What is the capacity of a PV power station if it is to be installed on a 1-m2 PV power station? How much does it cost? What is its generating capacity?
The roofs for installing PV power station for home use are generally divided into two types: flat roof and pitched roof. The pitched roof includes colorful steel plate roof and pitched roof for tile-roofed house. Generally, the photovoltaic module of each KW needs a roof area of 15 to 20 square meters. 10 to 15 square meters are needed for pitched roof.

Presently the price for installing PV power station is approx. 10 Yuan. If a user intends to install PV station onto his or her roof, the price can be subject to the above relation roughly.
For most families, installing a 3-5kW PV power generation system will meet the daily power consumption. The generating capacity of the PV system installed by each family will be impacted by different areas. The different installation angle and devices as well as the change of illumination will lead to differences to the actual generating capacity of a system. If a user intends to achieve higher cost performance, rational and optimized matching is needed.
Taking the 3 KW PV power station as an example, we have summed up the daily generating capacity of the 3 KW systems all over China. Refer to the cities nearby.

Application scope of distributed PV power station
Distributed PV power station, also referred to as distributed power generation or distributed energy supply, has independent systems which can act on self-operated control and exhibit high safety. The product has seen rapid development in recent years.

1. Mode of application of distributed PV power station
① Grid:The grid-based distributed power generation is mostly used near the user and generally functions by grid-connected operation with medium and low voltage distribution network. The power is generated for the user’s own consumption. When the power fails to be generated or when the power is insufficient, users can purchase electricity from the power grid. When the electricity is excessive, users may sell the power via the internet.
② Off-grid type:The off-grid distributed PV power station is generally applied to remote areas and islands. Without connection with large power grids, it directly supplies electricity to load by virtue of its intrinsic power generation system and energy storage systems.
③ Multifunctional complementary microgrid:Distributed PV system can also function as multifunctional complementary micro electrical system with other modes of power generation, such as water, wind and light. It can both operate independently as microgrid and connect with the power grid for networking. Presently great attention has been paid to China’s wind and light complementary project.

2. Field of application
Distributed PV power generation system is applicable to the following two areas.
① It can be popularized to various buildings and public facilities nationwide, thus allowing the distributed PV power generation system for buildings to take shape. By virtue of the local buildings and public facilities, distributed power generation system has been constructed to meet some of the needs of power consumers and to supply electricity for production to high energy-consuming enterprises.
② This system can be popularized in remote areas, islands and other areas that are lack of and absent of electricity, thus bringing about off-grid power generation system or microgrid. Owing to differences in economic level, the power consumption for basic use has not been addressed in some of the remote areas of China. Most rural electric engineering in the past relies on extended large power grids and the power supply from small hydropower stations and small thermal power stations, etc. The great difficulty in grid extension and the overlength power supply radius lead to inferior power supply quality. Development of off-grid distributed power generation can not only offer electricity for the basic use of residents in areas lack of and absent of electricity, but also may utilize the local renewable energy sources in a clean and efficient way. In this way, the contradiction between energy and environment can be solved effectively. In 2016, the Chinese government promulgated several policies to boost the development of “poverty relief through photovoltaic project”, which is based on the advantage in photovoltaic power generation.

3. Places fit for installation of distributed PV power generation system
① Industrial workshops:Photovoltaic array is fit to be installed to factories with higher power consumption and high online electric charge, because such factories usually have large roof area and the roof is wide and smooth. As a result of higher electrical load, distributed PV grid-connection system can offset part of the electricity purchased online and thus save the electric charge for users.
② Commercial buildings:The function and effect are similar to that of the industrial parks. The differences are that most commercial buildings have cement roof which is more suitable for installing PV array. But buildings usually need to be more attractive. According to the characteristics of commercial buildings, office buildings, hotels, conference centers, holiday villages and other places, users usually consume higher electricity at daytime, and the power consumption at night is lower, which is more compatible with the characteristics of photovoltaic power generation.
③ Agricultural facilities:There are a large number of roofs in rural areas, including residences, vegetable greenhouses, fishponds and so on. As most rural areas are located at the end of the public power grid, the electricity quality is relatively on the low side. Consequently, construction of distributed PV system will help guarantee power consumption and quality in a more effective way.
④ Municipal works and other public buildings:Owing to standard and uniform management, relatively reliable load and commercial behaviors of users, and their great enthusiasm in installation, distributed PV facilities are also fit to be installed for municipal works and other pubic buildings in a concentrated way and in large areas.
⑤ Remote agricultural and pastoral areas: Owing to the great distance to the power grid, there are millions of people that have no access to electricity in the remote pasturing areas in Xizang, Qinghai, Xinjiang, Inner Mongolia, Gansu and Sichuan as well as China' offshore islands. The off-grid PV system or other micro-grid power generation systems with energy supplementation are highly suitable to be used in these areas.

4. Distributed PV power generation system in combination with buildings
The PV power generation system in combination with buildings is the main application method for the current distributed PV power generation. The related technologies have witnessed rapid development in terms of the installation method combined with buildings and the electrical design of building photovoltaic system. Based on the different installation methods in combination with buildings, the system can be divided into PV building integration and PV building additions.

5. Differences between the installation of PV array at the facade and on the roof of buildings
The modes of integration between PV array and buildings are divided into installation at the facade and on the roof, both of which are suitable for most of the buildings.

The form of installation on the roof includes horizontal roof, slanting roof and PV daylighting roof.

A. The PV array on the horizontal roof can be installed according to the optimum angle in order to obtain the maximum generating capacity. Additionally, regular crystalline silicon PV modules can be applied to bring down cost for modules. Despite its competitive price, such mode of installation is not attractive enough.
B. PV array can be installed to slanting roofs to the due south, southeast, southwest, due east or due west of the Northern Hemisphere. For slanting roofs in due south, PV array can be installed according to the optimum orientation or the one most approximate to the optimum orientation.
C. PV daylighting roof refers to the building components that employ the transparent photovoltaic cells as daylighting roof. The roof is pretty attractive and pervious to light. But PV daylighting roofs need transparent components which are rather low in efficiency. Except that the power generation components are transparent, components for the daylighting roof must meet the requirements on mechanics, aesthetics, structural connection and other building-related aspects. As a result, the cost for both the modules and power generation is relatively higher.
Installation at side elevation mainly refers to install PV module on the south, west and east door of the buildings. For high-rise buildings, wall is the external surface with the largest area exposed to the sun. PV curtain wall is a mode of application that is has come into relative popular use.