Opportunities, Challenges and Application Prospects of Ammonia Fuel under Carbon Neutrality Purpose
From：
Zhonglin International Group Date：07-26 895 Belong to：Industry Related
In October 2021, the Central Committee of the Communist Party of China and the State Council successively issued top-level design documents such as the "Opinions on Fully Implementing the New Development Concept and Doing a Good Job in Carbon Peaking and Carbon Neutrality" and the "Action Plan for Carbon Peaking before 2030".
After the proposal of the "dual carbon" goal, hydrogen energy has gradually become well-known for its clean, efficient, low-carbon, and flexible characteristics, and is considered an important strategic choice for addressing climate change, replacing fossil fuels, and building a zero-carbon society. In areas such as steel and chemical industry that are difficult to reduce emissions, hydrogen energy will become an important option, and "electrification + electro hydrogenation" will become the main way of energy utilization. Hydrogen power generation is also expected to become an important technical means for providing cross seasonal and long-term electricity regulation in the power system.
However, due to the elemental characteristics of hydrogen itself, there are still serious bottlenecks in the storage and transportation technology of pure hydrogen, and the large-scale and high-quality development of hydrogen energy faces many challenges. In contrast, ammonia has the advantages of easy storage and transportation, zero carbon emissions, and high thermal efficiency. In the context of carbon neutrality, it may become an important carrier for hydrogen energy utilization, and has certain development space in industries, electricity, transportation, and other fields.
The advantage and opportunity of ammonia as an alternative energy
1.1 Features and advantages of ammonia
Ammonia (NH3) is a nitrogen hydrogen compound that, due to its unique physical and chemical properties, has the advantages of easy storage and transportation, zero carbon emissions, and high thermal efficiency. Under the background of carbon neutrality, it will become an important hydrogen-based fuel for hydrogen energy utilization. At present, ammonia is mainly used to produce nitric acid, fertilizers, explosives, and refrigerants. It is one of the most abundant inorganic compounds in the world, with mature technology and complete industry, and has the basic conditions for promotion and application.
(I) Physical features of ammonia
Ammonia is a colorless gas at room temperature with a strong irritating odor. Once a leak occurs, it is easy to detect and promptly remedy, and only becomes lethal when its concentration reaches 1000 times the detectable concentration. Under standard conditions, the density of ammonia is 0.771g/L, which is lighter than air. It spreads quickly after leakage and does not accumulate. Therefore, ammonia has high safety as a fuel. Ammonia leaked into the atmosphere can also participate in natural circulation and react with other substances or be absorbed by plants after moving with rain and snow
Compared to the widely studied pure hydrogen, ammonia has the greatest advantage of being easy to liquefy, store, and transport. Ammonia can be liquefied at -33 ℃ under normal pressure or by pressurizing it to 9 atmospheres at room temperature, while hydrogen needs to be cooled down to -253 ℃ under normal pressure to liquefy, and it cannot be liquefied above -240 ℃. Therefore, storing ammonia only requires ordinary liquefied gas cylinders, while storing hydrogen requires special materials. At present, the main challenge facing the development of hydrogen energy lies in the storage and transportation of pure hydrogen, and the bottleneck of large-scale and long-distance storage and transportation technology is difficult to break through in a short period of time. Therefore, the easy storage and transportation characteristics of ammonia provide a new technological route for the development of hydrogen-based fuels.
(II) Chemical features of ammonia
Ammonia combustion only generates nitrogen and two environmentally friendly products, without producing carbon dioxide, making it a zero-carbon energy source that can effectively reduce the emissions of carbon oxides and sulfur oxides generated by fossil fuel combustion.
Ammonia can not only be directly burned in internal combustion engines to provide power, but can also be used in fuel cells such as alkaline and solid oxides. The energy density of liquid ammonia is higher, more than 1.5 times that of liquid hydrogen and 9 times that of lithium-ion batteries. Compared with gasoline, the combustion value of ammonia is average, but the octane number is high, which can greatly increase the compression ratio of the internal combustion engine to improve output power. Therefore, the thermal efficiency of ammonia internal combustion engines is high, up to 50%~60%, which is about twice that of ordinary gasoline internal combustion engines.
