbon capture and storage, CCS)
Turquoise hydrogen	Pyrolysis of methane – this produces solid carbon (no CO₂)
Green hydrogen	Electrolysis using electricity from renewable energies

Source: Wasserstofferzeugung und Wasserstoffmarkt – Fraunhofer IKTS

APPLICATIONS

H2 is used in a wide variety of applications, for example:

for material use in the chemical industry for the production of ammonia, primarily for the production of fertilizers,
in refineries for the refinement of crude oil, e.g., desulfurization, in order to comply with environmental protection regulations. The combustion of sulfur-containing fuels produces undesirable sulfur oxide (a contributing factor to acid rain),
as an energy source and energy storage medium. These properties are relevant for promoting a hydrogen economy with the aim of replacing fossil fuels with hydrogen as far as possible.

Many countries have developed a hydrogen strategy or vision based on the goals of energy transition and net zero, which outlines the role of hydrogen in the coming decades. Some examples are Germany, Switzerland, the United Kingdom, Japan, and South Korea.

HYDROGEN ECONOMY

The hydrogen economy involves not only the production of H2, but also its storage, transport, and use as a fuel. The hydrogen market is heavily regulated by laws, ordinances, and standards. ISO standards apply internationally. In addition to these standards, there are relevant standards and country-specific guidelines, laws, and norms.

CHALLENGES

The hydrogen industry is considered a key component of the energy transition—especially for sectors that are difficult to decarbonize, such as industry, shipping, aviation, and heavy-duty transport. Nevertheless, it faces a number of major challenges related to technology, economics, infrastructure, and politics.

One of the first measures taken by countries is to establish the framework conditions for an H2 market. Furthermore, the conditions must be created to enable H2 to be produced efficiently from renewable energies. This is because hydrogen is an energy carrier and not a primary energy source – its production, storage, transport, and conversion require a lot of energy. This raises the question of where the use of H2 makes economic and ecological sense (industry, heavy goods transport, shipping, etc.) and where it does not (heating). Supply and demand, as well as the development of domestic and international hydrogen infrastructure, are further prerequisites for the market to function. One opportunity is that existing natural gas networks and connected storage facilities for H2 could be repurposed after testing.

The framework conditions for the hydrogen economy also require safety measures. Not only with regard to security of supply, but also to the measurement and quality infrastructure. Because hydrogen is volatile, explosive, and light, it is difficult to store and transport. Constant monitoring of facilities is necessary.

SAFE H₂ HANDLING

The infrastructure for establishing a comprehensive hydrogen economy is currently still under development in Europe. However, detecting leaks in the infrastructure must be a high priority from the outset. On the one hand, this is for environmental reasons, as hydrogen leaks mean lost energy and therefore always a financial loss. Furthermore, although hydrogen is not a direct greenhouse gas, it indirectly exacerbates the greenhouse effect. Above all, however, hydrogen has several properties that make leak detection essential:

Highly explosive: Hydrogen is extremely flammable and has a wide explosion range (4–75 vol.% in air). Even small leaks can cause an explosion in closed or poorly ventilated rooms.
Invisible and odorless: Unlike natural gas, hydrogen has no odor and no visible flame, meaning that leaks cannot be detected without special sensors.
Diffusion behavior: Hydrogen is the smallest molecule and diffuses very quickly through materials, seals, or microscopic cracks.

ELECTROCHEMICAL GAS SENSORS FOR H₂ MEASUREMENT

Membrapor, a Swiss manufacturer of electrochemical gas sensors, offers reliable solutions for monitoring H₂. Depending on the application, one or more suitable sensor types are available in different housings and with a nominal range of 1,000 ppm—lower explosive limit (LEL).

Membrapor’s sensors are reliable and robust. They offer the highest sensitivity and detect the target gas even at very low gas concentrations. At the same time, they have low cross-sensitivity, which has a positive effect on the measured values. For users, this means fewer false alarms and lower costs.

The portfolio of H₂ sensors consists of various housings. These include the Vantage, Compact, and Slim product types. Membrapor will be happy to guide you through the selection process.