Most of the energy belongs to the broad sense of solar energy, if there is no sun, how can humans get enough energy? This September, the World Geothermal Congress will be held in China for the first time. As a rare source of energy from the earth's interior, geothermal energy is green and low-carbon, and the total amount is staggering, about 170 million times the global coal reserves, is a huge treasure. China is rich in geothermal resources and has broad market prospects. In order to successfully achieve green and low-carbon energy transformation, it is necessary to further improve the utilization level of geothermal energy.
Geothermal energy development and utilization can be divided into two aspects: direct utilization and geothermal power generation. Geothermal direct utilization includes heating, cooling, drying, hot spring bathing, etc. Ground source heat pump is the most important way of global geothermal direct utilization. The utilization of geothermal resources in China is mainly direct utilization, and the direct utilization of geothermal resources in China will exceed 40 GW in 2020, accounting for 38% of the global total. Although China's geothermal utilization has ranked first in the world for many consecutive years, it is not a geothermal power country, because in the field of geothermal power with greater potential, the installed capacity does not even rank in the top ten in the world.
The problem with the early direct application of geothermal energy is that it is geographically localized, because heat energy is difficult to carry out long-distance transmission, so it can only be used near the origin. If you want to make better use of geothermal energy, you need to turn it into electricity, and electricity can be transmitted over long distances with lower losses, which is why some geothermal countries pay more attention to power generation applications. Due to the low utilization level of geothermal energy, geothermal energy in China can only be digested locally and cannot be transferred in a large range.
Geothermal power is not complicated. In traditional thermal power plants, fossil energy such as coal, natural gas and oil is used as fuel to produce high-pressure steam for power generation. The difference between geothermal power generation is that the earth acts as a boiler by using geothermal water to form superheated steam and turn turbines to generate electricity. In addition to the energy source, geothermal power plants use essentially the same technology as coal, natural gas and nuclear power plants.
Geothermal power generation is a stable and reliable renewable energy source, with annual power generation hours of more than 8,000 hours, comparable to nuclear power, far higher than wind power and photovoltaic. At the same time, geothermal power generation also has the advantages of low carbon emissions during the average life cycle, stable load operation, adjustable frequency and pressure, less land resource occupation, and not affected by the weather, especially in Yunnan, Sichuan and other hydropower provinces when low water can be used. Geothermal power generation should have a place in China's diversified and complementary new energy system.
China's geothermal power generation started early and developed slowly. In the face of the world's first oil crisis, in 1970, former Minister of Geology Li Siguang advocated the development of geothermal energy, and successively built seven small distributed units represented by Dengwu in Fengshun, Guangdong. In 1977, China's first high-temperature geothermal generator set successfully generated electricity in Yangbajing, Xizang Province, and its power generation was as high as 60% of the Lhasa power grid. Due to insufficient policy support and other reasons, the subsequent development of geothermal power generation is slow, and there are only a handful of geothermal power plants in operation at present. By the end of 2020, China's installed capacity of geothermal power generation was 44.56 megawatts, far from reaching the target of 500 megawatts of new installed capacity proposed in the 13th Five-Year Plan.
In the first year of the "14th Five-Year Plan", the eight departments led by the National Energy Administration jointly issued the "Several Opinions on Promoting the Development and Utilization of geothermal energy", which made it clear that a number of geothermal power generation demonstration projects should be built in areas with good resource conditions, and the installed capacity of geothermal power generation in the country should double that of 2020. At present, domestic enterprises have mastered the key technologies of geothermal power generation and the core technologies of complete sets of equipment, and formed the large-scale development capability of geothermal power generation. However, if there is a lack of policy support, geothermal power generation may not be able to complete the national plan for the second time.
To promote the development and utilization of geothermal power generation, the primary task is to find out the family background. Unlike solar and wind power, geothermal energy is hidden underground and can't be seen or touched. Only by truly mastering the reserves and types of geothermal resources can we make better use of heat sources. It is necessary to encourage and guide social capital to invest in the general survey, detailed investigation, exploration and development of geothermal resources, with the focus on finding out the types, heat sources, hot channels, and characteristics and distribution of geothermal energy resources, evaluating the potential of geothermal energy, selecting favorable areas, and providing a resource base for geothermal energy power generation and large-scale development and utilization.
The introduction of electricity prices and related support policies is a necessary measure to promote the large-scale development of geothermal power generation. With reference to the rise of China's wind power and photovoltaic industries, the renewable energy price additional allocation policy has played a huge role in promoting its industrial development and technological upgrading. The development experience of leading geothermal power generation countries such as Indonesia, the Philippines and Turkey has also verified that technological progress and large-scale development cannot be achieved without subsidy policy support. Governments at all levels may consider the introduction of electricity prices and related support policies, organize the construction of medium-high temperature geothermal power generation projects in Tibet, western Sichuan, western Yunnan and other areas rich in high-temperature geothermal resources, and support the integrated development of geothermal power generation with other renewable energy sources.
Promoting technological breakthroughs in the utilization of deep geothermal energy is related to the long-term development of the industry. At present, the medium and shallow geothermal resources available in technology are not enough to support the installation of ultra-large scale geothermal power generation. It is necessary to encourage geothermal power generation enterprises to improve the development potential of geothermal fields, actively explore the commercialization of dry hot rock power generation, and continue to invest in the direction of establishing industry-university-research alliances in scientific research institutes and universities to build China's geothermal power generation program. (Author: Wang Yichen Source: Economic Daily)