How to effectively increase the power generation of solar power plants?

How to effectively increase the power generation of solar power plants?

The calculation method of solar power generation capacity is as following:

Theoretical annual power generation = total annual average solar radiation * total solar cell area * photoelectric conversion efficiency

However, due to various factors, the power generation of solar power plants is actually not that much,

Actual annual power generation = theoretical annual power generation * actual power generation efficiency

So what are the factors that affect the power generation of solar power plants, let's find out!

1. The amount of solar radiation

A solar panel is a device that converts solar energy into electrical energy, and the intensity of light radiation directly affects the amount of electricity generated. The solar radiation data of each region can be obtained through the NASA meteorological data query website, or with the help of solar design software such as PV-SYS and RETScreen.

2. The inclination angle of the solar panel

The data obtained from the weather station is generally the amount of solar radiation on the horizontal plane, which can be converted into the amount of radiation on the inclined plane of the solar array to calculate the power generation of the solar system. The optimal inclination is related to the latitude of the project location. The approximate experience values are as follows:

A. Latitude 0°～25°, the inclination angle is equal to the latitude

B. Latitude is 26°～40°, and the inclination is equal to latitude plus 5°～10°

C. Latitude is 41°～55°, and the inclination is equal to latitude plus 10°～15°

3. Conversion efficiency of solar panel

solar modules are the most important factor affecting power generation. On February 5, 2015, the General Department of the National Energy Administration issued the "Letter on Solicitation of Opinions on Playing the Market Role to Promote solar Technology Progress and Industrial Upgrading", which stipulates that since 2015, the solar modules and Grid-connected inverter products should meet the requirements of the relevant indicators of the "Conditions for the solar Manufacturing Industry". Among them, the conversion efficiency of polycrystalline silicon solar panel is not less than 15.5%, and the conversion efficiency of monocrystalline silicon solar panel is not less than 16%. At present, the conversion efficiency of polycrystalline silicon modules of first-line brands on the market is generally above 16%, and the conversion efficiency of monocrystalline silicon is generally above 17%.

4. System Loss

Like all products, solar power plants have a life cycle of up to 25 years, the efficiency of components and the performance of electrical components will gradually decrease, and the power generation will decrease year by year. In addition to these natural aging factors, there are also various factors such as the quality of components and inverters, circuit layout, dust, series-parallel loss, and cable loss.

In the financial model of a general solar power station, the power generation of the system decreases by about 5% in three years, and the power generation decreases to 80% after 20 years.

(1). Combined loss

Any series connection will cause current loss due to the current difference of the components; parallel connection will cause voltage loss due to the voltage difference of the components; and the combined loss can reach more than 8%, and the China Engineering Construction Standardization Association standard stipulates that it is less than 10%.

Therefore, in order to reduce the combined loss, attention should be paid to:

1) The components with the same current should be strictly selected and connected in series before the installation of the power station.

2) The attenuation characteristics of the components are as consistent as possible.

(2). Dust cover

Among all the various factors that affect the overall power generation capacity of solar power plants, dust is the number one killer. The main impacts of dust solar power plants are:

1) By shading the light reaching the module, thereby affecting the power generation;

2) Affect heat dissipation, thereby affecting conversion efficiency;

3) The dust with acidity and alkalinity is deposited on the surface of the module for a long time, which erodes the board surface and causes the board surface to be rough and uneven, which is conducive to the further accumulation of dust and increases the diffuse reflection of sunlight.

Therefore, the components need to be wiped clean from time to time. At present, the cleaning of solar power plants mainly includes three methods: sprinkler, manual cleaning, and robot.

(3). Temperature characteristics

When the temperature rises by 1℃, the crystalline silicon solar cell: the maximum output power decreases by 0.04%, the open circuit voltage decreases by 0.04% (-2mv/℃), and the short circuit current increases by 0.04%. To reduce the effect of temperature on power generation, the modules should be well ventilated.

(4). Line and transformer loss

The line loss of the DC and AC circuits of the system should be controlled within 5%. For this reason, a wire with good electrical conductivity should be used in the design, and the wire needs to have a sufficient diameter. During system maintenance, special attention should be paid to whether the connectors and terminals are firm.

(5). Inverter efficiency

Due to the presence of inductors, transformers, and power devices such as IGBTs and MOSFETs, the inverter will generate losses during operation. The general string inverter efficiency is 97-98%, the centralized inverter efficiency is 98%, and the transformer efficiency is 99%.

(6). Shadow and snow cover

In a distributed solar power plant, if there are tall buildings around, it will cause shadows to the components, and should be avoided as much as possible in the design. According to the circuit principle, when the components are connected in series, the current is determined by the least block, so if there is a shadow on one block, it will affect the power generation of the components. When there is snow on the components, it will also affect the power generation and must be removed as soon as possible.