Geothermal energy promises to turn defenders into strikers



"As the country pays more and more attention to deep geothermal energy, the future geothermal energy is expected to change from the original 'guard' to 'center' or 'forward'." Pang Zhonghe, director of the Geothermal Resources Research Center of the Chinese Academy of Sciences, recently said in an interview with the China Science Journal.

Previously, researchers from Florida University of Technology and other universities in the United States published a paper in the European Journal of Physics, saying that the geothermal efficiency obtained through shallow Wells will gradually decrease over time, and may become ineffective within decades, if technology and funding allow, deeper drilling should be considered.

However, Pang Zhonghe pointed out that in terms of high-temperature geothermal power generation and deep geothermal energy development and utilization technology, developed countries such as Europe and the United States have studied for nearly 50 years, while China has just started, and there is still a gap with foreign countries.

"To catch up, you have to strengthen basic research on the one hand, and make basic research work for industry on the other." Pang Zhonghe said.

Earth "Charging/Hot Treasure"

In the face of the goal of "reaching the peak of carbon before 2030 and achieving carbon neutrality before 2060", geothermal energy as a clean non-carbon-based renewable energy has ushered in unprecedented development opportunities. Recently issued the "State Council on accelerating the establishment of a sound Green low-carbon circular Development of the economic system Guidance" clearly pointed out that to develop geothermal energy according to local conditions, speed up the development and promotion of large-capacity energy storage technology.

In order to further promote the development of geothermal geology and deep geothermal energy in China, the joint launch meeting of the Strategic research project "Geothermal Geology and Deep Geothermal Energy" of the National Natural Science Foundation of China was held at the Institute of Geology and Geophysics of the Chinese Academy of Sciences on March 19. The meeting was chaired by Wang Jiyang, academician of the Chinese Academy of Sciences. Many experts jointly "feel the pulse" of China's geothermal energy efficient use and sustainable development.

As the project leader of "Research on Earth Science Issues of Deep geothermal energy", Pang Zhonghe pointed out that underground "energy storage" is one of the important directions of the future development of geothermal energy, and through the recharge of various waste heat to underground space storage, geothermal energy can effectively play the role of continuous and stable base load. "It is like changing the original disposable battery to a rechargeable cycle battery to solve the problem of large-scale long-term storage of energy."

Li Kewen, a professor at China University of Geosciences in Beijing, put it bluntly: "It is difficult for China to achieve carbon neutrality within the specified time by relying only on current clean energy such as wind and solar energy. We must vigorously develop and use geothermal energy."

In fact, as early as 2018, Li Kewen's team proposed the concept of "zero carbon China", also studied the feasibility and technical route of realizing "zero carbon China", and started the relevant research on zero carbon buildings on the basis of technologies such as thermal volt power generation, and obtained the relevant national invention patent authorization.

According to the white paper "China's Energy Development in the New Era" released by The State Council Information Office, China's geothermal industry currently ranks first in the world in terms of total heat utilization, and by the end of 2019, the construction area of shallow and medium deep geothermal energy heating in China exceeded 1.1 billion square meters. "One square meter of geothermal heating area per capita is still too little, and there is still huge room for development in the future." Pang Zhonghe said.

Conduct prospective studies

In 2017, the "13th Five-Year Plan for Geothermal Energy Development and Utilization" jointly prepared by the National Development and Reform Commission, the Ministry of Land and Resources and the National Energy Administration was officially released, and China's geothermal industry ushered in the "second spring" and gradually embarked on the road of high-quality development.

"For the development and utilization of geothermal energy, it is not only necessary to break through the current technical bottleneck, but also to explore the technologies that may be 'stuck' in the future from now on." Li Kewen told reporters.

Pang Zhonghe said that the realization of geothermal curve overtaking can not carry out repeated simple research, we must find out the world's frontier problems, find out the current major demand and bottleneck problems of geothermal in China. In addition, we should make good use of the existing research capabilities and recognize the actual situation of our geothermal research team, platform and research accumulation.

To this end, he suggested that we should further strengthen the research on geothermal resources in the Tibetan Plateau and its surrounding areas, sort out the key geological problems of geothermal exploitation, solve the technical problems of deep geothermal energy development and utilization, reveal the impact of major Cenozoic tectonic-thermal events on deep geothermal energy, and carry out research on key issues of deep underground high-temperature energy storage systems.