(III) Industrial system of ammonia
In industry, ammonia is usually synthesized using nitrogen and hydrogen under high pressure, high temperature, and catalyst action. The synthetic ammonia industry was formed in the early 20th century and has a history of more than 100 years. The technology is very mature and has become a system in various aspects such as ammonia production, storage, and transportation. Compared with the technology route of "synthesizing methanol from hydrogen and carbon dioxide", which is also at the forefront of research and development, the technology and application conditions of "synthesizing ammonia from hydrogen and nitrogen" are much more mature. Therefore, the promotion and application of ammonia fuel has a good industrial foundation. At present, China's synthetic ammonia industry has entered a stage of transformation and upgrading development, with many large-scale synthetic ammonia sites built. A large number of enterprises with high technological level and large production scale have emerged, such as Yuntianhua, Hubei Yihua, and Hualu Hengsheng. The annual production of synthetic ammonia in China is close to 50 million tons.
1.2 Ammonia fuel’s prospect
Under the vision of "carbon peaking and carbon neutrality", ammonia, as a zero-carbon energy source, has a wide range of applications and will provide new choices for sectors such as electricity and transportation to achieve decarbonization.
(I) Power generation field
With the large-scale development of new energy sources such as wind power and photovoltaic power generation, the volatility and uncertainty of power supply are increasing. It is urgent to develop stable and reliable new power sources to ensure the safe and stable operation of the power system. Ammonia has good combustion performance, is easy to liquefy and store, and has good fuel supply guarantee ability. Therefore, ammonia fuel power generation can be used as a clean zero carbon power generation technology, providing a dispatchable, adjustable, and controllable electricity quantity support for the power system, similar to traditional thermal power. Although there are significant differences in combustion characteristics, composition of combustion products, and radiation characteristics between ammonia fuel and coal, natural gas, and other fuels, there is a risk of increasing NOx emissions during mixed or pure ammonia combustion. However, effective regulation can be achieved through combustion classification, combustion organization optimization, and other methods.
In the future, the large-scale development of new energy will further promote the zero carbonization of synthetic ammonia preparation. During periods of abundant new energy output or low load, the "green hydrogen" produced by electrolysis of water is used to synthesize ammonia fuel, which is then liquefied and stored; When the output of new energy is insufficient or the load is peak, using stored ammonia fuel for power generation can meet electricity demand and alleviate power supply shortages. Although there may be some energy loss throughout the entire process, there will be no carbon emissions generated. Therefore, the "electricity hydrogen ammonia electricity" system is expected to become one of the important storage and dispatch modes for the construction of new power systems.
(II) Transportation field
The International Maritime Organization adopted a preliminary greenhouse gas reduction strategy in 2018, proposing to reduce global maritime carbon emissions by at least 40% by 2030 compared to 2008, and striving to reduce them by 70% by 2050. To achieve carbon reduction and decarbonization in the shipping industry, replacing fossil fuels with clean fuels is the most promising technological means. Ocean going vessels have large deadweight tonnage, long voyages, low frequency of berthing, and relatively inconvenient fuel refueling, requiring the use of high energy density fuels and high-power power devices. Among the highly regarded zero carbon energy sources, ammonia powered ships have an energy density 50% higher than liquid hydrogen, and can utilize existing ammonia supply chains and infrastructure. They have good prospects for promotion and application in the field of long-distance navigation of large ships such as container ships.
In addition, ammonia fuel also has certain application scenarios in road transportation. Amino fuel cell vehicles, trucks, and buses not only have high efficiency and no emissions, but also have advantages such as strong endurance and fast replenishment time. By utilizing existing fuel cell technologies, ammonia fuel can achieve a power density similar to hydrogen fuel at the same temperature, and is considered an ideal fuel that can replace pure hydrogen for fuel cells.
