Geothermal Energy Review

Geothermal energy is renewable heat energy from deep in the earth. It originated from the decay of the Earth's molten magma and radioactive material. The deep circulation of groundwater and the intrusion of magma from the deep into the earth's crust bring heat from deep underground to near surface. In some places, thermal energy reaches the ground with natural hot steam and water, and they have been used for bathing and cooking since prehistoric times. Through drilling, these heat energy can be introduced into the pool from underground reservoirs. Room, greenhouse and power station. This kind of thermal energy reserves are quite large. It is estimated that the annual thermal energy transmitted from the interior of the Earth to the ground is equivalent to 100 PW·h. However, the distribution of geothermal energy is relatively scattered and difficult to develop. In fact, if the Earth itself does not concentrate geothermal energy in certain areas (generally those areas related to the interface of the tectonic plate), geothermal energy cannot be used as a source of heat and electricity to generate electricity using the current state of the art. in use.

Strictly speaking, geothermal energy is not a "renewable" resource, but an energy like oil that can be mined, and the ultimate recoverable volume will depend on the technology used. Re-injection of water (heat transfer medium) back into the aquifer can improve the performance of the regeneration as it does not deplete the aquifer. However, there is no definite conclusion on this issue, because a considerable number of hot spots can be developed in a certain way, so that the extracted heat is equal to the naturally added calories. Practically speaking, in any case, even if geothermal energy is not technically a renewable energy source, the global potential for geothermal resources is very large. Therefore, the problem lies not in the size of the resources, but in whether there is a suitable technology for the economic development of these resources. come out.

Geothermal energy refers to the heat energy stored inside the earth. Its reserves are many times larger than the total amount currently used by people, and are concentrated in the area along the edge of the tectonic plate, which is also a volcanic and earthquake-prone area. If the rate of heat extraction does not exceed the rate of replenishment, geothermal energy is renewable. High-pressure superheated water or steam is most useful, but they are mainly found in dry hot rock formations and can be extracted by drilling.

Geothermal energy is widely used in many parts of the world. The old technology is still full of vitality. The new technology industry has matured and is constantly improving. In terms of energy development and technology transfer, there is considerable potential for future development. Geothermal energy is stored underground in nature and is not affected by weather conditions. It can be used as a basic load, but it can also be used as needed.

Use of geothermal energy People have used low-temperature geothermal resources for bathing and space heating since ancient times, and have recently been used for heating in greenhouses, heat pumps, and certain heat treatment processes. In commercial applications, there have been decades of power generation using dry superheated steam and high-temperature water. The use of medium-temperature (100°C) water to generate power through a two-fluid cycle power plant has made significant progress in the past 10 years and the technology is now mature. Geothermal heat pump technology has also made significant progress later. Due to the advancement of these technologies, the rapid development and utilization of these resources has also led to a significant increase in the potential of many countries' economically available resources. From a long-term perspective, the study of effective methods for extracting useful energy from dry rocks and from geothermal pressurized resources and magmatic resources can further increase the potential for geothermal energy applications. Geothermal energy exploration and extraction technologies rely on the experience of the petroleum industry, but in order to adapt to the special nature of geothermal resources (such as the high temperature environment of the resource and high salinity) requirements, these experiences and technologies must be improved. The exploration and extraction costs of geothermal resources account for a significant proportion of the total energy costs. These mature technologies have been successfully promoted to developing countries through the hard work of the relevant UN agencies (the United Nations Institute for Training Research and the United Nations Development Programme).