What is hydrogen and what are hydrogen applications? There has been a lot of talk about this topic for a few years now. The German Federal Government as well as the EU are relying on this energy carrier to achieve the climate goals that have been set. However, the use of hydrogen is anything but simple and requires detailed planning and clever engineers for implementation. But which hydrogen technologies are available and for which areas can they be used economically? What contribution does DiLiCo engineering make in this context? In the following, an overview is given and the main differences in hydrogen applications are discussed.
What is hydrogen?
Hydrogen is the lightest element in the universe and consists of only one proton and one electron. Hydrogen as a molecule is a gaseous energy carrier, very light and therefore very volatile. This makes hydrogen very difficult to handle. However, hydrogen also has a very high mass-related energy density (33.33 kWh/kg) and is therefore suitable as an energy store. One disadvantage of hydrogen is that its volume-related energy density is very low and therefore large quantities can usually only be stored under very high pressure. Nevertheless, there are various technologies that deal with the application of the molecule hydrogen. Because hydrogen is sufficiently available on the planet. It is found in water or bound in hydrocarbons, but not in pure form. Hydrogen must be obtained from water or hydrocarbons.
What are hydrogen technologies?
Hydrogen technologies are mechanical or chemical applications in which hydrogen is used. A distinction can be made between three types of hydrogen technologies:
- Technologies for hydrogen production
- Technologies for hydrogen use
- Technologies for hydrogen storage
In addition to the three types of hydrogen technologies mentioned, there are also technologies for hydrogen distribution and infrastructure. However, these will not be discussed further here.
Technologies for hydrogen production
Hydrogen is not, like other mineral resources, available in raw form on earth, but must be extracted from water or hydrocarbons by the action of energy. The most widely used technologies for hydrogen production are steam reforming and electrolysis. In steam reforming, hydrogen is split off from hydrocarbons by high temperatures and the addition of steam. However, carbon compounds remain in the process, so that the extraction of hydrogen cannot be carried out without emissions. In electrolysis, water is split into its components by a chemical process using electrical energy. This results in oxygen and hydrogen. If the hydrogen is produced during electrolysis with electricity from renewable energy sources, it is called green hydrogen. The hydrogen can then be stored in various forms. On the corresponding page, we explain which types of electrolysers there are and how they work exactly.
Technologies for hydrogen use
The hydrogen obtained can be converted back into electricity by fuel cells, and the electrical energy obtained can be used to operate electrical loads. The so-called cold combustion is used for this. Inside the fuel cell, the reaction between hydrogen and oxygen is carried out in a controlled manner. This produces an electrical voltage that can be used. The waste product of the generation is pure water. There are no emissions from this form of electricity generation. Depending on where the fuel cell is used, different types of fuel cells are used.
Technologies for hydrogen storage
Since hydrogen is very light and volatile, the storage of the chemical substance is a great challenge. Currently, the most widely used method of hydrogen storage is storage in pressurised storage. This type of storage has a low weight compared to other storage options and can be used well in mobility. Another possibility is storage in metal hydride storage. Here, the hydrogen is stored in cold metal grids and is released again when heated. This type of storage can store large quantities, but the weight of these stores is very high. Furthermore, hydrogen can also be stored at ambient pressure at very low temperatures (-252.8 °C). This is well suited for large volumes such as hydrogen filling stations. Depending on the area of application, each storage tank has its advantages and disadvantages.
What are the hydrogen applications?
Image: Schematic representation of the linking of the electricity, heat and gas sectors through hydrogen technologies.
Hydrogen has long been used in the chemical industry for many manufacturing processes. The interest in hydrogen for storage and generation of electrical energy has only been focused on more strongly in recent years. Above all, the very volatile electricity generated from photovoltaic and wind power plants strengthens the need for flexible energy storage. There are a multitude of possible applications for hydrogen technologies:
- Flexible energy storage of renewable energies
- Hydrogen propulsion for trucks, buses, trains and ships
- Sector coupling
- Uninterruptible power supply
- Combined heat and power generation
- Use of hydrogen in the steel industry
The hydrogen technologies mentioned can all be used in conjunction with each other or individually at different locations and applications.
Flexible energy storage
The energy turnaround, which is currently being promoted both at the European level with the "Green Deal" and at the national level with the national hydrogen strategy, puts the green hydrogen as a flexible energy storage in focus. The volatile energy generation through renewable energies poses a major challenge for the transport of energy. Electricity grids must be expanded and generated electricity must be transported to where it is needed.
In order not to overload the electricity grids, it makes sense to use hydrogen as intermediate storage for electrical energy. The electricity generated from renewable energies is stored by electrolysis in the form of hydrogen and can then be flexibly transported to the places where the electricity is needed. By using fuel cells, the hydrogen can then be converted back into electricity in line with demand.
By using hydrogen applications, the problem of electricity storage can be solved to some extent. One advantage is that the energy can be used flexibly. Here, a transition of energy to other sectors can also take place in so-called sector coupling. However, critics say that due to the many conversion processes, the efficiency and thus the loss of energy is very high and thus inefficient. Nevertheless, it is considered sensible for a wind turbine, for example, to continue generating electricity when it can, even if the electricity cannot be taken off at the moment. This is possible through the use of hydrogen technologies such as electrolysis. The excess electricity is then stored in the form of hydrogen. This approach can contribute to decarbonisation and displaces environmentally harmful fossil fuels.
