Hydrogen energy, humanity's "only ultimate energy"?

Therefore, in the process of large-scale transportation, it must be compressed and stored, so that hydrogen appears in a high-density gaseous or solid, organic form.

According to the different states of hydrogen, hydrogen transport can be divided into gaseous hydrogen transport, liquid hydrogen transport and solid hydrogen transport.

Gaseous hydrogen is usually transported by long tube trailers and pipelines. Liquid hydrogen is usually transported by tanker; Solid hydrogen transport can directly transport hydrogen storage metal.

Technically speaking, the gas-hydrogen trailer is the most important and more mature way of transporting hydrogen in China, which is suitable for short-distance transportation.

Although the transport capacity of liquid hydrogen tank truck is 10 times that of gas hydrogen trailer, the liquefaction process costs more and is more suitable for medium and long distance transport.

According to the forecast of CITIC Securities, by 2050, the cost of liquid hydrogen storage and transportation will be reduced to 6 to 8 yuan /kg when the transportation distance is 500km. With the gradual maturity of low-temperature liquid hydrogen storage technology, the cost of liquid storage and transportation will gradually reduce, and liquid hydrogen tank truck transportation will gradually replace the gas-oxygen trailer.

In addition, pipeline transportation similar to natural gas is also one of the solutions for hydrogen transmission and distribution. And the hydrogen transported by pipeline is in a low pressure state, which is cheaper than the cost of high pressure hydrogen transport. When the transportation distance is 500km, the cost is about 3 to 3.1 yuan /kg.

But don't think that the high cost of hydrogen storage and transportation can be easily solved by pipeline transportation, because existing natural gas pipelines cannot be used directly to transport hydrogen.

Generally, natural gas is transported using steel pipes, and hydrogen molecules will dissolve in steel to produce hydrogen embrittlement, exceeding the strength limit of steel. Therefore, to use pipelines to transport hydrogen, it is necessary to use materials with very low carbon content, and the cost is generally twice that of natural gas pipeline materials.

Natural gas and hydrogen can also be used for mixed transportation, but the proportion of hydrogen is strictly required, not more than 20%. There is also a loss of value in mixing expensive hydrogen with cheap natural gas.

With the increase in demand for long-distance hydrogen transportation, pipeline transportation will become the best choice for long-distance transportation in the future, but the initial investment is huge, the utilization rate of equipment is also low, the liquefied gas pipeline is used to transport hydrogen, and the corrosion and strength changes of the pipeline need to be further studied。

4. Application: Who can hydrogen be used for?

From the current demand structure, the industrial color of hydrogen energy application scenarios is still very strong, and hydrogen is mainly used in ammonia synthesis, petroleum refining and other fields. The proportion of civilian hydrogen is very low, and the largest application scenario that can be imagined at present is hydrogen fuel cell vehicles.

Hydrogen fuel cell vehicles are more convenient and more durable than power battery vehicles, and they have clean and environmental protection characteristics compared with fuel vehicles, but the limitation of the technical level is still "hard" :

First of all, the hydrogen produced from fossil fuels is gray hydrogen, which contains more impurities, so it needs to be further purified before it can be used as a fuel cell raw material, which increases the use cost of hydrogen;

Secondly, although the energy density of hydrogen energy in the liquefied state is higher than that of fuel oil and much higher than that of lithium batteries, hydrogen liquefaction is difficult and costly. Currently, automotive hydrogen is still mainly a gaseous state, requiring extremely high injection pressure and high strength hydrogen storage bottle materials that can prevent hydrogen escape.

In addition, the development of hydrogen fuel cells is still relatively lagging behind, the life of domestic homemade hydrogen fuel cells is short, can only meet thousands of hours of driving, and including membrane electrodes and other materials are heavily dependent on imports;

Finally, hydrogen fuel cell vehicles are mainly commercial vehicles such as logistics vehicles and buses, and the proportion of passenger vehicles is very small, which is mainly due to the network of hydrogen refueling stations is still not popular enough, so the current hydrogen fuel cell vehicles are more suitable for models with fixed routes and certain commercial nature to offset high costs.

Although the cost of passenger cars in the future will drop to a level similar to that of lithium battery cars, the important factor restricting the promotion of passenger cars is that the initial promotion of hydrogen fuel cell vehicles is the car level, the lack of other low-level consumer goods, and the lack of infrastructure support such as hydrogen refueling stations.