Development Status and Prospect Analysis of China's Solid Oxide Fuel Cell Industry

Abstract: 

Solid Oxide Fuel Cell (SOFC) is a kind of energy conversion device that directly converts chemical energy of fuel into electric energy, which is not limited by the Carnot cycle, has high energy conversion efficiency, and has the advantages of wide fuel adaptability, cleanness and non-pollution, all-solid-state structure, and no use of precious metal catalysts, etc. SOFC technology has a wide range of applications, which is not only able to utilize the hydrogen energy with high efficiency and greenness, but also to realize the efficient and clean utilization of traditional fossil energy, and to contribute to the goal of carbon peak and carbon neutrality in China. SOFC technology has a wide range of applications, not only for the green and efficient use of hydrogen energy, but also for the efficient and clean use of traditional fossil energy, and will make an important contribution to the realization of China's goal of carbon peaking and carbon neutrality. The development status of SOFC industry at home and abroad is introduced, and the development prospect of the industry is analyzed; solutions and suggestions are put forward for the difficulties encountered in the development of SOFC industry in China.

China is currently the world's largest energy consumer, with fossil energy accounting for 85% of all energy consumption. China's energy is characterized by "rich in coal, lack of oil and little gas", and coal accounts for the largest proportion of its fossil energy consumption, which causes the problem of China's CO2 emissions, CO2 emissions in 2022 reached 12.1 billion t [1], accounting for 32.88% of the global total emissions, and the "dual-carbon" goal is under great pressure to achieve. The realization of the "dual-carbon" goal faces greater pressure. China's external dependence on oil and natural gas has reached 70% and 40%, respectively [2], posing a huge challenge to China's energy security. Under such a background, China's energy structure adjustment is imperative, and it is necessary to develop a diversified energy structure. Hydrogen energy plays a positive role in the process of "replacing coal and reducing carbon", especially for the green hydrogen produced by renewable energy sources such as wind and solar energy, which does not emit any CO2 emissions in its production and use. in recent years, the domestic hydrogen energy "hotness" is also rising, and in March 2022, the National Development and Reform Commission of China (NDRC) announced that it would launch a hydrogen energy research and development program in China. In March, 2022, the National Development and Reform Commission (NDRC) officially released the "Medium- and Long-Term Plan for the Development of the Hydrogen Energy Industry (2021-2035)", which clarifies the strategic position of hydrogen energy in China's green and low-carbon energy transformation.

Fuel cells can directly convert the chemical energy in the fuel into electrical energy, and according to the different electrolytes, there are mainly alkaline fuel cells (AFC), proton exchange membrane fuel cells (PEMFC), phosphoric acid fuel cells (PAFC), molten carbonate fuel cells (MCFC), and solid oxide fuel cells (SOFC), etc. SOFC is a kind of all-solid-state fuel cells, also known as ceramic fuel cells, and its main advantage is that it does not use precious metal catalysts, high operating temperature, wide range of fuel applications, high waste heat temperature, and suitable for cogeneration. SOFC is an all-solid-state fuel cell, also known as ceramic fuel cell, whose main advantages are that it does not use precious metal catalysts, high operating temperature, wide range of fuel applicability, high waste heat temperature, and suitable for co-generation of heat and power, and its development speed in recent years has been the first of all types of fuel cells [3-5].SOFC is able to not only make green and efficient use of hydrogen, but also realize the efficient and clean use of traditional fossil energy sources.

1. Current status of international industrial development

The United States, Europe, Japan and other developed countries in the SOFC technology is in a leading position, has basically realized the commercial operation of SOFC, the industrial scale is expanding.

1.1 The United States

In 1937, the United States manufactured the first SOFC in history; in 1962, the U.S. Westinghouse began researching SOFC, and obtained a breakthrough in the 1980s; in 2000, Siemens-Westinghouse manufactured a 200kW SOFC power station. The cumulative installed capacity of SOFC in the U.S. leads the world, and its main application scenarios are large and medium-sized industrial/commercial power supply. Bloom Energy is the strongest company in technology at present, with relatively mature technology and good operational reliability, and the main product specification of SOFC developed by the company is 50kW modules, and the combination of multiple modules can maximally achieve tens of megawatts of fuel cell system, and its products have been applied in Apple, Google and other companies. BloomEnergy cooperates with Samsung Heavy Industries, and expects to realize an annual installed capacity of 300MW for marine applications by 2022, and cooperates with South Korea SK Group in 2021 to increase the installed capacity of at least 500MW by 2022-2025. Another famous company in the global fuel cell field is Fuel Cell Energy (USA), which has developed a 250kW SOFC system capable of operating as an electrolyzer for hydrogen production or a fuel cell for power generation, and also capable of using a variety of fuels, including natural gas, renewable biogas, or hydrogen [6].

