Green hydrogen-based energy is a sharp weapon for deep decarbonization in various industries. It is predicted that China's green hydrogen demand will reach 23 million tons, 69 million tons, 91 million tons and 0.12 billion tons respectively in 2030, 2040, 2050 and 2060. Its application is mainly distributed in four major fields: industry, transportation, electricity and construction.

Industrial applications

Industry is currently the largest application field of hydrogen-based energy in China. Hydrogen is an important industrial raw material and has been widely used in industrial fields such as synthetic ammonia, synthetic methanol, petrochemical and metallurgical industries. Under the constraints of the dual-carbon target, the application scale of hydrogen-based energy in industrial fields is expected to grow rapidly.

(1) Synthetic ammonia

Ammonia is currently the largest hydrogen consumption route, and more than 37% of the world's hydrogen is used to produce synthetic ammonia. Ammonia is not only the main raw material of chemical fertilizer, but also an important industrial raw material and intermediate product, which has a wide range of uses in the industrial field. In the chemical fertilizer industry, ammonia is the main raw material for the production of nitrogen fertilizers; in the chemical industry, ammonia can be used to produce organic or inorganic chemical products such as amines, dyes, explosives, synthetic fibers, synthetic resins, etc.; in the electronic industry, high purity Ammonia can be used for large-scale integrated circuit decompression or plasma chemical vapor deposition; in the food industry, ammonia can be used as an alkaline agent, yeast nourishment, food pigment diluent, etc.

The main raw materials for synthetic ammonia are nitrogen and hydrogen. Theoretically, 0.18 tons of hydrogen and 0.82 tons of nitrogen are needed to synthesize 1 ton of ammonia. The source of nitrogen required for the synthesis of ammonia is relatively simple and can generally be obtained by air separation. The source of hydrogen required for ammonia synthesis is more diverse, currently mainly from coal and natural gas preparation of gray hydrogen, in view of the renewable energy electrolysis water produced by green hydrogen with low carbon emissions, high purity characteristics, the future green electricity green hydrogen will become the main source of hydrogen.

(2) Preparation of methanol

Methanol is another big way to use hydrogen. Methanol is a basic organic chemical raw material, which can be used to produce olefins, formaldehyde, dimethyl ether, acetic acid, methyl tert-butyl ether, dimethylformamide, methylamine, methyl chloride, dimethyl terephthalate, methyl methacrylate, synthetic rubber and a series of organic chemical products, which are widely used in chemical industry, light industry, textile, pesticide, medicine, electronics and food. The use of methanol to olefins in modern industry has a strong cost advantage over traditional naphtha to olefins, and has gradually become the main consumer market for methanol, accounting for about 55% of the total demand for methanol.

In the long run, the production of organic chemical products from green methanol is an important means to reduce carbon emissions in the chemical industry. Green methanol refers to methanol synthesized with zero carbon emissions in the production process. At present, there are two main production ways for green methanol: one is to prepare green methanol from biomass, and the other is to prepare green methanol from green electricity. Among them, the technical route of synthesizing methanol from hydrogen by green electricity and carbon dioxide can realize large-scale utilization of carbon dioxide, which is an important technical route for synthesizing green methanol in the future.

(3) Petrochemical industry

Hydrogen is one of the indispensable raw materials in the field of petrochemical industry. Hydrocracking, hydrofining and other processes can improve and change the properties of heavy oil, convert heavy oil into light oil products, effectively improve the refining efficiency of petroleum, and obtain more high value-added products. At present, petrochemical hydrogen mainly relies on fossil energy to produce hydrogen or industrial by-product hydrogen, and there is great potential for green hydrogen to replace it in the future.

