It must be inexhaustible, and environmentally friendly, does such an ideal energy source exist? At the 2024 Pujiang Innovation Forum "Future Energy Forum", experts and scholars introduced the development prospects of a variety of new energy sources and the iterative possibilities of energy storage methods. Through these latest developments, mankind has partial answers to the question of the future of energy.
Green fuels: "CO2 electrocatalysis" could disrupt the industry
In order to achieve the dual carbon goal, we have to pay attention to one key industry - shipping. Huang Zhen, academician of the Chinese Academy of Engineering and dean of the Institute of Carbon Neutrality at Shanghai Jiao Tong University, provided a set of data: 80% of the world's total freight volume is borne by ships, and the vast majority of these ships use reciprocating engines. In 2022, the global shipping industry emitted more than 1 billion tonnes of carbon dioxide, which is equivalent to the world's sixth-largest emitter if you compare it to national emissions. Therefore, carbon reduction in the shipping industry deserves great attention.
In the future, inland waterway shipping and offshore point-to-point shipping will be electrified as much as possible, but it is difficult for ocean-going shipping to be powered by batteries, forcing the industry to switch to "green fuel ships". The so-called green fuel refers to the fuel with high energy density converted from renewable energy, mainly including hydrogen, alcohol, ammonia, green gasoline and diesel, sustainable aviation fuel, etc.
Among them, hydrogen fuel is the most well-known, and there are several relatively mature preparation methods. The challenge, however, is that hydrogen is energy-intensive to store and transport, and as a hazardous chemical, it has a very wide explosion limit. The preparation process conditions of green ammonia are harsh, requiring high temperature and high pressure, and high energy consumption. Green methanol has gradually become popular in recent years, and many provinces and cities in mainland China have explored it from three different routes.
Huang Zhen revealed that the team of Shanghai Jiaotong University is developing a disruptive technology that has always been very challenging, that is, the use of carbon dioxide electrocatalysis to synthesize fuels. Their goal is to build a distributed renewable synthetic fuel preparation system by 2026, complete the large-scale manufacturing of high-consistency and long-life electrolyzer reactors in 2028, and complete the mass engineering operation of renewable synthetic fuel systems in 2030.
Wei Wei, vice president of the Shanghai Advanced Research Institute of the Chinese Academy of Sciences, pointed out that green fuels are becoming a key entry point for getting rid of fossil energy dependence at home and abroad. As an important connection point between the mainland and the world, Shanghai has undertaken the mission of building the "five centers", and the development of green fuels is of great significance.
Wei Wei said that in terms of developing green fuels, the local availability of biomass is relatively limited, which is not conducive to large-scale production. However, in terms of green power required for hydrogen production, if offshore wind power can be combined with marine energy, offshore photovoltaic and marine biomass to create an integrated offshore energy island in the future, it will provide strong support for Shanghai's green power and green hydrogen supply. In addition, in the disruptive technology routes of green methanol, sustainable aviation fuel, green ammonia, green gasoline and diesel, there are scientific research teams in Shanghai that are conducting relevant research, and some of them have made breakthrough results, which are at the leading level in China and even in the world.
Controlled nuclear fusion: three major technical challenges, commercial work has a long way to go
Fusion energy has always been a popular option on the road to exploring the energy of the future, but it always seems to be out of reach. Liu Yong, chief scientist of China National Nuclear Corporation and director of the Science and Technology Committee of the Southwest Institute of Physics of the Nuclear Industry, said that the advantages of nuclear fusion energy lie in abundant resources, inherent safety and environmental friendliness. Compared with traditional fossil fuels, a 1 million kilowatt power plant needs 2.5 million tons of coal and 1.3 million tons of oil a year, while only 100 kilograms of deuterium and 150 kilograms of tritium are needed.
In terms of preparation methods, magnetic confinement tokamaks are currently recognized as the most mature and pioneering technology to realize the application of controlled nuclear fusion energy, and the most representative project is the International Thermonuclear Experimental Reactor (ITER) program, which Continental officially joined in 2007. In March last year, the Southwest Institute of Physics of the Nuclear Industry led the release of the world's first international standard in the field of nuclear fusion. In June this year, as a large-scale scientific device independently designed and developed by the mainland, "China Gyre-3" discovered and realized an advanced magnetic field structure for the first time in the world, which is of great significance for improving the control and operation ability of nuclear fusion devices.
However, Liu Yong admits that controlled nuclear fusion still has a long way to go before it can be commercialized. At present, there are still three major technical challenges in the field of magnetic confinement nuclear fusion: steady-state self-sustaining operation of combustion plasma, resistance to high-energy neutron bombardment and high heat load materials, and tritium breeding and self-sustaining cycle. At the engineering level, strong-field high-temperature superconducting magnets, plasma operation and control, and heat conduction are currently facing difficult problems.
Long-term energy storage: breakthroughs have been achieved in both air and gravity paths
In the context of achieving the dual carbon goals, new energy power generation such as wind power and solar power generation is developing rapidly, and its volatility brings challenges to the stable operation of the power system and the balance between supply and demand, and it is necessary to solve the problem of power balance over several days, weeks and even across seasons. Luo Bixiong, chief scientist of China Energy Construction Group Co., Ltd. and national engineering survey and design master, pointed out that the development of long-term energy storage is of great significance to the mainland to ensure energy security, promote green and low-carbon energy transformation, and promote high-quality energy development.
Different from lithium batteries, the energy storage capacity of long-term energy storage can be decoupled from the discharge power, that is, the larger the capacity of the energy storage part, the longer the discharge time, so the capacity of the energy storage part can be increased at a lower cost, thereby extending the discharge time.
Long-term energy storage is mainly achieved through compressed air energy storage and gravity energy storage. The former relies on large underground caverns or above-ground gas storage chambers for gas storage, and can be used as a powerful supplement to pumped storage with breakthroughs in cryogenic liquefaction and supercritical technologies. The latter adopts a modular design, strong scalability, and can carry out intensive utilization of resources, which is conducive to improving the scale and flexibility of energy storage.
In the field of compressed air energy storage, in April this year, the world's first (set) 300 MW compressed air energy storage power station - Hubei Yingcheng 300 MW compressed gas energy storage power station demonstration project was successfully connected to the grid for the first time. In the field of gravity energy storage, China Energy Construction China Power Engineering pioneered the 300 MW vertical gravity energy storage technology, built an ultra-heavy-duty transportation system, developed the first high-efficiency gravity generator set in China, and initially formed a modular engineering scheme with the largest single module capacity, high system efficiency and excellent economy.