1.2 Europe

Unlike the U.S. SOFC market, which favors large and medium-sized industrial/commercial power supply systems, the main promotion direction of the European market is micro-CHP systems, of which the more representative companies are Sunfire, Ceres Power, Solid Power, Hexis, Elcogen, Convion, Topose, Bosch, etc. Germany's Sunfire is a global leader in the production of industrial electrolyzers based on alkaline and solid oxide technologies, with its SOC (solid oxide cell) stacks generating electricity in the forward direction and producing hydrogen through electrolysis in the reverse direction. In 2022, the company installed the world's first 2.6MW high-temperature electrolyzer at its Neste refinery in Rotterdam, the Netherlands. Sunfire is rapidly expanding its production capacity and has raised additional capital in recent years, securing $215 million in Series D financing in 2022 and signing agreements for up to 640MW of electrolyzers. Ceres Power (UK) is a leader in next-generation, low-cost fuel cell technology, with its unique Steel Cell technology, derived from Imperial College [7], which offers the advantages of fast start-up and high power density.Ceres Power products are commercially available in residential, commercial power generation and transportation applications. Because stainless steel has high thermal and electrical conductivity, it has a low operating temperature and fast startup for use in automobiles. Ceres Power has also been actively pushing the market for stationary power generation and SOEC in recent years.Ceres Power, which was acquired a 20% stake by Weichai Power in 2018, has already developed a 30kW range extender for commercial vehicles with Weichai Power, Bosch, and Cummins. Italy's Solid Power focuses on developing micro-CHP systems, and its 2.5kW scale ENGEN2500 system has a total efficiency of around 90%. More than 1,000 BlueGEN power systems have been sold as of 2018. Hexis is one of the world's leading companies in the field of high-temperature fuel cell technology. It designs and produces fuel cell-based micro-CHP units for single-family homes, multi-family apartment buildings, and small commercial applications, mainly for stationary applications with electrical power less than 10kW [8]. The current main commercial product has an electrical output of 1.505 kW with an electrical efficiency of 40% and a thermal output of 2.1 kW, with a total system efficiency of 90% and a system lifetime of 10 years. Estonia Elcogen's SOFC has set a world record of 74% in converting fuel to electricity. Elcogen's products are SOFC monolithic cells and stacks, and Elcogen plans to produce about 50MW of cells per year starting in 2021, while for SOFC systems it is partnering with Magnex, a Japanese developer of SOFC systems that is developing the SOFC system. Magnex is a Japanese SOFC system developer, and is developing a 250W SOFC portable system and a 1~5kW SOFC biogas/ethanol cogeneration system, with the goal of selling more than 3,000 SOFC products within three years [9]. Bosch in Germany is also actively laying out the SOFC industrial chain, investing twice in 2018 and 2019 in Ceres Power, a British electrostack manufacturer, introducing electrostack production lines, and developing a 10kW SOFC cogeneration system with a power generation efficiency of 60%, whose main application markets are small-scale industrial, commercial, and data centers [10].

1.3 Japan

Japan's SOFC industry is developing rapidly under the leadership of the New Energy and Industrial Technology Development Organization (NEDO), especially the government-subsidized household fuel cell cogeneration (ENE-FARM) program, which has mature and reliable small-scale household SOFC cogeneration technology, and the number of retained units ranks first in the world. Japan's main SOFC enterprises are Kyocera, Osaka Gas, Mitsubishi Hitachi, Aisin Seiki and so on. Kyocera began to develop fuel cells in 1985, and has been challenging the development of small SOFC technology, and Kyocera's battery stack was installed in Japan's domestic SOFC power generation system in 2011. Now it has realized the third generation of more miniaturized products, the product power generation power of 700W, achieving 90,000 hours of continuous operation, 360 times start-stop, 12 years of design life [11]. Mitsubishi Heavy Industries began to develop SOFC technology in the 1980s, developed a 10kW-class tube-type SOFC power generation system in 2001, and successfully operated a 200kW SOFC+MGT composite power generation system in 2013, and established Mitsubishi-Hitachi Power Systems in 2014 to focus on the research and development of SOFC combined-cycle large-scale power generation systems, and announced the commercialization of 250kW and 1 MW of power generation systems in 2018. In 2018, we announced the commercialization of 250kW and 1 MW combined power generation products.