Current issues and challenges of ammonia fuel
2.1 Safety issue
Ammonia is toxic and corrosive, posing a safety hazard. According to the Classification of Occupational Exposure to Toxic Substances, ammonia gas belongs to Class IV mild hazard gas. When exposed to an environment containing a certain concentration of ammonia gas, wet skin, mucous membranes, and eyes may be invaded by ammonia gas, which may lead to poisoning accidents, causing severe cough, bronchospasm, acute pulmonary edema, and even blindness and suffocation death. Ammonia also poses an explosion hazard. When the concentration of ammonia in the air mixture reaches 16%~25%, it can cause an explosion when exposed to an open flame. It belongs to the Class B fire hazard gas specified in the Fire Protection Design Code for Petrochemical Enterprises. In addition, liquid ammonia is highly prone to gasification, and there is also a risk of physical explosion in ammonia storage tanks. In the process of ammonia production and storage, if there is a leak, safety accidents may occur.
2.2 Environmental issue
Compared with other fuels, ammonia has a slower combustion rate and is still difficult to apply in "fast response" scenarios. At present, the relevant technology of ammonia combustion is not yet mature. When ammonia combustion is not sufficient, the reaction process will produce a large amount of nitrogen oxides (NOx), which may cause air pollution such as acid rain, ozone holes, photochemical smoke, and other environmental problems.
2.3 Economical issue
At present, more than 80% of synthetic ammonia in China is produced by coal gasification to produce hydrogen gas, which is then processed and synthesized. The main raw material for synthetic ammonia is still "gray hydrogen", and its production is a high carbon process, which will emit a large amount of carbon dioxide.
With the development of renewable energy hydrogen production technology, "green hydrogen" has provided the possibility for the synthesis of "green ammonia". However, the current cost of renewable energy generation, electrolytic water hydrogen production systems, etc. is relatively high, and "green hydrogen" and synthesized "green ammonia" are still relatively expensive. According to pilot project data, the cost of "green ammonia" is more than 50% higher than coal to synthetic ammonia, and "green ammonia" is not economically feasible in the short term.
The Enlightenment of "Global Ammonia Economy" for China
With the acceleration of global green and low-carbon development, many countries have shown great interest in promoting the application of ammonia and actively layout ammonia? The hydrogen industry, with a focus on ammonia gas turbines, ammonia fuel powered ships, and ammonia? Research on hydrogen transportation and other aspects also provides new ideas and directions for China to achieve carbon peak and carbon neutrality.
3.1 Current situation of ammonia industry
(I) Power generated by ammonia fuel
Under the vision of carbon neutrality, promoting the co combustion or pure combustion of low-carbon fuels such as liquid ammonia in thermal power units is an important technical direction for reducing pollution and carbon emissions in the power generation field. At present, some countries represented by Japan are exploring the development of ammonia based thermal power generation technology to accelerate the decarbonization process of the power sector. Among them, Japanese laboratories and engineering companies have tested and developed small-scale ammonia gas turbines of 50-2000kW; Mitsubishi Heavy Industries is developing a 40MW ammonia gas turbine, which will use 100% ammonia for power generation and combine selective catalytic reduction with new combustion technologies to reduce nitrogen oxides produced by incomplete ammonia combustion. This technology can be used for industrial applications or power plants on remote islands, and Japan plans to achieve commercial application by 2025. In June 2021, GE Power Company in the United States also announced the signing of a memorandum of understanding with Japan's Ishikawa Island Corporation (IHI) to jointly develop an ammonia gas turbine roadmap.
(II) Ships powered by ammonia fuel
In October 2020, the ammonia fuel powered ultra large liquefied gas transport ship developed by China Jiangnan Shipbuilding Group was awarded a principal recognition certificate by Lloyd's Register of Shipping in the UK. In March 2021, the 40000 m3 medium-sized liquefied gas carrier powered by ammonia fuel developed by Jiangnan Shipbuilding Group once again received the principal recognition certificate issued by Lloyd's Register of Shipping in the UK, effectively proving the feasibility of ammonia as a shipping fuel and an important milestone in the shipping industry's use of alternative fuels to promote zero carbon emissions.
