Broadly speaking, renewable energy includes all renewable and continuous energy sources in nature, such as large and medium-sized hydropower, small hydropower, solar energy, wind energy, biomass energy, geothermal energy, ocean energy, etc. In addition to conventional fossil energy and nuclear energy, many types of energy are renewable and belong to the category of renewable energy. Here, briefly discuss some of the most typical types of renewable energy.
1. Wind energy
Essentially, wind energy comes from solar energy, which is a form of conversion of solar energy under certain conditions. Simply put, the different latitudes of the earth’s surface are at different distances from the sun, the angle of receiving sunlight is different, and the time (including time and duration) of receiving sunlight is also different, which makes the temperature distribution on the earth’s surface uneven, leading to temperature differences in various places, which in turn causes differences in atmospheric pressure over different regions. Under the action of atmospheric pressure, the air moves. Moving air has energy, and wind energy is the kinetic energy of moving air. For human beings, wind energy is a natural resource with huge reserves, widespread distribution, and renewable. It also has the advantages of zero pollution, zero emissions, and no need for transportation. However, this kind of energy also has disadvantages such as difficulty in storage, low energy flow density, and instability. Therefore, for a long time, wind energy has not been able to be used by humans on a large scale. With the continuous advancement of science and technology, the use of wind energy has gradually become more widespread.
Solar energy is the energy carried by solar radiation, and it is the most important renewable energy source for mankind. Studies have shown that about 1.73×1011MW of energy is output from the yang to the universe every year. The part of this energy that can reach the earth accounts for about one part of 2.2 billion, or about 8.5×1010MW, which is equivalent to the energy released by the burning of 1.7×1018t Huai coal. This is a huge source of energy for the earth, far exceeding the total amount of energy consumed by human beings each year, and neither the value of development nor the space for development is huge.
3. Biomass Energy
Biomass energy is a kind of renewable energy that has not been used on a large scale by human beings, and it is also a kind of renewable and recyclable energy. Biomass energy mainly includes various plants that can be used for energy in nature, human and livestock excrement, and energy converted from organic waste in urban and rural areas. From the analysis of its source, biomass energy is the energy stored in biomass by green plants that convert sun energy into chemical energy through chlorophyll. According to conservative estimates, the plants on the ball can fix 200 billion tons of carbon each year through photosynthesis, and the energy contained therein is about 3×1021J, which is twice the current annual consumption of mineral energy in the world.
4. Geothermal energy
When it comes to geothermal energy, many people may find it strange. But hot springs are well known. In fact, hot springs are the “natural utilization” of geothermal energy. Geothermal energy is the sum of the thermal energy of molten magma in the earth and the thermal energy produced by the decay of radioactive materials. At present, there is still controversy in the scientific community about the origin of geothermal energy. However, the reserves of ground energy are very huge, and the utilization value is very considerable. Geothermal energy has the characteristics of distribution, cleanliness, high heat flow density and convenient use. The total amount of geothermal resources in the world is 1.45×1026, which is equivalent to 170 million times the global coal thermal energy. From the perspective of the form of resource storage, geothermal energy can be divided into four types, namely hydrothermal type, ground pressure type, dry rock type and magma type. Among them, the hydrothermal type can be divided into three major types, namely dry steam type, wet steam type and ice accumulation type. From the perspective of temperature, geothermal energy can be divided into three types, namely high temperature, medium temperature and low temperature. Among them, the temperature of the high temperature type is generally higher than 150℃, the temperature of the medium temperature type is between 90 and 149℃, and the temperature of the low temperature type is lower than 89℃.
5. Ocean Energy
Ocean energy is an energy source attached to the sea, including tidal energy, tidal current energy, ocean current energy, wave energy, sea temperature difference energy and sea salt difference energy. This kind of energy has the advantages of large reserves, pollution-free, renewable and other aspects. It is estimated that the theoretical renewable amount of ocean energy in the world is 7.6×1013w, which is equivalent to the current total demand for electric energy by mankind.
6. Hydrogen energy
Hydrogen energy is a secondary energy that is being actively developed in the world’s renewable energy industry. Two hydrogen atoms and one oxygen atom combine to form a water molecule. Hydrogen is easy to burn in oxygen to release heat, and then hydrogen molecules chemically react with oxygen molecules to produce water. Since the combination of hydrogen molecules and oxygen molecules does not produce CO2, SO2, smoke and other atmospheric pollutants, hydrogen energy is regarded as the most ideal clean energy in the future. The international raw materials for hydrogen energy production mainly come from minerals, fossil fuels, biomass and water; hydrogen production processes mainly include electrolysis hydrogen production, pyrolysis hydrogen production, photochemical hydrogen production, radioactive energy hydrolysis hydrogen production, plasma electrochemical hydrogen production and biological hydrogen production, etc. Hydrogen energy is not only clean and efficient, but also has various conversion forms, and can be made into fuel cells that use it as a fuel. In the 21st century, hydrogen energy will become an important secondary energy source, and hydrogen power generation will also become a brand-new power generation method with the most industrial competitiveness.
This article is about the classification of renewable energy. For the energy classification methods, please refer to the previous article.