Centralized photovoltaic

2024-08-01

Centralized photovoltaics is a large-scale ground power station constructed using vacant land and solar energy resources in sparsely populated areas, and is currently the most important form of photovoltaic market in China.

Working principle: The centralized photovoltaic power generation system converts solar energy into direct current energy through a large number of solar panels, and then converts the direct current energy into alternating current energy through an inverter. After the electrical energy is boosted to the appropriate voltage level through a step-up transformer, it is connected to the high-voltage transmission system and uniformly configured by the power grid to deliver the electrical energy to distant users.

Main component: Photovoltaic module: It is one of the most important components of centralized photovoltaic power plants, which converts solar energy into direct current, accounting for about 44% -47.09% of the total investment in photovoltaic projects. At present, the main component manufacturers in the market include LONGi Green Energy, JinkoSolar, and Trina Solar.

Photovoltaic bracket: Structurally, it can be divided into three types: fixed bracket, adjustable tilt bracket, and tracking bracket. The cost of brackets accounts for about 5% -10% in photovoltaic projects, and currently fixed brackets are still the mainstream product.

Photovoltaic inverter: Its basic function is to convert the direct current generated by photovoltaic modules into alternating current that meets the requirements. It also has higher-level functions such as MPPT technology, which can generate more electricity under the same conditions and improve the system's power generation efficiency, accounting for about 10% of the cost of photovoltaic systems.

Photovoltaic transformer: Its main function is to boost the voltage, which is collected from the inverter (usually 800V) to 11kV, 32kV, 220kV, and even 800kV, in order to reduce line losses during power transmission and is suitable for long-distance transmission. The proportion of its cost is closely related to the specifications of the power grid and equipment selection.

Photovoltaic cables: mainly used for transmitting electricity, accounting for approximately 1% -1.5% of the cost of photovoltaic projects.

Energy storage system (optional): Photovoltaic power generation has instability, such as not generating electricity during the day or being affected by cloudy weather conditions, which can easily cause impact on the power grid. Energy storage systems can balance the output fluctuations of photovoltaic power plants, mainly divided into physical energy storage (such as flywheel energy storage, compressed air energy storage, pumped storage) and chemical energy storage (such as chemical battery energy storage, mainly including sodium ion batteries, ternary lithium batteries, and lithium iron phosphate batteries).

High power generation efficiency: Due to the large scale of centralized photovoltaic power stations, more advanced technology and equipment can be adopted to achieve higher power generation efficiency.

Convenient for centralized management: relatively easy to achieve unified monitoring, maintenance, and management, reducing operating costs.

Can leverage economies of scale: can achieve optimized allocation of resources on a large scale and reduce unit costs. It can fully utilize the positive peak shaving characteristics of solar radiation and electricity load, play a role in peak shaving, and operate flexibly. Compared with distributed photovoltaics, it is more convenient to control reactive power and voltage, and it is also easier to participate in grid frequency regulation