(4) Metallurgical industry

Hydrogen can replace carbon as a reducing agent for the metallurgical industry. At present, the mainstream hydrogen metallurgy technology is divided into two ways: blast furnace hydrogen-rich metallurgy and gas-based direct reduction shaft furnace metallurgy: blast furnace hydrogen metallurgy refers to the participation in the metallurgical process by injecting hydrogen or hydrogen-rich gas into the blast furnace. Relevant experiments show that the blast furnace hydrogen-rich reduction metallurgy can reduce carbon emissions to a certain extent by accelerating the reduction of burden, but because this process is based on the traditional blast furnace, there is a limit value for hydrogen injection. It is generally believed that the carbon emission reduction range of hydrogen-rich reduction in blast furnace can reach 10%-20%, and the effect is not significant enough. Gas-based direct reduction shaft furnace metallurgy refers to the use of mixed gas of hydrogen and carbon monoxide as reducing agent to participate in the metallurgical process, and the carbon dioxide emission of gas-based direct reduction shaft furnace metallurgy can be reduced by more than 50%, which is more suitable for hydrogen metallurgy.

Metallurgical industry is a key industry of carbon emissions. According to the annual development report of 2023 double carbon steel, carbon emissions of China's iron and steel industry accounted for more than 60% of the total carbon emissions of the global iron and steel industry in 2023, which is the largest source of carbon emissions of the global iron and steel industry. From the perspective of industry categories, carbon emissions of the iron and steel industry accounted for about 15% of the total carbon emissions of the country, and carbon emissions ranked first in 31 categories of manufacturing industry.

Green hydrogen is regarded as the key to carbon emission reduction in the metallurgical industry. The traditional blast furnace ironmaking is a coal-based smelting method. Carbon emissions account for about 70% of the total emissions of the entire process. Hydrogen can replace carbon in the metallurgical process. The reduction effect, so that the metallurgical industry can get rid of the dependence on coal, and achieve carbon reduction at the source.

Applications in the field of transportation

The clean and green replacement of fossil energy is one of the paths of carbon emission reduction in the transportation field. As a transportation fuel, green hydrogen-based energy can be applied to road transportation, railway transportation, aviation, navigation and other scenarios, which is an effective way to realize low-carbon transformation in the transportation industry in the future.

(1) Road traffic

Highway traffic is the absolute main body of carbon emissions in the field of transportation and the focus of emission reduction. The application of hydrogen-based energy in the field of road transportation mainly includes hydrogen-based energy fuel cells and hydrogen-based energy internal combustion engines.

Hydrogen fuel cells are currently used in road traffic more mature green solutions. The development of hydrogen fuel cell vehicles in China takes the route of commercial vehicles before passenger cars. Hydrogen fuel cell vehicles mainly take passenger cars, heavy trucks, tractors and urban logistics vehicles as the cut-in, and gradually transition to the passenger car field. Compared with the mature pure electric vehicles, hydrogen fuel cell vehicles are suitable for fixed routes, medium and long-distance trunk lines and high load scenarios. According to data from the China Association of Automobile Manufacturers, the sales volume of heavy trucks in my country in 2022 will be 671900, of which the sales volume of hydrogen fuel heavy trucks will be 2382, with a penetration rate of 0.35. It is expected that with the hydrogen energy industry policy, hydrogen fuel cell technology, With the development of supporting facilities such as hydrogen refueling stations, the scale of hydrogen fuel cell vehicles will usher in an opportunity to accelerate development.

Methanol in hydrogen-based energy is the best alternative fuel option in the field of road transportation. Methanol can be used as a gasoline additive or substitute in internal combustion engines, and can also be applied to modified diesel engine vehicles.

Methanol has the following advantages: first, it is liquid under normal temperature and pressure, which is convenient for storage and transportation; second, it has a single composition and relatively clean combustion; third, as an oxygenated fuel, methanol can effectively improve the combustion reaction of the engine and improve the energy conversion efficiency. Compared with gasoline, the average energy conversion efficiency can be increased by more than 20% based on the calorific value. The "14th Five-Year" Industrial Green Development Plan issued by the Ministry of Industry and Information Technology clearly proposes to "promote the promotion of alternative fuel vehicles such as methanol vehicles". At present, China's methanol vehicles have a complete policy license, administrative management license, technical standard license, market access license and operation guarantee license and other related licenses, built a complete product technology chain, industrial chain and supply chain, and built a diversified product system composed of methanol passenger cars, methanol hybrid passenger cars, methanol commercial vehicles, methanol dump trucks, methanol hazardous chemicals transport vehicles, methanol extended range electric vehicles, etc, the methanol automobile industry is about to usher in a historical opportunity for rapid development.

