Are wind and photovoltaic "junk electricity"?

This year marks the beginning of the 14th Five-Year Plan. Wind power and photovoltaic power generation have also entered a new stage of development. The goal is to achieve the goal of "carbon peak and carbon neutral", and the proportion of non-fossil energy in primary energy consumption should reach 25% by 2030, and the total installed capacity of wind and solar power should reach over 1.2 billion kW. This year, wind power and photovoltaic power generation will account for about 11% of China's total electricity consumption, and this will increase year by year.

In May this year, the National Energy Administration issued a Notice on the Development and Construction of Wind and PHOTOVOLTAIC Power generation in 2021, which provides requirements, guidelines and guarantees for the commencement and construction of various wind and photovoltaic power projects.

How do wind and photovoltaics turn into electricity? What are the siting requirements for wind and photovoltaic power plants? How will new energy generation develop in the future?

Two principles of power generation

Wind power converts wind energy into mechanical energy, which is then converted into electrical energy. General wind power used by the windmill installed three impeller. After the wind blows the impeller, the rotation of the impeller drives the rotation of the generator, which generates electricity, which is ultimately sent to the power grid through the booster system for public use.

Photovoltaic power stations use solar panels to collect solar energy and convert it into electricity. Photovoltaic power generation mainly uses "photovoltaic effect". In simple terms, "photovoltaic effect" refers to the electromotive force of an object due to the absorption of photons. When the object is illuminated, the distribution of charge in the object will change, resulting in electromotive force and electric energy. In photovoltaic power station, solar panels, after exposure to the sun rays of the p-n junction in the photovoltaic cells (with different doping process, through the diffusion effect, the p-type and n-type semiconductor semiconductor production on the same piece of semiconductor substrate, forming space charge in their interface area called the PN junction) between the electronic flow, The flowing charge is collected to produce electricity.

Are wind and photovoltaic "junk electricity"?

There is volatility in both wind and photovoltaic power generation. Wind power generation will be affected by wind, wind speed and other factors; Photovoltaic power plants, on the other hand, do not work at night and lack sunlight to produce photovoltaic effects. Some people consider wind and photovoltaic power as "garbage electricity".

Although both have their weaknesses, Liu Jianping, deputy general manager of The Fujian branch of China Three Gorges Corporation, disagrees with the term "garbage electricity". "Wind and photovoltaic power are more environmentally friendly than traditional power generation, and we can equip wind and photovoltaic power plants with energy storage facilities to make new energy generation more stable," he said.

How to locate

First, adhere to the principle of environmental protection, site selection needs to avoid nature reserves, water protection areas, farmland, woodland and other places.

Second, choose a place rich in wind and light resources. Wind farms need to avoid areas with too little wind as well as too much. The wind is too small to drive the impeller rotation, only the wind speed of 3 m/s can drive the fan rotation. But too much wind will make the generator speed too high, heat out of control may lead to fire accidents.

Third, the location of wind power stations and photovoltaic power stations also have certain requirements on terrain. Wind farms are best located in tuyere or offshore. The sea level is relatively flat and the sea surface friction coefficient is small, and the wind is strong. Photovoltaic power stations also need to be located in flat areas with good construction conditions to facilitate the laying of photovoltaic panels in large areas. China's photovoltaic power stations are mostly built in the northwest, which is due to the fact that some areas in the northwest are flat, without the shelter of high-rise buildings and other buildings, so photovoltaic panels can fully absorb sunlight.

Unlike wind farms, photovoltaic plants are not currently built offshore on a large scale. The wind and wave resistance and corrosion resistance of photovoltaic power stations need to be further improved. However, Liu jianping said that there are many domestic manufacturers working on floating offshore photovoltaic power plants.

China's coastal areas have many factories and large electricity consumption, so the development potential of offshore PHOTOVOLTAIC power plants is huge.

China's new energy power generation industry started relatively late compared with European and American countries. In the early stage of the development of China's new energy power generation industry, many advanced technologies and products from Europe and America were introduced. After long-term development, China has completed the independent construction of new energy power generation industry and product system. China's new energy power generation industry needs to develop towards lower cost, higher intelligence and higher conversion rate in the future.

In the future, new energy generation mode will occupy the main position of power generation mode in China. Liu jianping said China is vigorously developing the new energy power generation industry and its installed capacity is growing fast. By the end of September, installed wind power was up 32.8 percent year on year, while installed photovoltaic power was up 24.6 percent. In the future, it will further expand the installed capacity of wind power and photovoltaic, and is expected to achieve the dominant position of new energy power generation by 2030, and strive to achieve the goal of "carbon peak and carbon neutrality".

Although the field of new energy power generation is still dominated by wind power generation and photovoltaic power generation, China is also studying other new energy power generation methods such as tidal power generation, hydrogen power generation and geothermal power generation. Liu said he expects more and more clean energy to be added to the grid in the future.

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