2. Development status of SOFC industry in China

China's SOFC research and development work is mainly in scientific research institutes and universities, and the source of funding is mainly national or local scientific and technological project support. Shanghai Institute of Silicate Technology, Chinese Academy of Sciences, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, University of Science and Technology of China, China University of Mining and Technology, Huazhong University of Science and Technology and other units are in the long term adhere to the research and development of SOFC, after several decades of accumulation, has initially grasped the raw materials from raw material production, large-area mass production of a single-cell production and preparation, stack assembly to the design and development of the entire SOFC system technology. SOFC system design and development technology. However, compared with the advanced level and commercial application in Europe, America and Japan, China's SOFC industry is in the industrial demonstration to the commercial application of the transition stage, the dawn of commercialization began to appear, which attracted many enterprises began to participate in, and promote the development of the industry.

Chaozhou Three-circle Group is one of the main suppliers of SOFC diaphragm plates in the world, and has been supplying electrolyte sheets to Bloom Energy, a global leader in solid state fuel cells, since 2005. The company acquired CFCL in Australia in 2012, mastered the complete set of SOFC technology, and successfully operated a 100kW demonstration system consisting of three 35kW modules in 2022. 210kW High-temperature Fuel Cell Power Generation System Research, Development and Application Demonstration Project was successfully passed by Guangdong Huizhou Natural Gas Power Generation Company Limited in January 2023, which was carried out in cooperation with Guangdong Provincial Energy Group Co. In January, 2023, the "210kW High-temperature Fuel Cell Power Generation System R&D and Application Demonstration Project" was carried out in cooperation with Guangdong Energy Group Co. The six 35kW SOFC systems installed before and after this project have a total power of ≥210kW, an average net AC power generation efficiency of 61.8%, the longest running time of the machine has been more than 5,000 hours, and the system cogeneration efficiency is as high as 91.2%, which realizes the research and application demonstration of the 210kW SOFC stationary power generation system in clusters [12]. In May 2018, Weichai Power strategically invested in the world's leading SOFC technology company, UK Hilithium, and became its largest shareholder. At present, Weichai Power has realized the engineering breakthrough of SOFC technology and fully controlled the key core technology of new-generation SOFC, and its 120kW product released in February 2023 is the world's first high-power metal-supported SOFC, with a net power generation efficiency of more than 60%, and a CHP cogeneration efficiency of 92.55%, which is the world's highest in a large-scale SOFC system [13]. In addition to the above two listed enterprises, central enterprises like National Energy Group, PetroChina, Sinopec, Guangdong Energy Group, and Southern Power Grid are also actively laying out the SOFC industry, mainly because these enterprises have their own fuels, markets, and bias towards practical applications. In addition, there are several startups with strong technical strength, Ningbo SOFC is a more comprehensive technology in the SOFC industry, through the powder to the system of the technical route to the main flat SOFC, from the Chinese Academy of Sciences, Ningbo Institute of Materials, and now the largest system power to achieve 25kW. Ltd. is also from the Ningbo Institute of Materials, Chinese Academy of Sciences fuel cell team, the core technology is high-performance, long-life, high-reliability large-area flat-tube SOFC, has developed a 5kW level of power stacks, is developing SOFC systems. Xuzhou Huaqing Jingkun's technical background is Tsinghua University, and it will set up a 25MW battery production line in Xuzhou in 2019. Huake Fusai, whose technical background is with Huazhong University of Science and Technology, has also bridged the powder-to-system technology route and released a 5kW natural gas SOFC power generation system in 2015. Zhejiang Zhentai New Energy Company adopts a unique flat-tube battery structure, and the largest power reactor can be 1kW, with a reaction temperature of about 650℃, good operational stability of the power reactor, and also has the ability to make supporting systems.

3.Application Prospect Analysis

3.1 Application Scenario

Under the background of energy structure transformation and "dual-carbon" target, SOFC technology, because of its high efficiency, wide fuel adaptability, clean and non-polluting, all-solid structure, no precious metal catalysts and other technical characteristics, shows an increasingly broad application prospects, not only to achieve efficient and clean use of fossil energy, reduce carbon emissions, but also to promote the development of green hydrogen industry in China. It can not only realize the efficient and clean utilization of fossil energy and reduce carbon emission, but also promote the development of green hydrogen industry and improve the energy structure of China. Specific application scenarios are as follows:

(1) Small-scale household cogeneration system

Small SOFC cogeneration system can provide electricity and hot water for family houses, which has obvious advantages in energy saving and emission reduction as well as peak shaving and valley filling. There is a successful precedent in this regard in Japan, where more than 110,000 units of the household cogeneration product "ENE Farm" have been sold since May 2009 in total.

