Drive more than 50 kilometers northeast from Gulang County to the southern edge of the Tengger Desert.
The Tengger Desert is the fourth largest desert in China, but the dunes are no longer tall or continuous on either side of the desert road, as they are cut off by blue photovoltaic panels.
Gulang County has abundant sunshine and solar energy is a resource area, with an average annual total radiation of 5,800-6,200 megajoules per square meter, about 2,880 hours of sunshine, and an average of 1,750 hours of effective utilization.
In recent years, Gulang County has closely followed the national "double carbon" strategic goal and focused on building a million-kilowatt photovoltaic power generation base in the northern sandy area. Today, endless photovoltaic panels stretch out in the Gobi, like sparkling ripples stretching into the sky, silently catching the blazing sun.
After drilling through the towering transmission towers, we came to the Gulang Power Station of Xinhua Power Generation. The first unit of the power station will be energized on April 8, 2023, and the full capacity will be connected to the grid for power generation on June 26. In addition, the power station also manages the Gulang Luzhou Photovoltaic Power Station and the Gulang Zhenye Photovoltaic Power Station. These three photovoltaic power stations are arranged in a zigzag shape in space, with a total installed capacity of 300,000 kilowatts and an annual power generation capacity of 4About 800 million kWh.
As soon as he got off the bus, Luo Jianjun, the stationmaster of the power station, couldn't wait to point to the photovoltaic power generation array in the distance.
Reporter, you must first take a look at our 'chasing the sun' photovoltaic panels, just like sunflowers, sticking to the sun. ”
How do photovoltaic panels "chase the sun"? "There are two modes, one that automatically adjusts by time and the other that is a 'two-horse-drawn cart'. Luo Jianjun said that some photovoltaic panels have two small photovoltaic modules on both sides, which can sense the direction and intensity of the sun's rays.
Entering the centralized control center of Xinhua Power Gulang Power Station, the background monitoring system composed of three rows of computers corresponds to the three photovoltaic power stations of Luzhou, Zhenye and Xincheng Baohua. The on-duty personnel can grasp the operation status of each unit and the spot transaction information in real time.
The usual job is the same as that of a trader. Chen Hao, the duty officer, said: "The photovoltaic electricity produced by the power station is finally remitted to the power trading platform of the provincial State Grid Company. As a seller, we provide different types and time periods of electricity, listed on the platform for trading, electricity prices will fluctuate in real time according to the power supply and demand situation at all times, and power stations can flexibly arrange power generation plans to save costs. ”
The so-called flexible arrangement is actually 'crest leveling'. Luo Jianjun explained that just like boiling a pot of water to prepare noodles for cooking, the key is to control the heat. The morning and evening rush hours correspond to the time of the day when everyone goes home to cook, turn on the air conditioner and other large amounts of electricity, at this time, the electricity demand of every household soars, so they have to turn on the fire to boil the water quickly; In the middle of the night or early morning, most people are resting, the demand for electricity is reduced, and only a small fire needs to be maintained. Power plants should "level their peaks" with large fluctuations in power demand between day and night, weekdays and weekends. At the same time, the energy storage system is used to smooth the output, so that the entire power supply and demand are balanced at all times, and avoid the waste of resources caused by the mismatch between supply and demand.
Along the towering overhead line, the reporter and his entourage came to the Yiheng Baohua photovoltaic power station not far away, and several large photovoltaic power stations nearby are using the energy storage battery compartment here to complete power storage.
Our 18 battery compartments are like large 'power banks'. Feng Liang, director of Yiheng Baohua photovoltaic power station, said that the electricity generated by photovoltaic panels is usually direct current, and for energy storage systems, the most widely used technology is lithium iron phosphate battery energy storage. The battery stores electrical energy through a chemical reaction between the positive and negative electrodes, and the current generated by this chemical reaction is also direct current, which is stable and safe.
Yiheng Baohua photovoltaic power station is also responsible for the daily operation and maintenance of the 330 kV convergence booster station in Huanghuatan. "The first batch of national large-scale base projects, the 300,000 kilowatt photovoltaic sand control project of Yili Group, and the 300,000 kilowatt of Jiayu Group and the 150,000 kilowatt of Xinhua Hydropower, the first batch of photovoltaic power in the province's '14th Five-Year Plan' new energy competition index projects, were brought together to generate electricity. Feng Liang said.
"Pooling" refers to the concentration of direct current generated by thousands of photovoltaic modules. Through the combiner box, the DC current output of all photovoltaic arrays will be pooled together in parallel or series to form a large DC current.
This is followed by the "boost" process. Since high voltage is beneficial in power transmission to reduce the loss of electrical energy in the transmission process, it is necessary to convert low-voltage direct current to high-voltage alternating current. At this stage, direct current is fed into the inverter, which converts the direct current into alternating current and raises the voltage to a high voltage level suitable for long-distance transmission.
Finally, the high-voltage alternating current enters the transformer, the core equipment of the booster station, and after further increasing the voltage, the clean solar power is transmitted to the grid or other power load centers through the transmission line to supply electricity to users or commercial electricity. It can be said that the convergence booster station is the energy center dotted in the "photovoltaic sea".
Treat in production, sand to make the best use. While making every effort to promote the development of the photovoltaic industry, Gulang County also takes into account the organic combination of photovoltaic power generation and ecological governance. Specific to the construction of major photovoltaic power generation bases, by raising the height of photovoltaic arrays, widening the spacing of arrays, using photovoltaic modules as vegetation shade, reducing evaporation, and promoting the growth and restoration of vegetation, it is conducive to the development of planting and aquaculture, realizing the output of clean energy and the efficient use of land resources, and turning the desert "no man's land" into a new "gold rush".
New Wuwei reporter Gan Yaoyu Yu Fang.