South Korean shipbuilding companies are also committed to developing ammonia fuel propulsion ships and seizing the high ground of green power energy technology. In July 2020, the ammonia powered intermediate range refined oil tanker designed by Hyundai Weipu Shipbuilding received a principal recognition certificate from Lloyd's Register of Shipping in the UK, with a carrying capacity of 50000 tons. It is expected to achieve commercial operation by 2025. In January 2021, the Korean Classification Society released a research report on ammonia fuel powered ships, elaborating on the production and use of ammonia, economic benefits, safety characteristics of treatment facilities, ammonia fuel cells, and internal combustion engines.
European countries such as Norway and Finland have very strict environmental requirements, and many ports plan to implement zero emissions. They also plan to start using ships powered by ammonia fuel in the coming years. Wartsila, a Finnish marine engine manufacturer, Eidesvik, a Norwegian marine engineering ship owner, and Equinor, a Norwegian oil company, are cooperating to develop a zero-emission large ship powered by ammonia fuel cells that can complete long-distance navigation. It is expected that the ship will be launched as early as 2024, when it will become the first commercial ammonia powered ship sailing on the high seas.
(III) Ammonia-hydrogen transportation
Ammonia can not only serve as a fuel to provide power, but may also become an important carrier for large-scale hydrogen transportation in the future. On the one hand, compared with hydrogen, ammonia is highly prone to liquefaction, and the difficulty of transporting liquid ammonia is greatly reduced; On the other hand, the volumetric hydrogen storage density in liquid ammonia hydrogen storage is 1.7 times that of liquid hydrogen, and it is also much higher than the current mainstream high-pressure long tube trailer storage and transportation of hydrogen.
Based on the ammonia hydrogen transportation mode, ammonia is considered a key carrier for promoting the export of renewable energy. It has obvious advantages in large-scale "green hydrogen" export projects and has become an important direction for countries such as Japan, Australia, and Singapore to actively layout. In 2018, the Australian Renewable Energy Agency announced an investment of $20 million to support renewable energy exports, including renewable energy export technology using ammonia as a carrier. The renewable energy roadmap released by the Japanese Ministry of Economy, Trade and Industry shows that after 2030, Japan may import $10-20 billion of hydrogen annually, which will also generate a large demand for ammonia hydrogen transportation market.
3.2 Enlightenment for China
With the gradual replacement of fossil fuels, ammonia may become an important component of global energy trade due to its convenient transportation. While countries around the world are actively researching and laying out the "ammonia economy," China should also actively research new technologies such as ammonia gas turbines, power ships, fuel cells, and ammonia hydrogen transportation, and strive to promote disruptive technological innovation in the integration of zero carbon energy and ammonia hydrogen. Based on the development of China's hydrogen energy industry, timely layout of the "green ammonia" industry, and promote the pilot demonstration and promotion application of ammonia fuel.
Of course, ammonia fuel is an option for zero carbon alternative energy, but it is not the only solution. Whether it is synthesizing ammonia from hydrogen and nitrogen or converting ammonia into hydrogen, there will be a certain amount of energy loss, and the large-scale application of ammonia fuel also faces great challenges. To achieve the goal of carbon neutrality, various fields need to conduct research and exploration from multiple perspectives and directions based on actual energy demand and technological development prospects, and ultimately choose an economically feasible zero carbon decarbonization technology route.
Conclusion
Synthetic ammonia is one of the important products in traditional chemical industry, with the characteristics of wide application, mature technology, and complete industry. Under the background of carbon peak and carbon neutrality, ammonia fuel can become an important alternative to fossil fuels due to its advantages of zero carbon emissions, convenient storage and transportation, and high thermal efficiency. It has broad application prospects in power generation, transportation, and hydrogen storage. Although ammonia still faces many challenges in terms of safety, environmental protection, and economy as an alternative energy source, "green ammonia" provides a new path to achieve zero carbon decarbonization. Against the backdrop of the high enthusiasm of countries around the world to layout the "ammonia economy", China should also seize the historical opportunity of low-carbon energy transformation and development, actively carry out key technology research and innovation such as ammonia blending/pure ammonia combustion and power ships, Guide suitable regions to layout "ammonia hydrogen" demonstration projects in combination with advantageous industries, coordinate the integrated development of synthetic ammonia industry, renewable energy, and hydrogen energy industry, and promote the substitution of low-carbon ammonia fuel for fossil energy in areas such as electricity and navigation that are difficult to reduce emissions.
