Hydrogen pipelines can be divided into long distance delivery pipelines and short distance distribution pipelines.
Long-distance pipeline is mainly used for long-distance and large-scale transportation of high-pressure hydrogen between hydrogen production unit and hydrogen station because of its high pressure and large diameter.
The distribution pipeline has low pressure and small diameter, which is mainly used for low and medium pressure hydrogen distribution between hydrogen stations and customers.
The construction cost of hydrogen distribution pipeline is low, but the construction of long distance hydrogen transportation pipeline is difficult and costly. At present, the cost of long distance hydrogen pipeline is about 630,000 USD / km, while the cost for natural gas pipeline is only about 250,000 USD per km, which is about 2.5 times that of natural gas pipelines.
As a way of hydrogen transportation, pipeline transportation has low cost and low energy consumption, which can realize continuous, large-scale and long-distance hydrogen transportation. Hydrogen transportation pipeline has gradually become an important breakthrough for enterprises to solve the problems of hydrogen storage and transportation, and is the inevitable trend of large-scale utilization of hydrogen in the future.
Under large-scale transportation, pipeline transportation has obvious cost advantages. According to the calculation of Guolian Securities, when the transportation distance is 100km, the cost of transporting hydrogen is 1.43 yuan / kg. Under the same transportation distance, the pipeline transportation cost is much lower than high-pressure tube trailer and low temperature liquid hydrogen transportation. Thus, when downstream demand for hydrogen is sufficient to support large-scale hydrogen transportation, transporting hydrogen via pipeline is a reliable way to reduce costs.
Why is hydrogen pipeline transportation developing slowly?
Pipeline transportation of hydrogen is the way to achieve the mass and long distance transport of hydrogen. However, in China, it is not an easy thing to achieve pipeline transportation in hydrogen.
According to the White Paper on Hydrogen Energy and Fuel Cell Industry in China recently released by the China HF Alliance, there are 2,500 kilometers of hydrogen pipelines in the US, 1,569 kilometers in Europe and 100 kilometers in our country.
The total number of hydrogen pipelines in the world is less than 4,500 kilometers, a difference of several order of magnitude compared to oil and gas pipelines. At present, low pressure hydrogen pipeline transportation at home and abroad is still in the initial stage of development.
Cost is a constraint on the development of hydrogen pipelines. Because of its low energy density and easy to produce “hydrogen embrittlement” phenomenon, the pipeline transportation cost of hydrogen is often higher than that of natural gas at the same energy flow rate. Data show that in the United States, the cost of natural gas pipelines is only $125,000 to $500,000 / km, but the cost for hydrogen pipelines is about $300,000 to $1 million / km – twice that.
What is the material of the hydrogen pipe?
Hydrogen is delivered in pipelines made of special materials, such as monel alloy.
Monel alloy has excellent corrosion resistance to reducing media, It has good stability in hydrofluoric acid, alkali, sea water, HS, HSO and HPO, organic acid and many other corrosive media, especially in hydrofluoroacid and alkali solution.
Because hydrogen molecules can get into the lattice of many metals, causing “hydrogen embrittlement,” storage tanks and pipes for hydrogen require special materials and more complex designs.
Hydrogen is not easy to store and transport safely. It is light, elusive, diffuses quickly and needs to liquefy at low temperatures, which can cause valves to clog and create unnecessary pressure.