Wang Xiji Academician Collection

Author: Wang Xiji / Country: Mainland China
Publisher:
Publish Date: 2006-03-01
Features: The total power consumption of energy in the world is currently about 1 billion kW. With the increase in population, development of modernization, and improvement in living standards, the demand for energy is estimated to increase by approximately 4% annually. By 2000, the total power consumption may approach 1.9 billion kW, requiring about 20 billion tons of standard coal annually. If all energy relies on traditional resources, it is estimated that they can only sustain humanity for two to three centuries. This poses a significant problem. Therefore, new energy sources and future energy resources have become a major concern for humanity. Research on this topic is being conducted worldwide. On Earth, solar energy, wind energy, hydrogen fuel, thermal fusion energy, and biomass energy all have the potential to become important new energy sources. Space is abundant in energy. The solar energy received by the Earth's surface is extremely large, with a power of approximately 9×10 kW, which is 9,000 times the current total power consumption of the world. However, converting this abundant solar energy into usable energy by establishing large-scale solar power conversion facilities on Earth is extremely difficult due to the following reasons:
1) Only about half of the year can receive sunlight, and the intensity of sunlight varies over time, meaning the efficiency is low and it is difficult to serve as a basic load power plant.
2) Due to wind and gravity, constructing large-scale solar cell arrays or mirror groups is limited.
3) Due to atmospheric and ground pollution, either automatic cleaning equipment must be designed or regular cleaning must be performed.
This is why, despite the large amount of solar energy received by the Earth, solar energy is unlikely to become a major energy source in the present or even in the next few decades.
A 100-km-wide ring belt (equivalent to ±6°) in the geostationary orbit of the Earth is estimated to receive solar energy with a total power equivalent to that of the entire Earth. This demonstrates that the energy resources in space are extremely abundant. Establishing large-scale power stations in space to develop space energy has many advantages. Of course, there are also many technical difficulties to overcome. However, after two decades of research and experiments in space science and technology, it can be considered scientifically feasible to establish large-scale space power satellites in the geostationary orbit, convert solar energy into electricity, and transmit the electricity to the ground via microwaves or lasers. At the current level of technology, there are no new scientific breakthroughs required.
Large-scale solar power stations established in space orbits can receive sunlight for 99% of the time, with only a few eclipse periods and a few hours near midnight in March and September when sunlight is not received. In space orbits, there is no atmospheric reflection or absorption of sunlight, no day-night changes, no variation in the solar angle, no seasonal changes, and no pollution from dust or harmful gases. Therefore, for the same area, the solar energy received in space is approximately 5 to 10 times that on Earth. Additionally, due to the weightlessness and windless environment in space, it is possible to use lightweight or deployable large components to construct large-scale solar cell arrays or solar mirror groups.
Developing and utilizing the abundant energy in space, establishing large power stations in space orbits—this is no longer just a discussion but a proactive effort. Research over the past decade by the United Nations, the European Parliament, the U.S. Department of Energy and NASA, ESA, the Soviet Academy of Sciences, and other organizations interested in developing space energy has shown that there are no insurmountable scientific challenges in establishing large-scale space power satellites. In other words, it is scientifically feasible to study, analyze, and demonstrate the possibility of establishing large power satellites in the geostationary orbit (e.g., a space power satellite with a ground power output of 5×10 kW).
We have now moved from the scientific feasibility stage to the engineering and technical feasibility stage of testing, analysis, and demonstration. This stage has progressed smoothly due to achievements in space shuttles and space stations. It is estimated that the development of ground support systems (such as vigorously promoting the development of ground solar energy utilization to achieve mass production of solar cells and reduce the cost of photovoltaic components) and launching experimental devices with power outputs of hundreds to thousands of kilowatts will accelerate in the 1980s. Between 2000 and 2030, large space power satellites may become a reality. It is estimated that the cost of generating one kilowatt-hour of electricity in space could be comparable to that of ground-based power plants.
If large-scale power stations in space are built to extensively harness solar energy for human use, humanity will have a better solution to the energy problem. Since the 1960s, global investment in space science and technology has averaged more than 10 billion U.S. dollars annually. Some may ask, what is the purpose of this? From the perspective of space resources, it can be explained. Space resources are precious and mostly difficult or impossible to obtain on Earth. Space resources are abundant, and developing them can yield significant benefits. Seeking and utilizing space resources is part of humanity's entry into space, exploration of space, and study of space, and it is also the main driving force behind investment in space science and technology. Generally speaking, space is open to everyone, and space resources belong to all of humanity; everyone has the right to develop and utilize them. In reality, only countries and groups with advanced scientific and technological levels and wealth, as well as those capable of purchasing satellites, can talk about developing and utilizing space resources and benefiting from them.
China has successfully launched 13 artificial satellites, five of which are recoverable scientific and experimental satellites. This indicates that China has a solid foundation in space science and technology for developing space resources. Of course, we should fully leverage our advantages and strive to develop and utilize space resources to benefit our country and people, especially those benefits that cannot be obtained through other means.
P29-30