After the proposal of the "dual carbon" goal, hydrogen energy has gradually become well-known for its clean, efficient, low-carbon, and flexible characteristics, and is considered an important strategic choice for addressing climate change, replacing fossil fuels, and building a zero-carbon society. In areas such as steel and chemical industry that are difficult to reduce emissions, hydrogen energy will become an important option, and "electrification + electro hydrogenation" will become the main way of energy utilization. Hydrogen power generation is also expected to become an important technical means for providing cross seasonal and long-term electricity regulation in the power system.
However, due to the elemental characteristics of hydrogen itself, there are still serious bottlenecks in the storage and transportation technology of pure hydrogen, and the large-scale and high-quality development of hydrogen energy faces many challenges. In contrast, ammonia has the advantages of easy storage and transportation, zero carbon emissions, and high thermal efficiency. In the context of carbon neutrality, it may become an important carrier for hydrogen energy utilization, and has certain development space in industries, electricity, transportation, and other fields.
The advantage and opportunity of ammonia as an alternative energy
1.1 Features and advantages of ammonia
Ammonia (NH3) is a nitrogen hydrogen compound that, due to its unique physical and chemical properties, has the advantages of easy storage and transportation, zero carbon emissions, and high thermal efficiency. Under the background of carbon neutrality, it will become an important hydrogen-based fuel for hydrogen energy utilization. At present, ammonia is mainly used to produce nitric acid, fertilizers, explosives, and refrigerants. It is one of the most abundant inorganic compounds in the world, with mature technology and complete industry, and has the basic conditions for promotion and application.
(I) Physical features of ammonia
Ammonia is a colorless gas at room temperature with a strong irritating odor. Once a leak occurs, it is easy to detect and promptly remedy, and only becomes lethal when its concentration reaches 1000 times the detectable concentration. Under standard conditions, the density of ammonia is 0.771g/L, which is lighter than air. It spreads quickly after leakage and does not accumulate. Therefore, ammonia has high safety as a fuel. Ammonia leaked into the atmosphere can also participate in natural circulation and react with other substances or be absorbed by plants after moving with rain and snow
Compared to the widely studied pure hydrogen, ammonia has the greatest advantage of being easy to liquefy, store, and transport. Ammonia can be liquefied at -33 ℃ under normal pressure or by pressurizing it to 9 atmospheres at room temperature, while hydrogen needs to be cooled down to -253 ℃ under normal pressure to liquefy, and it cannot be liquefied above -240 ℃. Therefore, storing ammonia only requires ordinary liquefied gas cylinders, while storing hydrogen requires special materials. At present, the main challenge facing the development of hydrogen energy lies in the storage and transportation of pure hydrogen, and the bottleneck of large-scale and long-distance storage and transportation technology is difficult to break through in a short period of time. Therefore, the easy storage and transportation characteristics of ammonia provide a new technological route for the development of hydrogen-based fuels.
(II) Chemical features of ammonia
Ammonia combustion only generates nitrogen and two environmentally friendly products, without producing carbon dioxide, making it a zero-carbon energy source that can effectively reduce the emissions of carbon oxides and sulfur oxides generated by fossil fuel combustion.
Ammonia can not only be directly burned in internal combustion engines to provide power, but can also be used in fuel cells such as alkaline and solid oxides. The energy density of liquid ammonia is higher, more than 1.5 times that of liquid hydrogen and 9 times that of lithium-ion batteries. Compared with gasoline, the combustion value of ammonia is average, but the octane number is high, which can greatly increase the compression ratio of the internal combustion engine to improve output power. Therefore, the thermal efficiency of ammonia internal combustion engines is high, up to 50%~60%, which is about twice that of ordinary gasoline internal combustion engines.
