Hydrogen – energy carrier of the future
Massive reductions in global greenhouse gas emissions are needed to prevent a global climate collapse. Mankind is still a long way from achieving this at the moment; in fact, we are currently even at a maximum level of CO2 emissions. Roughly half of the world’s CO2 emissions can be attributed to industry and transportation alone. Energy generation in these areas in particular must therefore be converted to clean and resource-saving technologies.
This is where hydrogen comes into play as the energy carrier of the future: Hydrogen has significant potential to contribute to decarbonization. H2, as it is chemically abbreviated, is therefore considered a key technology for a sustainable energy transition – especially in the critical areas of industry and transportation – assuming that H2 is produced green.
What is green hydrogen?
In general, hydrogen does not occur as a pure substance, but rather as part of larger molecular compounds, such as in water (H2O). To be used as an energy carrier, it needs to be dissolved by using energy-intensive chemical processes and brought into a pure state. Hydrogen can be obtained in various ways that are more or less climate-friendly.
- Gray hydrogen is produced with the help of fossil fuels. For example, the so-called steam reforming also releases CO2 in the process.
- Blue hydrogen is produced in the same way as gray hydrogen. However, the CO2 produced is captured in the production process. Around 90 percent of the carbon dioxide can thus later be stored in soils.
- Only green hydrogen is produced without any direct emissions of CO2 or other greenhouse gases. In a process known as electrolysis, water is split using green electricity and decomposed into its two elements, hydrogen and oxygen.
Hydrogen as a sustainable alternative to fossil fuels
In the future, green hydrogen can replace oil, coal or natural gas as a sustainable energy carrier. Hydrogen has the advantage of making green power generated from renewables storable and transportable. This means that spatial and temporal gaps in the energy supply can be bridged.
This is a particularly valuable feature for the transportation and industrial sectors. In heavy-duty transport, hydrogen drive systems have advantages over purely electric drives: They significantly increase the range of trucks. Experts predict that hydrogen will surpass diesel in terms of cost-effectiveness from 2030 on. For aircraft and ships, too, hydrogen propulsion is likely to play an important role.
Green hydrogen will also drive the energy transition in industry. According to the EU’s Renewable Energy Directive REDII, 32 percent of energy consumption must come from renewable sources by 2030. 80 percent of the demand for green hydrogen will come from industry by then. For example, feedstocks such as synthetic fuels, ammonia or methanol can be produced with the help of green hydrogen, as can new raw materials in the steel industry.
Key areas of the green hydrogen value chain
Although an energy supply based on hydrogen is not yet competitive today, this will change. The political willingness to do so is there, and the technologies are on the starting blocks. Voith covers key areas of the hydrogen value chain – from production to transport, storage and use.
Hydrogen production via hydropower
Besides fluctuating types of generation such as wind and solar energy, there is a “hidden champion” among renewable energy sources that is ideally suited for generating green hydrogen: hydropower. It is the absolute leader among sustainable forms of energy production, generating 64 percent of green energy. This proven, predictable and competitively priced technology thus plays an important role in the energy transition.
These advantages can be harnessed to produce green hydrogen. On the one hand, fresh water – the feedstock for H2 production – is available in large quantities directly on site. On the other hand, hydroelectric power plants have an extremely long service life of up to 40 years, until the first modernizations are necessary. But the unrivaled high efficiency of over 90 percent in modern plants and continuous operation also play a key role. Above all, run-of-river power plants, some of which have more than 6,000 full load hours per year, offer the ideal basis for electrolysis plants for hydrogen production at relatively low costs. Voith is a leading hydropower supplier.
Transport via hydrogen pipelines
Pipelines are one way of transporting the hydrogen produced to hydrogen refueling stations or industrial plants. So far, the worldwide network of hydrogen pipelines measures around 4,300 km. In the future, the infrastructure will be further expanded, also through publicly funded projects such as the “European Hydrogen Backbone.” By 2040, up to 40,000 km of pipeline will be laid in a total of 21 countries as part of the European project.
Initially, the pipelines might transport a mixture of hydrogen and natural gas. Gradually, however, pure H2 pipelines will emerge within 20 years. These will be a central component of H2 transport. Voith is using its existing expertise in new drive technologies for hydrogen pipelines.
Storage in high-pressure hydrogen tanks
In order to use hydrogen on board a vehicle, it must be stored in smaller quantities. This is achieved with the help of specially developed gas storage tanks. These must meet high safety standards, as they are filled with the highly flammable hydrogen at up to 700 bar. Particularly in the case of hydrogen vehicles, whether hydrogen fuel cells or hydrogen combustion engines, such tanks must also be able to withstand accidents. Because of these factors, gas storage tanks are one of the most challenging system components in hydrogen vehicles.
Voith Composites is working on the next generation of high-pressure hydrogen tanks for fuel cell vehicles that can meet these requirements: The inner part of the tank is made of plastic. Carbon fiber reinforced plastic (CFRP) is stretched around the inner part using the finite element method (FEM) and winding simulations. This makes the new tanks cheaper, lighter and more resilient.
Utilization by means of hydrogen fuel cells
The electrolysis that previously separated hydrogen and oxygen must be reversed to release energy from hydrogen. The hydrogen from the hydrogen tank reacts with the oxygen in the air to form water as a “clean” waste product. This process occurs in a fuel cell: During the chemical reaction at the anode and cathode, chemical energy is converted into electrical energy.
In continuous operation, the electricity generated is not only fed directly into the drive, but parts are also temporarily buffered in a battery. This offers an advantage in that peak loads during acceleration are covered and braking energy can be stored in the battery at the same time.
Components for the hydrogen-electric powertrain
Regardless of whether the electrical energy is generated by hydrogen fuel cells or comes only from the battery in purely electric vehicles, it must be converted into kinetic energy at the wheel via an electric drive train.
Voith has developed a complete electric driveline for city buses for this (“Voith Electrical Drive System”) that has already been introduced to the market in purely battery-electric vehicles. The driveline for truck applications with the core components traction converter, central electric motor and transmission is currently under development and will be available from 2023 on.
Voith relies on green hydrogen
The topic of hydrogen production and use is of great importance to Voith. That is why the company is continuously expanding its involvement in all relevant areas of the hydrogen value chain.
The points of contact are manifold: Voith experts from the areas of hydropower, drive technology and Voith Composites are working on strategies and concepts to develop innovative ideas into future-proof and marketable technologies in the field of hydrogen utilization. Voith is thus making a vital contribution to the decarbonization of industry.