What is photovoltaic power generation and what is distributed photovoltaic power generation?

1.What is photovoltaic power generation and what is distributed photovoltaic power generation?

Photovoltaic power generation refers to the power generation method that directly converts solar energy into electrical energy. Photovoltaic power generation is the mainstream of solar power generation today. Therefore, solar power is often referred to as photovoltaic power generation.

Photovoltaic distributed power generation is a new type of power generation and comprehensive utilization of energy with broad prospects for development. It advocates the principles of nearby power generation, nearby grid connection, nearby conversion, and nearby usage principles, which can not only effectively increase the power generation capacity of photovoltaic plants of the same scale. At the same time, it also effectively solves the problem of power loss during boosting and long-distance transportation. However, distributed power generation also has strict requirements on how to maximize the amount of solar power generation and how to ensure the security of the power grid. In this process, the functionality and stability of photovoltaic inverters are also extremely critical. Distributed power generation follows the principles of adapting to local conditions, clean and efficient, decentralized layout, and nearby utilization, making full use of local solar energy resources to replace and reduce fossil energy consumption.

The distributed generation grid connection method can be "spontaneous use, the remaining electricity is connected to the grid", or it can be "purchased and sold collectively" (sold to the grid in full).

2.Do you know the historical origin of photovoltaic power generation?

In 1839, when 19-year-old French Becquerel did a physical experiment, it was found that when two metal electrodes in a conductive liquid were irradiated with light, the current would increase, thereby discovering the "photovoltaic effect". In 1930, 郞 Ge first proposed to use the "photovoltaic effect" to make solar cells, so that solar energy into electricity.

In 1932 Audubert and Stora made the first "cadmium sulfide" solar cell.

In 1941 Audu discovered the photovoltaic effect on silicon.

In May 1954, the United States Bell Labs Chibabin, Fuller, and Peel released a monocrystalline silicon solar cell with an efficiency of 6%. This was the world's first solar cell of practical value. In the same year, Wick discovered arsenic Nickelization has a photovoltaic effect, and a nickel sulfide film is deposited on the glass to make a solar cell. A practical photovoltaic power generation technology that converts sunlight into electrical energy was born and developed.

In early 2014, in order to implement the new requirements of the provincial party committee and government for targeted poverty alleviation, Jinzhai County implemented industrial poverty alleviation “to the village, to the household, to the people, to the industry” and took the lead in launching photovoltaic power poverty alleviation projects in the province.

3.How does a photovoltaic cell generate electricity?

Photovoltaic cell is a kind of semiconductor device with light and electricity conversion characteristics. It directly converts solar radiation energy into direct current. It is the most basic unit of photovoltaic power generation. The unique electrical characteristics of photovoltaic cells are obtained by incorporating certain elements Element (such as phosphorus or boron, etc.), which causes permanent imbalance in the molecular charge of the material, forming a semiconductor material with special electrical properties, and free electrical charges can be generated in a semiconductor with special electrical properties under sunlight Directional movement and accumulation, so that electricity is generated when its two ends are closed. This phenomenon is called "photovoltaic effect" or photovoltaic effect for short.

4.What components does a photovoltaic power generation system consist of?

Photovoltaic power generation system consists of photovoltaic square array (photovoltaic square array composed of photovoltaic modules in series and parallel), controller, battery pack, DC / AC inverter, etc. The core components of photovoltaic power generation system are photovoltaic modules, and It is made up of photovoltaic cells in series, parallel, and packaged. It directly converts solar light energy into electricity, and the electricity generated by photovoltaic modules is DC. We can use it or use an inverter to convert it to AC power for use. From a perspective, the electrical energy generated by the photovoltaic system can be used immediately, or it can be stored with energy storage devices such as batteries, and released at any time as needed.

Equipped with energy storage devices such as batteries will greatly increase the cost of photovoltaic power generation systems. Except for special purposes, it is generally not appropriate to promote them.

5.Why is photovoltaic power a green and low-carbon energy source?

Photovoltaic power generation has significant energy, environmental protection and economic benefits. It is one of the highest quality green energy sources. A 1 kW photovoltaic power generation system is installed under the average sunshine conditions in China, which can generate 1,200 kWh of electricity per year, which can reduce the use of coal (standard coal). The amount is about 400 kg, and carbon dioxide emissions are reduced by about 1 ton. According to the results of the World Wide Fund for Nature (WWF), installing a 1-square-meter photovoltaic power generation system is equivalent to planting a tree for 100 square meters. Energy is one of the effective means to fundamentally solve environmental problems such as haze and acid rain.

6. How to treat the news that it consumes a lot of energy when producing photovoltaic cell modules?

Photovoltaic cells do consume a certain amount of energy in their production process, especially in the three links of industrial silicon purification, high-purity polysilicon production, single-crystal silicon rods and polysilicon ingot production, but the service life of photovoltaic cells in 20 years During the period, energy can be continuously generated. It is estimated that under the average sunshine conditions in China, the energy return of a photovoltaic power generation system over its life span exceeds 15 times its energy consumption. The energy recovery period of a 1 kW rooftop photovoltaic grid-connected system installed in Beijing with the best inclination angle is 1.5-2 years, which is far less than the service life of the photovoltaic system. That is to say, the electricity generated by the photovoltaic system in the first 1.5-2 years is used to offset the energy consumed in its production and other processes. The energy emitted after 1.5-2 years is pure output, so the photovoltaic cells should be evaluated from the perspective of the entire life cycle. Energy consumption.

7. How to treat the news that there is a lot of pollution in the production of photovoltaic cell modules?

The production of photovoltaic cell modules includes several industrial chain links including polysilicon, silicon ingot wafers, photovoltaic cells and photovoltaic modules. Related pollution reports mainly refer to the raw materials of photovoltaic modules, by-products produced in the production of high-purity polysilicon, and the production of high-purity polysilicon. The modified Siemens method is mainly used to convert metallurgical grade silicon into trichlorohelium silicon, which is reduced to hydrogen-grade polysilicon when hydrogen is added. In addition, silicon chloride is formed as a by-product. Silicon tetrachloride decomposes into silicic acid when it is exposed to humid air. And hydrogen chloride, if it is not handled properly, it will cause pollution problems, but the modified Siemens method adopted by China's polysilicon production enterprises can already achieve closed-loop production, recycling by-products of silicon tetrachloride and tail gas to achieve clean production. In December 2010, the State issued the "Access Conditions for the Polysilicon Industry", which stipulates that the recovery and utilization rate of silicon tetrachloride and chlorine in the reduction tail gas is not less than 98.5% and 99%. Therefore, the mature and improved Siemens method production technology fully meets environmental protection requirements. No environmental pollution problems.

8. How much sunlight do we have? Can it become the dominant energy source in the future?

The solar radiation received on the earth's surface can meet 10,000 times the global energy demand. The average annual radiation received per square meter on the earth's surface varies between regions by about 1000-2000KWH. According to IEA data, 4% of the world ’s deserts Installing solar photovoltaic systems on it is enough to meet global energy demand. Solar photovoltaic enjoys broad development space and its potential is huge.

According to preliminary statistics, China ’s market potential of using only existing buildings to install photovoltaic power generation is about 3 trillion kilowatts or more. In addition to the vast Gobi photovoltaic power generation market in the west, the potential is more than several billion kilowatts. Technological progress and large-scale applications will further reduce the cost of power generation, becoming a more competitive energy supply method, gradually from supplementary energy to alternative energy, and hope to become the dominant energy source in the future.