Commercial PV Systems Generate Electricity Without Pollution
When light shines on the surface of the solar cell, some photons are absorbed by the silicon material, and the energy of the photons is transferred to the silicon atoms, causing the electrons to transition and become free electrons, which accumulate on both sides of the PN junction to form a potential difference. When the external circuit is connected, under the action of this voltage, there will be a current flowing through the external circuit to generate a certain output power. The essence of this process is the process of converting photon energy into electrical energy.
1. Commercial PV systems: least energy conversion link
From the perspective of energy conversion, commercial PV systems power generation directly converts solar radiation energy into electrical energy. Among all renewable energy sources, solar photovoltaic power generation has the least conversion process and the most direct utilization. Generally speaking, in the energy flow of the entire ecological environment, with the increase of the conversion link and the elongation of the conversion chain, the energy loss will increase geometrically, and at the same time greatly increase the construction and operation costs and instability of the entire system . At present, the practical level of photoelectric conversion efficiency of crystalline silicon solar cells is 15%-20%, and the highest level in the laboratory has reached 35%.
2. Commercial PV systems: the most economical and environmentally friendly
From the perspective of resource conditions, especially land occupation, biomass energy and wind energy are relatively harsh, while solar energy utilization is very flexible. If the land area occupied by solar photovoltaic power generation is 1, the wind power is 8-10 times that of solar energy, and the biomass energy is 100 times. As far as hydropower is concerned, the construction of a large dam often needs to submerge tens to hundreds of square kilometers of land. In contrast, solar power generation does not need to occupy more land. Roofs and walls can be used for solar photovoltaic power generation, and the vast desert can also be used to directly reduce the desert area by building solar photovoltaic power generation bases on the desert. The direct solar radiation to the surface can effectively reduce the surface temperature and reduce evaporation, which makes the survival and growth of plants possible to a considerable extent, stabilizes and reduces sand dunes, and obtains the clean and renewable energy needed from nature.
3. Commercial PV systems: free to use and no transportation required
Human beings can convert solar energy into thermal energy or electric energy through specialized technology and equipment, and use it on the spot without transportation, so as to benefit human beings. And it is also free for human beings to use the inexhaustible energy source of solar energy. Although the solar radiation is uneven due to differences in latitude and climatic conditions, compared with other energy sources, solar energy is universal in most areas on the earth and can be used locally. This provides a bright prospect for solving energy problems in countries and regions lacking in conventional energy sources.
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