Photovoltaic is on fire again! Solar panels are installed in 1% of China’s deserts, or is it a solution to power shortages and limited production?
Photovoltaic solar panels
Electronic enthusiasts network reported (article/Huang Shanming) Recently, the sudden shortage of electricity in mainland China to limit production has caused a certain impact on many manufacturers with high energy consumption. The time period during which this round of power rationing occurred was not the peak season of power consumption, but the off-season. Facts have also proved that the lack of power and production is mainly caused by insufficient coal production and increased production of high energy consumption. Nowadays, coal-based thermal power accounts for about 70% of the total power generation. To change this situation, the development of other energy sources is necessary, and photovoltaics is one of the good choices.
In addition to thermal power, the current domestic power generation structure includes hydropower, nuclear power, wind power and solar power. From the perspective of total power generation in the country, thermal power will account for 68.5% in 2020, hydropower 17.4%, and nuclear power 4.7%. Wind power accounted for 6% and solar power accounted for 3.4%.
2011-2020 National Power Generation Structure
In terms of proportion, domestic thermal power is still dominated, but it can be found that although solar power has the lowest proportion, in terms of growth rate, from 600 million kwh in 2011 to 261.1 billion kwh in 2020, an increase of 434 in ten years Times.
In addition, hydropower is affected by the environment (larger rivers are required), and the investment is huge (the construction of hydroelectric power stations also requires the construction of dams), and the power output also depends on the water flow. In the construction of water conservancy projects for decades Next, there are fewer and fewer areas to choose from.
Nuclear power also requires strict site selection, especially the first three generations of nuclear power plants, which require a large amount of flowing water, and at the same time, they need to choose plain areas and cannot be built in mountains and forests. However, as the fourth-generation nuclear power plants have begun to operate in Gansu and other places, getting rid of the restriction of requiring large amounts of water resources, nuclear power will also become the main source of electricity in the future.
Wind power and photovoltaics have become the representatives of clean energy at present. However, for wind power, the instability of power generation has caused many grid companies to dislike it and become a waste of electricity. Usually there is electricity when there is wind, but there is no electricity if there is no wind. If you can find a suitable one The new energy storage method can solve the problem of wind power, which will be discussed later.
Photovoltaic mainly relies on solar energy. The problem is that it can only generate electricity during the day, but nowadays the peak of electricity consumption is usually during the day. It is good to supplement photovoltaics as an effective source of electricity. In addition, photovoltaics also have the same abandonment problem as wind power. Here is the table below.
Desert construction photovoltaic pollution controllable
Since the main energy of photovoltaic comes from the sun, it is natural to hope that the longer the sunshine time is, the better. If the sunshine time is long enough and there are more sunny days, and the terrain is flat and convenient to receive sunlight, it is also a suitable scene for photovoltaic power generation. It just so happens that the desert is particularly suitable for the use of photovoltaics.
The total desert area in China is about 1.3 million square kilometers, and 1% of the area is 13,000 square kilometers. Then these places are covered with photovoltaic panels. According to Wang Chuanfu, is the power generation enough?
Judging from the current data, the power per square meter is 150w. If calculated according to the sunshine time of 10 hours a day, the power generation of 13,000 square kilometers will reach 1.95 billion kW, and the annual power generation will reach 5.1 trillion kWh. We must know that China's installed power generation capacity will be 2.2 billion kW in 2020, and the difference between the two is not much.
According to public data, in 2020, the total power generation in mainland China will reach 7.7791 trillion kwh, which has accounted for 29% of the world's total. The construction of photovoltaic power generation covering 1% of the domestic desert area can reach 65.5% of the country's total power generation in 2020. Roughly speaking, it is not wrong that 1% of the desert area is sufficient for the whole country.
After all, there will be a variety of power generation methods in the country in the future. Today's thermal power generation is purely a last resort. The main reason is that coal power generation is the most economically stable method. However, once the current coal supply is insufficient, it will lead to shortages. Electric phenomenon occurs.
On the other hand, there are often rumors in the market that the photovoltaic industry is a high-pollution and high-energy-consuming industry, especially the large number of pollutants in the production process of photovoltaic crystalline silicon modules, mainly silicon tetrachloride (a highly polluting and highly toxic waste liquid) And hydrogen, chlorine, etc.