(III) Industrial system of ammonia
In industry, ammonia is usually synthesized using nitrogen and hydrogen under high pressure, high temperature, and catalyst action. The synthetic ammonia industry was formed in the early 20th century and has a history of more than 100 years. The technology is very mature and has become a system in various aspects such as ammonia production, storage, and transportation. Compared with the technology route of "synthesizing methanol from hydrogen and carbon dioxide", which is also at the forefront of research and development, the technology and application conditions of "synthesizing ammonia from hydrogen and nitrogen" are much more mature. Therefore, the promotion and application of ammonia fuel has a good industrial foundation. At present, China's synthetic ammonia industry has entered a stage of transformation and upgrading development, with many large-scale synthetic ammonia sites built. A large number of enterprises with high technological level and large production scale have emerged, such as Yuntianhua, Hubei Yihua, and Hualu Hengsheng. The annual production of synthetic ammonia in China is close to 50 million tons.
1.2 Ammonia fuel’s prospect
Under the vision of "carbon peaking and carbon neutrality", ammonia, as a zero-carbon energy source, has a wide range of applications and will provide new choices for sectors such as electricity and transportation to achieve decarbonization.
(I) Power generation field
With the large-scale development of new energy sources such as wind power and photovoltaic power generation, the volatility and uncertainty of power supply are increasing. It is urgent to develop stable and reliable new power sources to ensure the safe and stable operation of the power system. Ammonia has good combustion performance, is easy to liquefy and store, and has good fuel supply guarantee ability. Therefore, ammonia fuel power generation can be used as a clean zero carbon power generation technology, providing a dispatchable, adjustable, and controllable electricity quantity support for the power system, similar to traditional thermal power. Although there are significant differences in combustion characteristics, composition of combustion products, and radiation characteristics between ammonia fuel and coal, natural gas, and other fuels, there is a risk of increasing NOx emissions during mixed or pure ammonia combustion. However, effective regulation can be achieved through combustion classification, combustion organization optimization, and other methods.
In the future, the large-scale development of new energy will further promote the zero carbonization of synthetic ammonia preparation. During periods of abundant new energy output or low load, the "green hydrogen" produced by electrolysis of water is used to synthesize ammonia fuel, which is then liquefied and stored; When the output of new energy is insufficient or the load is peak, using stored ammonia fuel for power generation can meet electricity demand and alleviate power supply shortages. Although there may be some energy loss throughout the entire process, there will be no carbon emissions generated. Therefore, the "electricity hydrogen ammonia electricity" system is expected to become one of the important storage and dispatch modes for the construction of new power systems.
(II) Transportation field
The International Maritime Organization adopted a preliminary greenhouse gas reduction strategy in 2018, proposing to reduce global maritime carbon emissions by at least 40% by 2030 compared to 2008, and striving to reduce them by 70% by 2050. To achieve carbon reduction and decarbonization in the shipping industry, replacing fossil fuels with clean fuels is the most promising technological means. Ocean going vessels have large deadweight tonnage, long voyages, low frequency of berthing, and relatively inconvenient fuel refueling, requiring the use of high energy density fuels and high-power power devices. Among the highly regarded zero carbon energy sources, ammonia powered ships have an energy density 50% higher than liquid hydrogen, and can utilize existing ammonia supply chains and infrastructure. They have good prospects for promotion and application in the field of long-distance navigation of large ships such as container ships.
In addition, ammonia fuel also has certain application scenarios in road transportation. Amino fuel cell vehicles, trucks, and buses not only have high efficiency and no emissions, but also have advantages such as strong endurance and fast replenishment time. By utilizing existing fuel cell technologies, ammonia fuel can achieve a power density similar to hydrogen fuel at the same temperature, and is considered an ideal fuel that can replace pure hydrogen for fuel cells.