(2) Railway traffic

The application of hydrogen-based energy in the field of railway transportation is mainly to replace the traditional internal combustion engine with hydrogen-based energy fuel cell to provide a new source of power for the train, the advantage of hydrogen-based power train is that it does not need to electrify the existing railway track to achieve the reduction of emissions in the railway transportation industry. European countries such as France, Germany and the United Kingdom have introduced national railway network cleaning and upgrading plans, but in the context of China's high railway gasification rate, the demand for hydrogen-based power trains is relatively limited.

From a technical point of view, the hydrogen-powered train is still in the research and development test stage. In 2022, the world's first pure hydrogen-powered passenger train will officially operate in Germany, with a range of 1000 kilometers and a maximum speed of 140 kilometers per hour. In 2021, China will trial run the first domestic hydrogen fuel cell hybrid train, which can run continuously for 24.5 hours with full hydrogen and the maximum tractable load on straight roads can exceed 5000 tons. In 2022, China built the world's first heavy-haul railway hydrogenation research demonstration station to supply hydrogen fuel to hydrogen-powered trains.

(3) Aviation

Carbon reduction in the aviation industry is difficult to achieve through electrification, and hydrogen-based energy provides a possible carbon reduction solution for the aviation industry. At present, the power of hydrogen energy aircraft mainly includes hydrogen fuel cells, hydrogen-burning engines, etc. Compared with hydrogen fuel cells, the development of hydrogen-burning engines is relatively slow. This is closely related to the differences in many characteristics of hydrogen fuel and aviation kerosene. From fuel to hydrogen, the structural design, especially the design of the combustion chamber, has brought greater challenges.

Hydrogen-powered aircraft may become a carbon reduction solution for short-and medium-distance aviation flights, but in the field of long-distance aviation, it is still necessary to rely on aviation fuel, so the development of green aviation fuel will be the most important measure to achieve the goal of carbon reduction. Green aviation kerosene refers to C8 ~ 15 liquid hydrocarbon fuel from non-fossil resources. According to the life cycle analysis of Global Oil Company of the United States, the greenhouse gas emissions of green aviation oil are 65% ~ 85% less than those of petroleum-based aviation fuel.

Green aviation kerosene can be generated by hydrogenation refining of vegetable oil, waste oil or other high-oil biofuels; it can also be generated by gasification of biomass such as cellulose and lignin to generate syngas, which is then hydrocracked and hydroisomerized after the synthesis process. The research team of Tsinghua University has achieved one-step production of aviation kerosene thermodynamically by designing a process route that points to aromatic-containing ring aviation coal fractions as the target product. At present, a small-scale production experiment of 100 tons/year has been completed. At present, the global green aviation fuel is mainly produced from the green hydrogen refining of bio-oil, and the price is 2700~3100 US dollars/ton, which is about 4 times that of petroleum-based aviation fuel.

Developed countries and regions such as the United States, the United Kingdom, and the European Union have issued top-level strategic plans for the development of green aviation. It is expected that green hydrogen will play an important role in the low-carbon transformation of the aviation industry in the future.

(4) Shipping

The 2023 IMO Ship Greenhouse Gas Emission Reduction Strategy clearly states that by 2030, the carbon dioxide emissions of the international shipping industry will be reduced by more than 30% compared with 2008, and net zero emissions will be achieved around 2050. Hydrogen-based fuels, as an important carbon emission reduction plan in the shipping field, usher in important development opportunities. At present, the application of hydrogen-based fuel in shipping mainly includes two solutions: fuel cell and methanol fuel.

Chinese enterprises and institutions based on domestic hydrogen fuel cells have started the development of hydrogen-powered ships, the current hydrogen-powered ships are mainly used in lakes, inland rivers, offshore scenes, as the main power of small ships or auxiliary power of large ships. In October 2023, my country's first hydrogen fuel cell power demonstration ship "Three Gorges Hydrogen Boat 1" made its maiden voyage, marking a zero breakthrough in the application of hydrogen fuel cell technology in my country's inland ships.