However, it is necessary to distinguish the difference between pollutants and environmental pollution. Only when the pollutants are not properly treated can pollution be caused. This also means that if the pollutants can be properly disposed of, it will not cause pollution.
Photovoltaic manufacturing mainly includes crystalline silicon purification, silicon ingot slicing, photovoltaic cells and photovoltaic modules. The crystalline silicon purification is to extract solar-grade crystalline silicon from industrial silicon powder, and then the crystalline silicon is processed by cutting, etching, cleaning, The printed electrodes are manufactured into photovoltaic cells, and then the cells are packaged into the final photovoltaic module. The so-called "high pollution" is in this ring.
In the purification of crystalline silicon, manufacturers usually adopt modified Siemens production process. During the production process, silicon tetrachloride, hydrogen, chlorine, etc. will be produced. If silicon tetrachloride is directly discharged, it will decompose to form hydrogen chloride when it encounters moist air. Cause environmental pollution.
However, various domestic crystalline silicon production enterprises have realized closed-circuit production, from synthesis to distillation, and then from reduction to tail gas separation, and have realized recycling, avoiding the leakage of polluting gases, so the pollution of photovoltaic production is generally controllable.
Improve desert ecology and win-win
In the actual application of photovoltaic power generation, the power generation is usually affected by the intensity and angle of sunlight, especially in different climates and seasons, the changes will be obvious, and the randomness is also strong.
As a result, when the electricity generated by the power station is input into the grid, there will be problems such as random intermittent input impacting the grid, and reverse peak shaving will increase the difficulty of grid peak shaving, which will affect the smooth operation of the entire grid.
According to statistics, in the first half of 2016, the northwestern region, which has the richest sunlight resources, had a serious abandonment problem. The amount of abandoned solar power reached 3.28 billion kwh, and the abandonment rate was 19.7%. The abandonment rate in Xinjiang even reached 52% at one time. .
However, by 2020, the problem of solar abandonment has been greatly improved. In the second quarter of 2020, the utilization rate of photovoltaic power generation has reached 98.6%, and the amount of solar abandonment nationwide is 1.03 billion kwh, a year-on-year decrease of 24.3%. Especially now that the country is vigorously advocating the development and construction of distributed photovoltaic power plants, the frequency of photovoltaic power curtailment is getting lower and lower.
Not only is the pollution controllable, and the rate of abandonment is gradually decreasing. The construction of photovoltaic power stations in the desert environment, with a dry climate and low rainfall, can also obtain better light intensity, and can effectively improve the desert environment and turn the desert into an oasis.
Generally speaking, there are two main reasons for the formation and persistence of deserts, one is the lack of water, and the other is the movement of sand dunes. According to public statistics, the photovoltaic panel shielding direct sunlight effectively reduces the evaporation of surface water. The shading effect of the photovoltaic panel can reduce the evaporation by 20%-30%, and the photovoltaic panel can also effectively reduce the wind speed.
Not only did it increase moisture, but while building the photovoltaic power station, it also fixed the sand dunes below so that they would no longer move. In this case, as long as the desert encounters precipitation, there will be plant growth, and the growth of plants will also produce water conservation effects, and finally this area will be filled with grassland that has become lush.
However, growing plants too high will also affect the normal power generation efficiency of photovoltaics. At this time, weeding is necessary. However, it is a pity to simply remove the grasses. Therefore, many photovoltaic power plants also come with some agricultural and animal husbandry products. , Such as planting fruits and vegetables under the photovoltaic power station, or raising sheep so that they can eat the weeds under the photovoltaic power station.
This not only forms an ecological cycle, but also improves the local desert environment. Through the conversion of solar energy into electric energy, the agricultural and animal husbandry products of photovoltaic power stations can also bring certain economic benefits. The additional products of certain power stations have surpassed that of desert photovoltaics. The cost of photovoltaic power plants has also greatly reduced the operation and maintenance costs of photovoltaic power plants.
summary
As the country puts forward the strategic goal of carbon neutrality, low energy consumption and clean energy will be the inevitable direction in the future. Especially in the previous period of power shortage and limited production, it is precisely because of the high proportion of thermal power that the coal supply will fluctuate slightly. Caused by insufficient electricity supply. Photovoltaic is a clean energy source, with controllable pollution and low abandonment rate, and it can also improve the desert environment. Photovoltaic + desert will be a huge emerging market.