Current issues and challenges of ammonia fuel
2.1 Safety issue
Ammonia is toxic and corrosive, posing a safety hazard. According to the Classification of Occupational Exposure to Toxic Substances, ammonia gas belongs to Class IV mild hazard gas. When exposed to an environment containing a certain concentration of ammonia gas, wet skin, mucous membranes, and eyes may be invaded by ammonia gas, which may lead to poisoning accidents, causing severe cough, bronchospasm, acute pulmonary edema, and even blindness and suffocation death. Ammonia also poses an explosion hazard. When the concentration of ammonia in the air mixture reaches 16%~25%, it can cause an explosion when exposed to an open flame. It belongs to the Class B fire hazard gas specified in the Fire Protection Design Code for Petrochemical Enterprises. In addition, liquid ammonia is highly prone to gasification, and there is also a risk of physical explosion in ammonia storage tanks. In the process of ammonia production and storage, if there is a leak, safety accidents may occur.
2.2 Environmental issue
Compared with other fuels, ammonia has a slower combustion rate and is still difficult to apply in "fast response" scenarios. At present, the relevant technology of ammonia combustion is not yet mature. When ammonia combustion is not sufficient, the reaction process will produce a large amount of nitrogen oxides (NOx), which may cause air pollution such as acid rain, ozone holes, photochemical smoke, and other environmental problems.
2.3 Economical issue
At present, more than 80% of synthetic ammonia in China is produced by coal gasification to produce hydrogen gas, which is then processed and synthesized. The main raw material for synthetic ammonia is still "gray hydrogen", and its production is a high carbon process, which will emit a large amount of carbon dioxide.
With the development of renewable energy hydrogen production technology, "green hydrogen" has provided the possibility for the synthesis of "green ammonia". However, the current cost of renewable energy generation, electrolytic water hydrogen production systems, etc. is relatively high, and "green hydrogen" and synthesized "green ammonia" are still relatively expensive. According to pilot project data, the cost of "green ammonia" is more than 50% higher than coal to synthetic ammonia, and "green ammonia" is not economically feasible in the short term.
The Enlightenment of "Global Ammonia Economy" for China
With the acceleration of global green and low-carbon development, many countries have shown great interest in promoting the application of ammonia and actively layout ammonia? The hydrogen industry, with a focus on ammonia gas turbines, ammonia fuel powered ships, and ammonia? Research on hydrogen transportation and other aspects also provides new ideas and directions for China to achieve carbon peak and carbon neutrality.
3.1 Current situation of ammonia industry
(I) Power generated by ammonia fuel
Under the vision of carbon neutrality, promoting the co combustion or pure combustion of low-carbon fuels such as liquid ammonia in thermal power units is an important technical direction for reducing pollution and carbon emissions in the power generation field. At present, some countries represented by Japan are exploring the development of ammonia based thermal power generation technology to accelerate the decarbonization process of the power sector. Among them, Japanese laboratories and engineering companies have tested and developed small-scale ammonia gas turbines of 50-2000kW; Mitsubishi Heavy Industries is developing a 40MW ammonia gas turbine, which will use 100% ammonia for power generation and combine selective catalytic reduction with new combustion technologies to reduce nitrogen oxides produced by incomplete ammonia combustion. This technology can be used for industrial applications or power plants on remote islands, and Japan plans to achieve commercial application by 2025. In June 2021, GE Power Company in the United States also announced the signing of a memorandum of understanding with Japan's Ishikawa Island Corporation (IHI) to jointly develop an ammonia gas turbine roadmap.
(II) Ships powered by ammonia fuel
In October 2020, the ammonia fuel powered ultra large liquefied gas transport ship developed by China Jiangnan Shipbuilding Group was awarded a principal recognition certificate by Lloyd's Register of Shipping in the UK. In March 2021, the 40000 m3 medium-sized liquefied gas carrier powered by ammonia fuel developed by Jiangnan Shipbuilding Group once again received the principal recognition certificate issued by Lloyd's Register of Shipping in the UK, effectively proving the feasibility of ammonia as a shipping fuel and an important milestone in the shipping industry's use of alternative fuels to promote zero carbon emissions.
South Korean shipbuilding companies are also committed to developing ammonia fuel propulsion ships and seizing the high ground of green power energy technology. In July 2020, the ammonia powered intermediate range refined oil tanker designed by Hyundai Weipu Shipbuilding received a principal recognition certificate from Lloyd's Register of Shipping in the UK, with a carrying capacity of 50000 tons. It is expected to achieve commercial operation by 2025. In January 2021, the Korean Classification Society released a research report on ammonia fuel powered ships, elaborating on the production and use of ammonia, economic benefits, safety characteristics of treatment facilities, ammonia fuel cells, and internal combustion engines.