"Seismic induced by deep geothermal mining is an international research hotspot, although China has accumulated in this area, it is still necessary to sort out key scientific issues such as the dynamic failure law and failure criteria of complex geothermal rock mass, the fracture activation and expansion law under multi-field coupling conditions, and the multi-field coupling disturbance process and main control factors to induce earthquakes." Combined with the national strategic needs, the research direction framework of induced earthquakes in deep geothermal in 2025 is formulated." Pang Zhonghe pointed out.

Professor Guo Qinghai of China University of Geosciences (Wuhan), who is in charge of the project "Development Strategy of Research and Development of high-temperature hydrothermal geothermal resources in Southwest China", said that hydrothermal geothermal resources are currently the main object of human development and utilization, and the construction of large-scale geothermal power stations in the world is preferred to high-temperature hydrothermal geothermal areas. The global total geothermal power generation reached 14,369MW, most of which came from the contribution of high-temperature hydrothermal systems.

In his view, high-temperature hydrothermal geothermal resources are more valuable and efficient in theoretical research, development and utilization than medium and low temperature hydrothermal geothermal resources. In addition, under the current economic and technological conditions, the development and utilization of high-temperature hydrothermal geothermal resources is more common and feasible than that of dry-hot rock geothermal resources.

Guo Qinghai pointed out that the distribution of hydrothermal geothermal resources in China is not uniform, especially the high-temperature hydrothermal geothermal resources are mainly distributed in the southwest of southern Tibet, western Yunnan, western Sichuan and southeast Taiwan.

"To find out the distribution law of high-temperature hydrothermal geothermal resources, the formation mechanism of high-temperature hydrothermal system is the key. In addition, it is necessary to identify the weak links in the completed investigation and research of high-temperature hydrothermal system in southwest China, and clarify the development bottleneck of its exploration, development and utilization technology." Guo Chung-hai stressed.

It is urgent to strengthen policy support

In recent years, China's investment in geothermal energy technology research and development has gradually increased, but the factors restricting the development of geothermal energy still exist, among which the high cost is an important reason for many investors to be discouraged.

A silver sheet, as long as the hand on it can generate current, the reporter experienced the latest research and development of Li Kewen team thermal volt power generation results. "As long as there is a temperature difference, you can convert heat energy into electricity." 'said Lee Kelvin.

Over the years, Li Kewen's team has been concerned about the docking of geothermal energy research and industry, he said frankly, "High-cost high-temperature drilling is still an important constraint on the development and utilization of geothermal energy, the government should increase subsidies and other support, while formulating relevant policies to pay attention to the extension of technology, too fine and too strict are not conducive to the development of new technologies."

"There is a shortage of geothermal research talents in China, and the systematic geothermal energy teaching system from undergraduate, master's and doctoral students should be improved as soon as possible." To this end, China University of Geosciences (Beijing), approved by the Ministry of Education, has set up a new geothermal related undergraduate major. Of course, it is also necessary to avoid blindly following the trend of geothermal discipline. In addition, the government and society should create the right atmosphere of public opinion, raise the wages of young people, and encourage more young people to enter the geothermal and other manufacturing industries. Li Kewen said.

For the "14th Five-Year Plan" period how to better promote the efficient development and utilization of geothermal energy, Wang Jiyang and Pang Zhonghe put forward five suggestions from the system and policy aspects, one is to adjust the "policy heating line" boundary from the Yellow River to the Yangtze River; The second is to promote the "franchise" and other effective market access mode, based on opening up to improve the quality of industrial development; The third is to provide electricity price subsidies for geothermal power generation to change the backward situation of geothermal power generation in China; Fourth, based on the nature of geothermal energy renewable energy, the implementation of tax exemption policy; The fifth is to reform the management mechanism of geothermal mineral rights and form a new mechanism suitable for geothermal fluid minerals.

In addition, they also pointed out that the "14th Five-Year Plan" should face the future to support new research directions and strengthen the strategic scientific and technological strength of geothermal energy. It will focus on supporting the research and development of "front-end" technologies such as underground "energy storage" and developing an integrated energy system with complementary advantages. "Forward" and "defender" echo, forming a multiplier effect and all-weather support ability.