(2) Distributed power generation

With high efficiency, no noise, no pollution emission and flexible adjustment of power range, SOFC can provide fuel cell systems with power ranging from 100kW to tens of MW, which is especially suitable for distributed power generation or backup power for data centers, and the products developed by Bloom Energy have already been applied in many companies such as Apple, Google, Ebay, etc., and more than 130MW SOFC fuel cells have been installed in the United States. SOFC fuel cells have been installed in more than 130MW in the United States.

(3) Transportation

SOFC has also been popularized and applied as auxiliary or power source for vehicles, ships, drones, etc. In 2016, Nissan released the world's first SOFC-powered car, which is fueled by bio-ethanol and has a range of more than 600km. Bloom Energy, in cooperation with Samsung Heavy Industries, plans to apply its products to power ships, and it is expected that more than 100 ships will have SOFC fuel cells in their fleet by 2027. It is expected that by 2027, there will be more than 100 cruise ships requiring more than 4GW battery orders.

(4) Large Power Stations

Large-scale coal gasification fuel cell (IGFC) power generation technology with near-zero CO2 emissions is a power generation system that combines integrated gasification combined cycle power generation (IGCC) with high-temperature solid oxide fuel cells or MCFCs, which is a fundamental change in coal power generation technology because of higher power generation efficiency and lower CO2 capture costs [14, 15]. Mitsubishi-Hitachi Electric Power is committed to the research and development of SOFC combined-cycle large-scale power generation systems, and will commercialize combined power generation products of 250kW and 1MW specifications in 2018.

(5) Reverse electrolysis for hydrogen production

SOFC can generate electricity in forward operation and realize electrolysis in reverse operation, i.e., solid oxide electrolysis cell (SOEC), which can produce hydrogen through electrolysis of water, and store the wasted electricity that does not match with the load into hydrogen, and its electrolysis efficiency is as high as 85% to 95%, which is much higher than that of other electrolysis technologies.

3.2 Bottlenecks in the development of China's SOFC industry

3.2.1 Life span of power reactor

Energizer is the core component of SOFC, which mainly involves the development of high-stability sealing materials, high-efficiency and stable connector materials, low thermal stress, thermal gradient, low-cost core technology of the energizer, and only a few companies in the world have mastered the design and production technology of long-life and high-reliability energizer. The most difficult problem is the sealing material of the power reactor, the sealing of the power reactor is sealed with high temperature glass glue or high temperature ceramic glue, and the thermal expansion coefficients of the glass, metal and battery cells are different, in the high temperature, electric current, air current perturbation of the working conditions, the sealing structure of the power reactor is easy to be damaged and lead to the performance degradation, and the number of power reactor start-stop is seriously restricted. At present, China has not solved the sealing problem of flat-plate SOFC stack, and the service life of SOFC system cannot be guaranteed.

3.2.2 Development of high-power systems

100kW scale SOFC system is the most widely used system. In recent years, China has only begun to appear 100 to 200kW scale SOFC system demonstration device reports, in the reactor module design, integration and batch assembly, temperature field, flow field uniformity control, long cycle operation is still a lack of experience, do not have complete mastery of the relevant core technology. Only by developing a high-power system with high efficiency and long-cycle stable operation can the industrialization of solid oxide fuel cells be realized.

3.2.3 Inadequate supporting systems

The industry chain of SOFC is very long, and there are many corresponding supporting industries, such as the coating technology of bipolar plates, highly stable sealing materials, auxiliary system BOP related equipment, and lack of mature supporting supply system. In particular, the design, processing and testing of BOP equipment for SOFC auxiliary system are not perfect, and key equipment such as high-temperature heat exchanger, hydrogen circulating pump, steam generator, etc. need to be customized, and some of them even have to be imported, which makes the production and manufacturing cost of SOFC system high.

3.2.4 Lack of strong policy support

Europe, the United States, Japan and other advanced solid oxide fuel cell technology with the commercialization process can be seen, the development of the solid oxide fuel cell industry needs the government's leading planning and policy support, especially in the pre-commercialization stage, financial subsidies appear to be particularly critical. At present, China has targeted policy support in the field of PEMFC, but there is a lack of strong support policies in the field of SOFC, and the subsidies are not large enough compared with those of developed countries in Europe and the United States.

3.2.5 Insufficient capital investment

The well developed enterprises in the foreign SOFC industry have received strong support from capital, while in China, except for Chaozhou Three-circle Group and Weichai Power, which have relatively strong capital, most of the powerful enterprises belong to the start-up companies set up by research institutes based on years of research results, which makes financing more difficult and the progress of commercialized products slower. Insufficient capital investment, small market size, low profits, in turn, resulting in fewer relevant supporting enterprises, enthusiasm is not high, the development of SOFC industrialization caused by a double blow.