BroVolt

How to calculate the efficiency of PV system?

Time :2024-11-06 Author :Brovolt Scanning :
Photovoltaic system efficiency (Performance Ratio, PR) is an important concept in the photovoltaic industry. It includes the aging attenuation efficiency of solar cells and components, AC/DC low-voltage system losses and other equipment aging efficiency, inverter conversion efficiency, transformer and grid loss efficiency.

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Photovoltaic system efficiency (Performance Ratio, PR) is an important concept in the photovoltaic industry. It includes the aging attenuation efficiency of solar cells and components, AC/DC low-voltage system losses and other equipment aging efficiency, inverter conversion efficiency, transformer and grid loss efficiency. System efficiency is generally calculated by the following formula:

System efficiency PR=Energy generation in a certain period of time E/(Photovoltaic system capacity P*peak sunshine hours in a certain period of time)

The main factors affecting system efficiency are:

The average power attenuation of photovoltaic components is about 1% per year, and the Chinese national standard requires that the power attenuation within 20 years is not more than 20%;

The series-parallel loss of photovoltaic strings is about 0.5%;

The average loss of dust and snow is 4%~5%;

The average temperature coefficient loss of photovoltaic components is about 4%;

The DC cable connection loss is about 2%;

The AC cable connection loss is also about 2%;

The efficiency of photovoltaic inverters is 97%~97.5%;

The efficiency of step-up transformers is 98%.

Therefore, the overall efficiency of a photovoltaic power generation system is generally between 80% and 82%, rather than the attenuation efficiency of photovoltaic modules or the conversion efficiency of photovoltaic inverters as some people believe.