What's going on with geothermal heat?
Geothermal is a renewable energy source that refers to thermal energy stored within the earth. This energy comes from residual heat from the Earth's formation and from the decay of radioactive elements. Geothermal energy can be utilized by humans through geothermal power generation, ground source heat pumps, etc. It is a clean and sustainable form of energy. In recent years, as the world's attention to renewable energy has increased, geothermal energy has also become one of the hot topics.
1. The formation and source of geothermal energy
The formation of geothermal energy is mainly related to the accumulation of heat inside the earth. Sources of heat within the Earth include:
| heat source | Proportion | Description |
|---|---|---|
| original heat of formation | about 20% | The remaining heat energy from the formation of the Earth |
| radioactive decay | about 80% | The decay of uranium, thorium, potassium and other elements releases heat |
This heat is transferred to the surface near the earth's surface through crustal conduction, magma activity, etc., forming usable geothermal resources.
2. Classification of geothermal heat
According to the temperature and depth of geothermal resources, they can be divided into the following categories:
| Type | temperature range | Depth | Main purpose |
|---|---|---|---|
| High temperature geothermal | Above 150°C | 3-10 kilometers | generate electricity |
| Medium temperature geothermal | 90-150°C | 1-3 kilometers | Power generation and heating |
| Low temperature geothermal | 25-90°C | near the surface | Heating, hot spring |
3. How to utilize geothermal energy
Geothermal energy can be utilized by humans in a variety of ways, including:
1.geothermal power generation: Using high-temperature geothermal fluid to drive turbines to generate electricity is one of the most important ways to utilize geothermal energy.
2.Ground source heat pump: Utilizes the constant temperature characteristics near the earth's surface to provide heating or cooling for buildings.
3.Use directly: Including hot spring recuperation, agricultural greenhouse heating, industrial processing, etc.
4. Distribution of global geothermal resources
Geothermal resources are unevenly distributed around the world and are mainly concentrated at plate boundaries and areas with frequent volcanic activity:
| area | major countries | geothermal potential |
|---|---|---|
| Pacific Rim | United States, Japan, Philippines | high |
| Great Rift Valley | Kenya, Ethiopia | high |
| mediterranean region | Italy, Türkiye | Middle to high |
| iceland | iceland | extremely high |
5. Advantages and challenges of geothermal
Advantages:
1. Renewable and sustainable
2. Low carbon emissions
3. Not affected by weather
4. Can provide base load power
Challenge:
1. High initial investment cost
2. Restricted by geographical conditions
3. May cause small-scale earthquakes
4. Thermal reservoirs may be depleted
6. Geothermal development status and future
According to the International Energy Agency, global geothermal power installed capacity has grown steadily in recent years:
| Year | Global installed capacity (MW) | annual growth rate |
|---|---|---|
| 2015 | 12,635 | - |
| 2020 | 15,854 | 4.6% |
| 2023 | 17,200 | 2.8% |
In the future, with the development of enhanced geothermal system (EGS) technology, the utilization scope of geothermal energy is expected to be further expanded. This technology can develop deep geothermal resources by artificially creating cracks, allowing more areas to utilize geothermal energy.
7. Geothermal development in China
China is rich in geothermal resources, mainly distributed in Tibet, Yunnan, Taiwan and other regions. In recent years, China's geothermal utilization has developed rapidly:
| Project | data |
|---|---|
| Geothermal direct utilization | No. 1 in the world |
| Geothermal power generation installed capacity | About 50MW(2023) |
| Goals of the 14th Five-Year Plan | Added 100 million square meters of geothermal heating area |
China is actively promoting the development and utilization of geothermal energy, especially in clean heating in northern areas, where geothermal energy is playing an increasingly important role.
Conclusion
As a clean and reliable renewable energy, geothermal energy plays an important role in the global energy transformation. Although geothermal energy currently does not account for a high proportion of the global energy structure, its development potential is huge with technological advancement and increased investment. In the future, geothermal energy is expected to work with other renewable energy sources such as solar energy and wind energy to build a cleaner and more sustainable energy system.
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