European countries such as Norway and Finland have very strict environmental requirements, and many ports plan to implement zero emissions. They also plan to start using ships powered by ammonia fuel in the coming years. Wartsila, a Finnish marine engine manufacturer, Eidesvik, a Norwegian marine engineering ship owner, and Equinor, a Norwegian oil company, are cooperating to develop a zero-emission large ship powered by ammonia fuel cells that can complete long-distance navigation. It is expected that the ship will be launched as early as 2024, when it will become the first commercial ammonia powered ship sailing on the high seas.
(III) Ammonia-hydrogen transportation
Ammonia can not only serve as a fuel to provide power, but may also become an important carrier for large-scale hydrogen transportation in the future. On the one hand, compared with hydrogen, ammonia is highly prone to liquefaction, and the difficulty of transporting liquid ammonia is greatly reduced; On the other hand, the volumetric hydrogen storage density in liquid ammonia hydrogen storage is 1.7 times that of liquid hydrogen, and it is also much higher than the current mainstream high-pressure long tube trailer storage and transportation of hydrogen.
Based on the ammonia hydrogen transportation mode, ammonia is considered a key carrier for promoting the export of renewable energy. It has obvious advantages in large-scale "green hydrogen" export projects and has become an important direction for countries such as Japan, Australia, and Singapore to actively layout. In 2018, the Australian Renewable Energy Agency announced an investment of $20 million to support renewable energy exports, including renewable energy export technology using ammonia as a carrier. The renewable energy roadmap released by the Japanese Ministry of Economy, Trade and Industry shows that after 2030, Japan may import $10-20 billion of hydrogen annually, which will also generate a large demand for ammonia hydrogen transportation market.
3.2 Enlightenment for China
With the gradual replacement of fossil fuels, ammonia may become an important component of global energy trade due to its convenient transportation. While countries around the world are actively researching and laying out the "ammonia economy," China should also actively research new technologies such as ammonia gas turbines, power ships, fuel cells, and ammonia hydrogen transportation, and strive to promote disruptive technological innovation in the integration of zero carbon energy and ammonia hydrogen. Based on the development of China's hydrogen energy industry, timely layout of the "green ammonia" industry, and promote the pilot demonstration and promotion application of ammonia fuel.
Of course, ammonia fuel is an option for zero carbon alternative energy, but it is not the only solution. Whether it is synthesizing ammonia from hydrogen and nitrogen or converting ammonia into hydrogen, there will be a certain amount of energy loss, and the large-scale application of ammonia fuel also faces great challenges. To achieve the goal of carbon neutrality, various fields need to conduct research and exploration from multiple perspectives and directions based on actual energy demand and technological development prospects, and ultimately choose an economically feasible zero carbon decarbonization technology route.
Conclusion
Synthetic ammonia is one of the important products in traditional chemical industry, with the characteristics of wide application, mature technology, and complete industry. Under the background of carbon peak and carbon neutrality, ammonia fuel can become an important alternative to fossil fuels due to its advantages of zero carbon emissions, convenient storage and transportation, and high thermal efficiency. It has broad application prospects in power generation, transportation, and hydrogen storage. Although ammonia still faces many challenges in terms of safety, environmental protection, and economy as an alternative energy source, "green ammonia" provides a new path to achieve zero carbon decarbonization. Against the backdrop of the high enthusiasm of countries around the world to layout the "ammonia economy", China should also seize the historical opportunity of low-carbon energy transformation and development, actively carry out key technology research and innovation such as ammonia blending/pure ammonia combustion and power ships, Guide suitable regions to layout "ammonia hydrogen" demonstration projects in combination with advantageous industries, coordinate the integrated development of synthetic ammonia industry, renewable energy, and hydrogen energy industry, and promote the substitution of low-carbon ammonia fuel for fossil energy in areas such as electricity and navigation that are difficult to reduce emissions.
