Geothermal energy-the dark horse in clean energy (1)

As a new energy star, geothermal has become a dark horse in the energy field with the goal of peak carbon dioxide emission and carbon neutrality. So, what is geothermal, what are its advantages, and how to develop geothermal?

Geothermal energy, also known as geothermal resources and geothermal energy, is the heat stored in the earth and available for human use. At present, the available geothermal resources mainly include: natural exposed hot springs, shallow geothermal energy extracted by heat pump technology, geothermal fluid directly extracted by artificial drilling and heat in dry-hot rocks.

Resources mainly include shallow geothermal energy, hydrothermal geothermal resources and dry-hot rocks.

Shallow geothermal energy: refers to the renewable energy with the temperature below 25 degrees Celsius and hidden in shallow soil, rocks and water sources at a depth of 200 meters. Usually, technologies such as buried pipe, ground source heat pump or water source heat pump are used for heating or cooling. The development scale of shallow geothermal energy in China is higher than that in the world.

Hydrothermal geothermal resources: the most typical geothermal resources in the family, generally refers to geothermal resources with a temperature above 25 degrees Celsius, mainly in the form of liquid water and steam, mainly in the form of natural hot springs, gas springs and fluids buried 200 meters underground. Natural exposed hydrothermal resources can be directly developed and utilized, and underground geothermal fluids can be developed by manual drilling. Among them, according to the temperature, it can be further divided into three categories: high temperature (above 150 degrees Celsius), moderate temperature (from 90 degrees Celsius to 150 degrees Celsius) and low temperature (below 90 degrees Celsius).

Dry-hot rock: it is a new geothermal resource, and its temperature generally exceeds 180 degrees Celsius. It is a high-temperature rock mass buried thousands of meters underground, with no fluid or only a small amount of underground fluid (dense and impermeable). In 20 17, scientists from China drilled 236℃ high-temperature dry-hot rocks at the depth of 3705 meters in Qinghai * * and the basin.

Geothermal resources are expected to benefit from its unique and distinct advantages.

First, it is widely distributed and has a large amount of resources. The earth is a huge thermal reservoir, and the radioactive elements inside the earth are constantly undergoing thermonuclear reactions, and the temperature is very high. The temperature in the center of the earth is as high as 6000 degrees Celsius, and the high-temperature heat is released into space all the time through the thick stratum. Geothermal energy is about 654.38+0.7 billion times of global coal thermal energy, and more than 2 million times of global annual consumption of primary energy, which is inexhaustible. According to preliminary assessment, the exploitable amount of shallow geothermal energy in 336 cities above prefecture level is equivalent to 700 million tons of standard coal, which can meet the heating demand of about 30 billion cubic meters of buildings. It is estimated that the annual exploitable amount of hydrothermal geothermal resources in China is equivalent to 6543.8+884 million tons of standard coal, with a medium-high temperature power generation potential of 9.96 million kilowatts and an annual power generation capacity of 8 million kWh. The prospective resources of dry-hot rocks in China are equivalent to 8.56 trillion tons of standard coal, which is the most potential strategic alternative energy after the exhaustion of fossil energy such as coal and oil.

Second, low carbon, environmental protection, safety and high quality. Geothermal energy is an all-weather, renewable, green and clean resource. Its development and utilization is safe and stable, and it is much less affected by factors such as day and night alternation, seasonal exchange and climate change. Can work continuously for more than 8000 hours a year and maintain high efficiency.

Third, it has a wide range of uses and strong industrial driving ability. Humans have used natural hot springs for thousands of years, but the real large-scale utilization began in the early 20th century. 1904, Italy used geothermal energy to generate electricity for the first time in Ladrillo, which marked a revolutionary change in the utilization mode of geothermal resources. By 2020, 88 countries around the world have developed geothermal resources, and geothermal energy has been widely used in power generation, heating, refrigeration, bathing, greenhouse planting, aquaculture, industrial drying, agricultural drying, snowmelt cooling and other fields. The installed capacity of geothermal power generation in the United States ranks first in the world for many years, and Iceland uses geothermal energy to solve 90% of building heating in the country. China's geothermal utilization has basically formed the development and utilization pattern of geothermal power generation represented by Yangbajing in Tibet, geothermal heating represented by Tianjin and Xi 'an, convalescent tourism represented by the southeast coast, and planting and breeding represented by the North China Plain. By the end of 2020, China's geothermal heating area will reach 654.38+0.4 billion square meters. Because of its wide use, geothermal energy has high comprehensive utilization value. Through cascade utilization, multiple functions such as power generation, heating, bathing, recuperation and breeding can be realized at the same time, which can also promote the development of many industries such as industry, agriculture, tourism, medical care and service industry.

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