Green methanol as an internationally recognized clean fuel, methanol can achieve a partial or complete replacement of diesel under the low cost of ship modification. At present, Japan, Singapore and other countries have clearly used green methanol as fuel for ship transportation. According to the Braemar estimation of ship brokerage company, by 2030, the global demand for green methanol by Maersk, the international shipping giant, will reach 6 million tons. The application market space of green methanol in the field of ship shipping is huge.

China's ship and ship power manufacturing industry is also actively promoting the manufacture of inland shipping, river-to-sea direct, offshore transportation of methanol fuel-powered ships. In 2017, China Classification Society issued the Guide to Alternative Fuels for Ships, which provides technical standards and application guidelines for methanol as ship power, and research institutions dominated by CSIC are also actively developing core devices for methanol ships such as direct injection methanol engines and methanol fuel filling units.

Power Field Applications

Hydrogen-based energy can be used in the power system "source-network-load-storage" of each link. At the source end, carbon emissions at the power generation end can be reduced by gas-electricity hydrogen doping and coal-electricity ammonia doping. At the network end, hydrogen-based energy can be transported over long distances through pipelines as an effective supplement to UHV power transmission. At the load end, electrolysis of water to produce hydrogen is a flexible load, which can provide flexible response on the demand side for the power system. At the storage end, hydrogen-based energy can be returned to the power system through fuel cells, hydrogen-based energy can be used as a "process energy" with long-term storage capacity, which can realize long-term energy storage across days, months and seasons, which is of great significance to the construction of a new power system.

(1) Gas-electric hydrogen-mixed combustion

Gas-electric hydrogen-mixed combustion refers to the mixing of a certain proportion of hydrogen in natural gas for gas turbine combustion power generation, gas-electric hydrogen-mixed combustion can significantly reduce the total amount of gas-electric greenhouse gas emissions, and reduce the consumption of natural gas as a fossil fuel, is one of the main paths for natural gas power generation to achieve carbon emission reduction in the future.

In recent years, China has continued to actively explore the hydrogen-mixed combustion of gas and electricity. In December 2021, the Jingmen Green Power Plant of the State Council successfully realized the 15% hydrogen-mixed combustion operation of the gas turbine, with the highest hydrogen-mixed ratio of the gas turbine design reaching 30%. In December of the same year, Guangdong Yuedian Daya Bay Integrated Energy Co., Ltd., a subsidiary of Guangdong Energy Group, announced that it would build two 600 MW 9H gas-steam combined cycle heat generation units, the gas turbine unit will use 10% hydrogen mixed with natural gas for combustion. The project will be officially started in 2022 and the first ignition of No. 1 gas turbine will be successfully realized in January 2024. In March 2022, three Siemens SGT5-2000E units used in Zhejiang Petrochemical Gas-Steam Combined Cycle Power Station Project were successfully ignited. This project is the world's first gas-electricity project using natural gas, hydrogen and carbon monoxide as mixed gas.

Major gas turbine manufacturers in the world are actively improving the hydrogen-mixed combustion capacity of gas turbines. At present, GE has more than 100 units with low calorific value hydrogen-containing fuel in operation in the world, with a cumulative operating hours of more than 8 million hours, some of which contain more than 50% hydrogen in fuel, accumulating a lot of practical experience. Judging from different models, GE's E/B-class gas turbine has 100 hydrogen-burning capacity, and its largest and most efficient 9HA-class gas turbine has 50% hydrogen-burning capacity. GE's goal is to achieve 100 hydrogen-burning capacity of 9HA-class gas turbine by 2030. Hydrogen doping from 50% to 100 still has many technical problems in the research and development process, including combustion technology, material technology, control technology, nitrogen oxide control technology four categories.

(2) Ammonia-mixed combustion of coal and electricity

Under the goal of "double carbon", the low-carbon transformation of coal power is imperative. Ammonia doping of coal power is regarded as an effective path of low-carbon transformation of coal power, which has attracted more and more attention. Liquid ammonia has high volumetric energy density, mature large-scale storage and transportation technology, higher octane number of ammonia, more anti-knock, a wide range of applications, and the products of combustion can achieve zero carbon emissions, so ammonia can be used as an ideal fuel to replace coal.

