The advantages of solar PV power generation

The advantages and disadvantages of solar photovoltaic power generation

(1) Advantages

Solar photovoltaic power generation process is simple, no mechanical rotating parts, no fuel consumption, no emissions including greenhouse gases, no noise, no pollution; solar energy resources are widely distributed and inexhaustible. Therefore, compared with new power generation technologies such as wind power, biomass power generation and nuclear power, photovoltaic power generation is a renewable energy power generation technology with the most sustainable ideal characteristics (the richest resources and the cleanest power generation process). It has the following main advantages.

①The solar energy resources are inexhaustible and inexhaustible. The solar energy irradiated on the earth is 6000 times greater than the energy consumed by human beings. Moreover, solar energy is widely distributed on the earth. As long as there is sunlight, photovoltaic power generation systems can be used, not limited by factors such as region and altitude.

②Solar energy resources are available everywhere, and can be powered nearby, without long-distance transmission, to avoid the loss of electrical energy caused by long-distance transmission lines.

③ The energy conversion process of photovoltaic power generation is simple, which is the direct conversion from light energy to electric energy. There is no intermediate process (such as thermal energy conversion to mechanical energy, mechanical energy to electromagnetic energy, etc.) and mechanical movement, and there is no mechanical wear. According to thermodynamic analysis, photovoltaic power generation has a high theoretical power generation efficiency, which can reach more than 80%, and the technology development potential is huge.

④Photovoltaic power generation itself does not use fuel, emits any substances including greenhouse gases and other exhaust gases, does not pollute the air, does not generate noise, is friendly to the environment e799bee5baa6e78988e69d8331333337613766, and will not be affected by the energy crisis or the instability of the fuel market It is a new type of renewable energy that is truly green and environmentally friendly.

⑤The photovoltaic power generation process does not require cooling water, and can be installed on the desert Gobi without water. Photovoltaic power generation can also be easily combined with buildings to form a photovoltaic building integrated power generation system, which does not require separate land occupation and can save valuable land resources.

⑥ Photovoltaic power generation has no mechanical transmission parts, simple operation and maintenance, stable and reliable operation. A set of photovoltaic power generation system can generate electricity as long as there are solar cell modules, and the widespread use of automatic control technology can basically achieve unattended operation and low maintenance costs.

⑦The working performance of the photovoltaic power generation system is stable and reliable, and the service life is long (more than 30 years). The life of crystalline silicon solar cells can be as long as 20 to 35 years. In the photovoltaic power generation system, as long as the design is reasonable and the type selection is appropriate, the life of the battery can also be as long as 10 to 15 years.

⑧Solar cell module has simple structure, small volume and light weight, which is convenient for transportation and installation. The construction period of the photovoltaic power generation system is short, and the load capacity can be large or small according to the electricity consumption, which is convenient and flexible, and is easy to combine and expand.

Solar battery is a promising new power supply, with three advantages of permanence, cleanliness and flexibility. Compared with thermal power generation and nuclear power generation, solar photovoltaics do not cause environmental pollution; solar cells can be large, medium and small, and can be as large as one million kilowatts of medium-sized power stations, as small as an independent solar power system for only one household. These characteristics are unmatched by other power supplies.

(2) Disadvantages

Of course, solar photovoltaic power generation also has its shortcomings and shortcomings, summarized in the following points.

① Low energy density. Although the sum of the energy that the sun puts on the earth is extremely huge, but because the earth ’s surface area is also very large, and most of the earth ’s surface is covered by the ocean, the solar energy that can actually reach the land surface reaches only about 10% of the solar radiation energy in the earth ’s range, resulting in The amount of solar energy directly available in the area is small. Generally expressed in terms of solar irradiance, the highest value of the irradiance on the earth's surface is about 1.2kw / ㎡, and in most areas and most of the sunshine time is less than 1kw / ㎡. The use of solar energy is actually the collection and utilization of low-density energy.

②It covers a large area. Due to the low energy density of solar energy, this will make the photovoltaic power generation system occupy a large area. Every 10kw of photovoltaic power generation needs about 100 square meters, and the average power generation per square meter is 100w. With the maturity and development of photovoltaic building integrated power generation technology, more and more photovoltaic power generation systems can use the roofs and facades of buildings and structures, which will gradually overcome the shortage of large photovoltaic power generation area.

③ Low conversion efficiency. The most basic unit of photovoltaic power generation is a solar cell module. The conversion efficiency of photovoltaic power generation refers to the ratio of the conversion of light energy into electrical energy. At present, the conversion efficiency of crystalline silicon photovoltaic cells is 13% to 17%, and that of amorphous silicon photovoltaic cells is only 5% to 8%. Since the photoelectric conversion efficiency is too low, the photovoltaic power generation density is low, and it is difficult to form a high-power generation system. Therefore, the low conversion efficiency of solar cells is the bottleneck that hinders the widespread promotion of photovoltaic power generation.

④ Intermittent work. On the surface of the earth, the photovoltaic power generation system can only generate electricity during the day and cannot produce electricity at night. Unless there is no day and night in space, the solar cells can continuously generate electricity, which is inconsistent with people's electricity demand.

⑤ is greatly affected by climate and environmental factors. The energy of solar photovoltaic power generation directly comes from the sunlight, and the solar radiation on the earth's surface is greatly affected by the climate. Long-term rain and snow, cloudy, foggy, and even cloud changes will seriously affect the power generation state of the system. In addition, environmental factors also have a great influence. The more prominent point is that particles (such as dust) in the air settle on the surface of the solar cell module, blocking part of the light, which will reduce the conversion efficiency of the cell module. As a result, the amount of power generation is reduced and even the damage of the battery panel is caused.

⑥ Strong regional dependence. Different geographical locations and different climates make the sunshine resources vary greatly from region to region. Only when the photovoltaic power generation system is applied in areas with abundant solar energy resources will its effect be good.

⑦High system cost. Due to the low efficiency of solar photovoltaic power generation, the cost of photovoltaic power generation is still several times that of other conventional power generation methods (such as thermal power and hydropower), which is the most important factor restricting its wide application. However, it should also be noted that with the continuous expansion of solar cell production capacity and the continuous improvement of cell photoelectric conversion efficiency, the cost of photovoltaic power generation systems has also fallen very fast. The price of solar cell modules has dropped from more than US $ 70 per watt to about US $ 2 per watt in recent decades.

⑧ The manufacturing process of crystalline silicon battery is high pollution and high energy consumption. The main raw material of crystalline silicon battery is pure silicon. Silicon is an element on earth that is second only to oxygen, and its main form is sand (sio2). The step by step process from silica sand to crystalline silicon with a purity of 99.9999% or more requires multiple chemical and physical processes, which not only consumes a lot of energy, but also causes certain environmental pollution.