Hydrogen applications in the mobility sector
In the mobility sector, hydrogen technologies can make a significant contribution to decarbonisation. Their use is not limited to passenger cars. The use in train traffic, trucks or ships brings considerable CO2 savings. In Germany, for example, a large proportion of train lines are not electrified. Currently, diesel vehicles still run on these routes. These can be replaced by hydrogen-powered trains and save large amounts of CO2.
Furthermore, fuel cell technology offers a good opportunity to electrify heavy goods traffic. The problem with the electrification of trucks is that the energy demand for locomotion is very high and thus heavy batteries are needed. The hydrogen, on the other hand, can be stored in light carbon tanks and reduces the weight of the truck while at the same time increasing the range.
Stationary hydrogen applications for energy supply
Stationary hydrogen applications with fuel cells are not as much in the public focus as mobile fuel cell applications. In the stationary sector, however, fuel cells can also achieve a great deal. For example, in building energy supply through cogeneration plants with fuel cells, higher efficiencies can already be achieved than with natural gas engine technologies. Fuel cell technology can significantly reduce emissions in the building energy supply sector.
Most systems are already capable of operating with pure hydrogen. However, since the infrastructure is still lacking here, most plants operate on natural gas basis with steam reforming, which still produces minor CO2 emissions. If green hydrogen were used, the energy production of these plants would be without CO2 emissions. In addition, fuel cells are used for uninterruptible power supply in data centres or for critical infrastructure. Fuel cell systems are also already being used for off-grid systems for the uninterruptible power supply of mobile phone masts, as these are much low-maintenance and hydrogen can be stored much more easily and for longer than diesel, for example.
Hydrogen technologies and the energy transition
The applications mentioned above reduce CO2 emissions in a direct way and thus have a strong impact on our environment. On the part of policy, the change towards hydrogen technologies and a hydrogen economy is required. However, it depends on how the hydrogen is produced and where it is produced. Most of the time, hydrogen is not needed where it can be produced. It must therefore be stored and transported.
All these energy expenditures must be included in the effect chain. With this inclusion, it must be considered exactly where the production and application of hydrogen technologies make sense. The fact that the technology of electrolysis represents an important form of energy storage can no longer be denied. In addition to the recovery of electrical energy through fuel cells, hydrogen can also be transitionally integrated into various other sectors. In this way, a progression of the decarbonisation of the sectors can be promoted and the energy transition can be advanced step by step.
Green hydrogen in the context of energy policy
Through the production and application of green hydrogen, the German Federal Government is striving to meet the set climate targets by 2050. Green hydrogen is only one of many building blocks for achieving the climate goals. The European Union also relies on green hydrogen and wants to make Europe the world market leader in the global hydrogen economy. Central to this is the cost-effective production of green hydrogen. Due to the many and flexible applications of hydrogen, fossil fuels can thus be substituted in many sectors. The sector that currently relies most heavily on hydrogen or electrification is the mobility sector. However, hydrogen can also gradually replace fossil fuels in the stationary sector for building energy in the future and thus bring about a considerable reduction in CO2 up to CO2 neutrality.
Economic efficiency of hydrogen applications
Wasserstoffanwendungen können die Zukunft unserer Energieversorgung wesentlich beeinflussen. Der Grund warum die Technologie noch nicht so verbreitet ist, sind die Kosten der Technologien. Die Wirtschaftlichkeit ist sowohl bei der Elektrolyse als auch bei den Brennstoffzellenanwendungen bisher noch ein großer Faktor, warum potenzielle Interessenten die Investition noch scheuen.Hydrogen applications can significantly influence the future of our energy supply. The reason why the technology is not yet so widespread is the cost of the technologies. The economy of both electrolysis and fuel cell applications is still a big factor why potential interested parties still shy away from the investment.
The government has already contributed a lot to the market ramp-up through subsidies, for example through the KfW Programme 433 in germany to promote stationary fuel cell heating. However, the systems are still more expensive compared to available alternatives. Especially in the stationary sector with electrolysers and fuel cell CHPs, there is the problem that the stacks (cells connected in series) require very high operating hours. These are up to 80,000 hours so that a fuel cell heating system can be operated for over ten years. To achieve these values in the long term, more research is needed.
This is where the products from DiLiCo engineering come in. Through our cell voltage monitoring with DiLiCo cell voltage, faults in the stacks can be detected early and repaired by adjusting the operating parameters. This leads to:
- A longer stack life
- A low failure rate of the equipment
- A higher level of customer satisfaction
Another problem of electrolysers and fuel cells is the efficiency and ageing of the cells. This is already over 40% in some applications. In order to increase the efficiency, developers need insight into the inside of a cell in order to better analyse the reaction behaviour. DiLiCo engineering has also developed product solutions for this to offer developers these possibilities. With DiLiCo current density and DiLiCo current density for baltic qCf you have insight into the inside of a cell where you can view the current density and temperature distribution within the cell. This gives the customer:
- Insights into the ageing of the cell
- Insights into the gas and reaction distribution of the cell
- Possible actions to increase the efficiency of the cell
By using the measurement technology from DiLiCo engineering, added value can already be realised in the development of the stacks, which reduces the costs of the overall systems and increases efficiency and service life. Both contribute to further increasing the economic efficiency of the systems.