Japan was the first country to attach importance to ammonia blending in coal and electricity. The national strategic innovation and creation plan released by Japan in 2014 covers the research on ammonia-coal mixed combustion technology in thermal power stations with steam boilers as the core. In 2021, the sixth edition of the energy development plan released by the Japanese government mentioned that Japan plans to adopt mixed combustion technology first, such as 30% hydrogen plus 70% natural gas, or 20% ammonia plus 80% pulverized coal, after that, the mixed combustion ratio of ammonia and hydrogen will be gradually increased, and it is planned to achieve 100 percent of ammonia and hydrogen combustion power generation by 2050.

In terms of technology, NEDO (Japan's New Energy Industry Technology Comprehensive Development Agency) commissioned four companies, Tokyo Electric Power Company's wholly-owned subsidiaries JERA, IHI, Marubeni Co., Ltd. and Woodside Energy (Australia's Woodside Energy Company), to carry out the whole industry chain demonstration application of green ammonia blending in large-capacity coal-fired thermal power plants. JERA is responsible for the operation of 1 million kW units in Binan Thermal Power Plant, IHI is responsible for studying the mixed combustion technology of ammonia in boilers, Marubeni Co., Ltd. is responsible for transporting ammonia fuel, and Woodside Energy is responsible for ammonia preparation. At present, JERA is planning to carry out ammonia-coal mixed combustion tests on 1 million kW coal-fired units in Binan Thermal Power Plant, and plans to realize 20% ammonia mixed combustion on Unit 4 of Binan Thermal Power Plant in 2024.

China started late in coal power ammonia doping, but the research and development progress is rapid. On January 24, 2022, the "Coal-fired Boiler Mixed Ammonia Combustion Technology" application project developed by the National Energy Group was successfully put into operation in Yantai, Shandong Province. This technology is the first pilot verification in China to achieve a 35% ammonia mixed combustion ratio in a 40 MW coal-fired boiler, achieving an ammonia burnout rate of 99.99 and no increase in nitrogen oxide emission concentration.

At present, the National Energy Group is carrying out ammonia blending transformation on a 600000-kilowatt unit of Taishan Power Plant in Guangdong Province. After completion, it can reach a blending ratio of up to 20% under various working conditions. In addition to the National Energy Group, Anhui Energy Group and the Energy Research Institute of Hefei Comprehensive National Science Center jointly carried out the research and development of ammonia blending technology for thermal power plants. From April 2022 to June 2023, several engineering verifications were carried out on the 320000 kW subcritical generating unit of Tongling Power Plant, which verified the feasibility of ammonia blending combustion technology for large thermal power units for the first time in China. The maximum ammonia consumption of the project is 21 tons/hour, the blending ratio under 300000 kW output is more than 10%, the blending ratio under 100000 kW output is 35%, the ammonia burnout rate under different working conditions is 99.99, and the nitrogen oxide emission level is equivalent to that before the transformation.

The experimental results of scientific research institutions at home and abroad show that the mixed ammonia combustion of coal-fired boilers can make the pulverized coal and ammonia burn out well, and the nitrogen oxide emissions after combustion do not increase in equal proportion with the increase of the mixed ammonia ratio, and the nitrogen oxide emissions can be significantly reduced by staged combustion.

According to the different ammonia doping proportion, the boiler modification methods will be different. According to the current domestic ammonia doping demonstration projects, the heat exchange structure of the boiler can meet the requirements almost without modification within the range of 0-30% ammonia doping. The modification of the boiler body is mainly focused on the installation of burners, including the coal ammonia doping burner in the main combustion zone and the pure ammonia burner in the reduction zone. In addition to the boiler body, it is also necessary to provide a large ammonia vaporization and supply system, including a large ammonia zone, liquid ammonia pressurization system, liquid ammonia pipeline, liquid ammonia evaporator and buffer tank. When the ammonia doping ratio of the boiler exceeds 30%, compared with pure coal combustion, the radiation heat transfer generated during ammonia-coal mixed combustion is reduced, while the convection heat transfer is increased. Therefore, the heat exchanger capacity at some positions needs to be appropriately increased.

