Recently, Elon Musk, CEO of Tesla, once again expressed his dissatisfaction with hydrogen energy. "I may have been asked more than 100 or 200 times about this question, but I also want you to understand that using hydrogen as an energy storage means is the stupidest idea," Musk said in an interview at the financial times auto future Summit on May 10 Later, he also explained to reporters: "hydrogen energy is described by the International Energy Agency as a" multifunctional energy carrier ", which has a variety of applications and can be deployed in industries, transportation and other fields. In 2019, the IEA said that hydrogen is "one of the main options for storing renewable energy, which seems to be expected to be the lowest cost option for storing electricity for days, weeks or even months. However, the current efficiency of obtaining hydrogen through electrolysis is pitifully low. At present, most hydrogen production is based on fossil fuels, which is not an environmentally friendly option." In fact, Musk's explanation is not unreasonable. The difficulties of hydrogen acquisition, storage and energy conversion mentioned by musk are all problems. Is hydrogen energy really as good as Musk's statement? What is the current situation of China's hydrogen energy industry? Can hydrogen energy vehicles still be used? 01 hydrogen energy in dilemma There are two main reasons why hydrogen energy is highly expected. One is that hydrogen energy is a renewable and clean energy. Hydrogen is the most widely distributed element in the universe, accounting for 75% of the mass of the universe. Gaseous hydrogen can be produced from hydrogen containing substances such as water and fossil fuels, and store or release energy through physical and chemical changes. Therefore, it is praised by IEA as "one of the main options for storing renewable energy" and "the cleanest renewable energy". At the same time, it is also regarded by many countries as the key to the energy revolution. Second, the energy density and relative safety of hydrogen energy are higher than other fuels. Its energy density is more than three times that of gasoline; The use efficiency of the device is high, and the energy conversion efficiency of the fuel cell is twice that of the traditional internal combustion engine; The reaction product is water, the emission product is absolutely clean, and there is no pollutant and greenhouse gas emission; The safety is relatively controllable, and the detonation conditions are more stringent than gasoline. But the embarrassment is that the current hydrogen energy does not meet expectations. The first is the problem of hydrogen production. At present, the main ways of hydrogen production include hydrogen production from fossil fuels, photolysis of water and hydrogen production from hydrolyzed water. Among them, the method of hydrogen production from fossil fuels can not get rid of the dependence on traditional energy and will also cause environmental pollution. Hydrogen production by electrolyzing water consumes a lot of electric energy, and the efficiency is only 50-70%; Finally, photolysis of water to produce hydrogen is the most ideal hydrogen production technology in theory. In recent years, research results and demonstration projects of photolysis of water to produce hydrogen in various countries are emerging, but they have not reached the level of large-scale hydrogen production. At present, only 96% of the world's production of hydrogen comes from fossil fuels, accounting for only 4% of the world's production of hydrogen. The second is the price problem faced by hydrogen energy. In the manufacturing process, electricity cost is the main component of the total cost of hydrogen production. According to the preliminary calculation of the current price, under the electricity price of 0.5 yuan / kWh, the cost of hydrogen production from alkaline electrolytic water and PEM electrolytic water is 28 yuan / kg and 37 yuan / kg respectively. At present, the investment cost of building a 35MPa, 500kg / D fixed hydrogenation station is about 15-20 million yuan, and the government subsidy ranges from 3-5 million yuan. According to the current price of hydrogen, about 400 hydrogen fueled vehicles can be injected every day to achieve income and expenditure balance, but the cost of hydrogen can not be reduced to less than 40 yuan / kg at present. Compared with traditional gasoline, hydrogen energy has no cost advantage, And then form a vicious circle. Finally, although China's hydrogen energy industry chain is complete, many technologies have not yet achieved independence. A typical hydrogenation station is composed of hydrogen production system, compression system, storage system, filling system and control system. At present, as the core device for pressurizing and injecting hydrogen source into hydrogen storage system, the core components of compressor still need to be imported, and the hydrogen filling machine and hydrogen storage tank have not been localized. Therefore, even if the hydrogen energy is better, it can not be applied on a large scale. 02 can hydrogen energy vehicles emerge suddenly? In fact, there is another reason why musk diss hydrogen energy didn't say it. That is, musk is the boss of Tesla, the world's largest electric vehicle brand, and hydrogen energy vehicles and electric vehicles are essentially competitive products. The biggest difference between the two is in batteries. Hydrogen energy vehicles use fuel cells, whose structure is more complex than that of common power cells. It includes five core components: vehicle control system, fuel cell stack, auxiliary power supply system, gas supply system, driving motor and control system. Among them, fuel cell stack is the top priority of fuel cell, the core component of fuel cell system and the link with the highest value. It is reported that the stack is the place where the chemical reaction occurs in the fuel cell system. It is composed of multiple single cells stacked in series. Hydrogen and oxygen are respectively connected to the anode and cathode of the stack through a certain proportion, and the chemical reaction generates water and electric energy. The quality of the stack determines the overall power density of the fuel cell system. The single cell is composed of bipolar plate and membrane electrode (catalyst, proton exchange membrane, carbon paper / carbon cloth), sealing gasket, collector plate and end plate. Seals are embedded between several monomers, which are tightened and fastened with screws after being pressed by the front end and rear end plates, so as to form a fuel cell stack. In single cell, the catalytic performance of membrane electrode catalyst, the conductivity of proton exchange membrane, the gas diffusion performance of carbon paper / carbon cloth and the conductivity of bipolar plate are the key factors to determine the power density and utility of single cell; At the same time, the consistency of single battery also determines the stability and reliability of the stack. At present, through independent research and development and technology introduction, domestic stacks are gradually realizing the domestic substitution of fuel cell stacks in recent years. However, the overall performance of foreign stacks is better than that of domestic manufacturers. However, even in Germany and Japan, where fuel cells are the most developed, the production of hydrogen energy vehicles is very small. In China, according to the data released by China Automobile Association, from January to March 2021, 104 and 150 fuel cell vehicles were produced and sold respectively, less than a fraction of electric vehicles. The reason is that hydrogen energy vehicles are still in the primary stage of development, and it will be 10 years later to compete with electric vehicles. (Xinhua News Agency)