Many people must say that the development of distributed photovoltaics is good. Distributed photovoltaics are good. They say that the potential of distributed photovoltaic resources in China is huge, but how large is it, how many roof photovoltaics can be installed technically? How can distributed photovoltaics account for the future energy structure in China? What proportion of these issues are few people can say clearly. This issue is unclear and the road is unknown. It only stays on the concept. There is no detailed basic data support. The government's planning and policies are on paper and there is no foundation. The biggest problem here is not knowing how many rooftops in the country can install photovoltaics. The roof area is one of the main factors that determine the amount of PV installed in a building. However, no authoritative organization has conducted a comprehensive survey of the roof area of ​​the country.
In view of this, we have adopted a measure of “have no other choice†and used existing statistical data to estimate the roof area of ​​the nation’s available residents, and then obtained the potential for distributed photovoltaic development. The basic idea is: According to the national urban population and rural population announced by the National Bureau of Statistics in 2012, according to the per capita housing construction area of ​​the urban and rural population in the year, the total area of ​​the country's total roof area is considered. Considering that 20% of the roof area has the conditions for installing distributed photovoltaic facilities, The availability of the available roof area. According to the installed photovoltaic installation capacity of 150 watts per square meter, the total distributed photovoltaic installation capacity can be calculated, and then the full-load utilization hours can be calculated based on the solar irradiation intensity of each province (region, city), and finally the potential of distributed photovoltaics in each region can be obtained. Power generation.
Preliminary estimates indicate that the potential for distributed photovoltaic installation technology for residential roofs in China is 430 million kilowatts, and the potential generation capacity is 427.6 billion kilowatt-hours. Among them, the city's roof installation area is about 2.342 billion square meters, with an installed capacity of about 70.26 million kilowatts, and the potential for generating electricity is about 70.26 billion kilowatt-hours. The installed area of ​​rural roofs is about 11.910 billion square meters, and the installed capacity is about 357 million kilowatts. About 357.3 billion kWh.
Table 1 Estimated Development Potential of Urban Residential PV in China by Region
Table 2 Estimated Development Potential of Rural Residential PV in China by Region
Several important parameters or assumptions:
Per capita residential building area. This data is taken from the “Statistical Yearbook of China†of the National Bureau of Statistics. The latest data on urban per capita housing area and rural per capita housing area were in 2012. The average residential area per capita was 32.9 square meters in the country, and 37.1 square meters in rural areas. Each province (region, City) differences in specific values;
The total area of ​​residential roofs. It is not easy to obtain the area of ​​installable photovoltaic panels from the per capita residential area. Urban residents are mostly high-rise buildings, rural housing is more complex, and bungalows also have two or three stories of small buildings. This study simplifies the processing and considers that the average urban floor is 10 floors, which means that 10% of the total residential area of ​​urban residents is the roof area, assuming that 50% of the rural residential area is the roof area.
Can install photovoltaic panel area. Not all roofs are suitable for installation of photovoltaic panels, and the theoretical (or technical) area that is not suitable for installing photovoltaic panels must be removed. What proportion can be installed and the conditions of each building are different. According to the experience of some regions, we take 20% of this ratio, which means that 20% of the roof area can be installed with photovoltaic systems.
Installed capacity per unit area. According to the state of the art, the installed capacity of a crystalline silicon cell photovoltaic system can reach at least 150 watts per square meter, so that the total installed capacity can be calculated.
Full utilization hours. If there are actual projects, they can be based on the actual operation; if there are not many actual projects, they can be measured by radiation intensity. Knowing the radiation intensity in one place (kWh/m2) and multiplying the system efficiency (referring to the overall system efficiency behind the module, which takes 80% here), the full utilization hours are obtained, and the national average is about 1000 hours.
These are the key parameters for estimating the development potential of rooftop PV in China's distributed residential communities. Many of these are assumptions or empirical values, so there is a large or small difference from the actual situation. To develop distributed photovoltaics in the future, development potential is one of the keys to planning. Obviously, we still have a lot of work to do in this area.
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