(3) Hydrogen-based energy fuel cells

The hydrogen-based energy source can be converted into electrical energy by the fuel cell and returned to the power system. A fuel cell is a device that directly converts the chemical energy of a fuel into electrical energy. The basic principle is that the fuel enters the anode of the fuel cell and is decomposed into protons and electrons under the action of a catalyst, and the formed protons pass through the membrane to reach the fuel cell cathode., The electrons reach the cathode of the fuel cell through an external circuit to form a current. Depending on the electrolyte, fuel cells can be divided into five categories: including alkaline fuel cells, proton exchange membrane fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, solid oxide fuel cells, etc. Depending on the fuel, hydrogen-based fuel cells can be divided into hydrogen fuel cells, ammonia fuel cells and methanol fuel cells, hydrogen fuel cells are currently developing rapidly. It is estimated that the current pure power generation efficiency of fuel cells using hydrogen-based energy is about 50%, and the comprehensive efficiency through cogeneration can reach more than 85%.

Hydrogen-based fuel cells, either alone or in combination with water electrolysis hydrogen production systems, provide valuable flexibility in regulating resources for power systems. In addition, the hydrogen-based fuel cell system is also suitable for fixed and mobile energy supply scenarios of different scales, such as remote mountainous areas, island border defense, communication base stations, mobile power vehicles, etc., and has a wide range of application prospects.

Application in Construction Field

The energy demand in the construction sector is mainly for heating (space heating) and heating (domestic hot water). Traditional heating and heating mainly rely on the combustion of fossil energy such as coal and natural gas. Using hydrogen-based energy as the main carrier of future building energy can effectively promote low-carbon and green development in the construction sector. The main applications of hydrogen-based energy in the construction field are hydrogen doping in natural gas pipelines and building cogeneration systems.

(1) Hydrogen blending of natural gas pipeline

Hydrogen can be mixed into natural gas in a certain proportion with the help of a more complete domestic natural gas pipeline network for the energy demand of buildings.

At present, many countries in the world have gradually carried out the demonstration of hydrogen doping projects in natural gas pipeline network, among which the highest proportion of hydrogen doping in the demonstration projects in Britain and France has reached 20%. Baotou-Linhe gas transmission pipeline project, the first hydrogen-doped high-pressure gas transmission pipeline project in China, was officially started in March 2023 in Linhe District of Bayannaoer City, with a maximum gas transmission capacity of 1.2 billion standard square/year and a maximum hydrogen mixing ratio of 10%. In April 2023, the hydrogen mixing ratio of the 397-kilometer-long natural gas pipeline demonstration platform in Ningdong, Yinchuan, Ningxia has gradually reached 24%, and has been tested and operated for 100 days, the overall operation is safe and stable, creating a new record for hydrogen transportation in natural gas pipelines at home and abroad.

Demonstration projects and studies at home and abroad show that it is feasible to mix hydrogen between 10% and 20%. According to public data, it is estimated that 10% of global building heating and 8% of building energy will be provided by hydrogen in 2050, which can reduce carbon dioxide emissions by 0.7 billion tons per year.

(2) Building cogeneration system

Hydrogen-based energy can be used to power buildings in the form of fuel cells. The hydrogen-based fuel cell cogeneration system refers to the power supply and heat supply to the building through the energy cascade utilization, and the high-grade energy with high utilization value is used for power generation, while the remaining low-grade energy with lower temperature is used for heating. The comprehensive energy utilization rate of the system can reach 80-90%.

The cogeneration system based on hydrogen-based fuel cells adopts the form of establishing a distributed power generation system in the load center, which can provide heat for civil users such as buildings, communities and industrial users, and bear part of the electricity load, combined with hydrogen doping in natural gas pipelines, can realize the triple supply of electricity, heat and gas. At present, countries represented by Japan, South Korea, and Europe have realized the commercialization of hydrogen fuel cell micro-cogeneration; my country's construction cogeneration is still in the research and development stage. Hebei Province, Guangzhou, Shanghai and other places are planning to promote hydrogen fuel cell cogeneration pilot projects, explore household and commercial hydrogen fuel cell cogeneration models, and help energy conservation and emission reduction in the construction field.