There are three main ways to use hydrogen energy:
1) internal combustion;
2) conversion to electricity using a fuel cell;
3) nuclear fusion.
The basic principle of a hydrogen internal combustion engine is the same as that of a gasoline or diesel internal combustion engine. The hydrogen internal combustion engine is a slightly modified version of the traditional gasoline internal combustion engine. Hydrogen internal combustion burns hydrogen directly without using other fuels or producing exhaust water vapour.
Hydrogen internal combustion engines do not require any expensive special environment or catalysts to fully do the job – hence there are no problems of excessive costs. Many successfully developed hydrogen internal combustion engines are hybrid, meaning they can use liquid hydrogen or gasoline as fuel.
The hydrogen internal combustion engine thus becomes a good transition product. For example, if you cannot reach your destination after refuelling, but you find a hydrogen refuelling station, you can use hydrogen as fuel. Or you can use liquid hydrogen first and then a regular refuelling station. Therefore, people will not be afraid of using hydrogen-powered vehicles when hydrogen refuelling stations are not yet widespread.
The hydrogen internal combustion engine has a small ignition energy; it is easy to achieve combustion – hence better fuel saving can be achieved under wider working conditions.
The application of hydrogen energy is mainly achieved through fuel cells. The safest and most efficient way to use it is to convert hydrogen energy into electricity through such cells.
The basic principle of hydrogen fuel cell power generation is the reverse reaction of electrolysis of water, hydrogen and oxygen supplied to the cathode and anode, respectively. The hydrogen spreading – after the electrolyte reaction – makes the emitted electrons reach the anode through the cathode by means of an external load.
The main difference between the hydrogen fuel cell and the ordinary battery is that the latter is an energy storage device that stores electrical energy and releases it when needed, while the hydrogen fuel cell is strictly a power generation device, like a power plant.
The same as an electrochemical power generation device that directly converts chemical energy into electrical energy. The use of hydrogen fuel cell to generate electricity, directly converts the combustion chemical energy into electrical energy without combustion.
The energy conversion rate can reach 60% to 80% and has a low pollution rate. The device can be large or small, and it is very flexible. Basically, hydrogen combustion batteries work differently from internal combustion engines: hydrogen combustion batteries generate electricity through chemical reactions to propel cars, while internal combustion engines use heat to drive cars.
Because the fuel cell vehicle does not entail combustion in the process, there is no mechanical loss or corrosion. The electricity generated by the hydrogen combustion battery can be used directly to drive the four wheels of the vehicle, thus leaving out the mechanical transmission device.
The countries that are developing research are aware that the hydrogen combustion engine battery will put an end to pollution. Technology research and development have already successfully produced hydrogen cell vehicles: the cutting-edge car-prucing industries include GM, Ford, Toyota, Mercedes-Benz, BMW and other major international companies.
In the case of nuclear fusion, the combination of hydrogen nuclei (deuterium and tritium) into heavier nuclei (helium) releases huge amounts of energy.
Thermonuclear reactions, or radical changes in atomic nuclei, are currently very promising new energy sources. The hydrogen nuclei involved in the nuclear reaction, such as hydrogen, deuterium, fluorine, lithium, iridium (obtained particularly from meteorites fallen on our planet), etc., obtain the necessary kinetic energy from thermal motion and cause the fusion reaction.
The thermonuclear reaction itself behind the hydrogen bomb explosion, which can produce a large amount of heat in an instant, cannot yet be used for peaceful purposes. Under specific conditions, however, the thermonuclear reaction can achieve a controlled thermonuclear reaction. This is an important aspect for experimental research. The controlled thermonuclear reaction is based on the fusion reactor. Once a fusion reactor is successful, it can provide mankind with the cleanest and most inexhaustible source of energy.
The feasibility of a larger controlled nuclear fusion reactor is tokamak. Tokamak is a toroidal-shaped device that uses a powerful magnetic field to confine plasma. Tokamak is one of several types of magnetic confinement devices developed to produce controlled thermonuclear fusion energy. As of 2021, it is the leading candidate for a fusion reactor.
The name tokamak comes from Russian (toroidal’naja kamera s magnitnymi katuškami: toroidal chamber with magnetic coils). Its magnetic configuration is the result of research conducted in 1950 by Soviet scientists Andrei Dmitrievič Sakharov (1921-1989) and Igor’ Evgen’evič Tamm (1895-1971), although the name dates back more precisely to 1957.
At the centre of tokamak there is a ring-shaped vacuum chamber with coils wound outside. When energized, a huge spiral magnetic field is generated inside the tokamak, which heats the plasma inside to a very high temperature, which achieves the purpose of nuclear fusion.
Energy, resources and environmental problems urgently need hydrogen energy to solve the environmental crisis, but the preparation of hydrogen energy is not yet mature, and most of the research on hydrogen storage materials is still in the exploratory laboratory stage. Hydrogen energy production should also focus on the “biological” production of hydrogen.
Other methods of hydrogen production are unsustainable and do not meet scientific development requirements. Within biological production, microbial production requires an organic combination of genetic engineering and chemical engineering so that existing technology can be fully used to develop hydrogen-producing organisms that meet requirements as soon as possible. Hydrogen production from biomass requires continuous improvement and a vigorous promotion of technology. It is a difficult process.
Hydrogen storage focused on the discovery of new aspects of materials or their preparation is not yet at large-scale industrial level. Considering different hydrogen storage mechanisms, and the material to be used, also needs further study.
Furthermore, each hydrogen storage material has its own advantages and disadvantages, and most storage material properties have the characteristics that relate to adductivity and properties of a single, more commonly known material.
It is therefore believed that efforts should be focused on the development of a composite hydrogen storage material, which integrates the storage advantages of multiple individual materials, along the lines of greater future efforts.