To estimate the power generation capacity of a photovoltaic power generation system, it is necessary to know the peak sunshine hours in the local installation area of the system (converting the total solar radiation received on the photovoltaic module surface into hours under irradiance of 1000W/m2), system efficiency, and system installation capacity.

For example, a 10kW photovoltaic grid connected system is installed in Beijing with a peak sunshine hour of 4 hours, and the efficiency of the photovoltaic grid connected system is about 80%. Therefore, the formula for calculating the daily power generation of the system=component installation capacity × peak sun hours × System efficiency=10 × four × 0.8=32kWh, approximately 32 kWh.

Photovoltaic power generation has significant energy, environmental protection, and economic benefits, and is one of the highest quality green energy sources.

Under the average sunshine conditions in China, installing a 1 kW distributed photovoltaic system can generate 1200 kWh of electricity per year, reduce the use of coal (standard coal) by about 400 kilograms, and reduce carbon dioxide emissions by about 1 ton.

According to research by the World Wildlife Fund (WWF), installing a 1 square meter photovoltaic power generation system is equivalent to planting 100 square meters of trees in terms of reducing carbon dioxide emissions. At present, the development of renewable energy such as photovoltaic power generation will be one of the effective means to fundamentally solve environmental problems such as haze and acid rain.

Photovoltaic power generation refers to the use of solar photovoltaic cells to directly convert solar radiation into electrical energy. Photovoltaic power generation is the mainstream of solar power generation today.

Distributed photovoltaic systems refer to photovoltaic power generation facilities that are built near user sites and generally connected to power grids with voltage levels below 35kV. The generated electricity is mainly consumed locally and is characterized by balanced regulation in the distribution system. There are two modes of operation for distributed photovoltaic systems: self use, surplus power grid connection, and full grid connection. Spontaneous self use and surplus electricity grid connection refers to the priority use of electricity generated by distributed photovoltaic power generation systems by power users, with excess electricity connected to the grid; Full grid connection refers to the complete connection of the electricity generated by the distributed photovoltaic power generation system to the power grid.

Distributed power generation follows the principles of adapting to local conditions, clean and efficient, decentralized layout, and nearby utilization, fully utilizing local solar energy resources to replace and reduce fossil energy consumption.

The distributed photovoltaic system combined with buildings is currently an important application form of distributed photovoltaic systems, with rapid technological progress, mainly manifested in the installation method combined with buildings and the electrical design of building photovoltaic systems. According to the different installation methods combined with buildings, it can be divided into photovoltaic building integration, building integrated PV (commonly known as BIPV), and photovoltaic building attachment (abbreviated as BAPV). The definition is as follows:

BIPV: A photovoltaic system that uses specially designed specialized photovoltaic modules to replace existing building materials or components during installation and integrate with the building. Removing photovoltaic modules will prevent the building from functioning properly. Photovoltaic modules not only need to meet the functional requirements of photovoltaic power generation, but also must first meet the basic functional requirements of the building, such as durability, insulation, waterproof and moisture-proof performance, appropriate strength and stiffness. Common ones include photovoltaic tiles, photovoltaic curtain walls, photovoltaic ceilings, photovoltaic windows, and photovoltaic sunshades or sunshades.

BAPV: A photovoltaic system that uses ordinary photovoltaic modules and is installed on existing buildings without replacing building materials or components. It is directly installed on the roof or attached to the wall. Removing the photovoltaic modules from this building will not affect the basic functions of the original building.

Household distributed photovoltaic system refers to a distributed photovoltaic system that utilizes buildings within the scope of natural person homesteads, such as self owned residential buildings and attachments. Household distributed photovoltaic systems typically have characteristics such as small installation capacity, low voltage level grid connection, simplified filing and grid connection processes.