I. Factors affecting the occupation of photovoltaic projects
First of all, it must be confirmed that the installation method of the photovoltaic project, fixed type, flat single axis, oblique single axis, double axis, different installation methods, the floor space difference is very large.
Secondly, it must be made clear that the PV footprint consists of two parts: “photovoltaic square field” and “substation”.
The footprint of the "substation" is affected by the voltage level, 10kV, 35kV/66kV, 110kV, 220kV, 330kV. Different voltage levels, the area occupied by the substation is definitely different. The table below shows an approximate value for the substation footprint for different voltage levels.
Taking the fixed installation method as an example, the floor space of the “photovoltaic square field area” is affected by four factors, as shown in the following figure.
1. The floor space of “photovoltaic square field area” is affected by “site conditions”
If it is a distributed "concrete roof" and "color steel tile roof", the difference in footprint is very large. In general, the same installation volume of the floor space, "concrete roof" > "color steel tile roof."
If it is a ground power station, the land is divided into flat land, with a southward slope and a northward slope. The floor space will vary greatly. When other conditions are the same, the area of the same installation amount has a north slope > flat land > a south slope.
We cannot explain all the situations one by one. The following can only continue with the description of “flat land”.
2. The floor space of “photovoltaic square field area” is affected by “transformation efficiency of photovoltaic modules”
“Photovoltaic module conversion efficiency” increased by 1%, and the “photovoltaic array field” area will be reduced by about 5~9%.
3. The footprint of the “photovoltaic array field” is affected by the “photovoltaic array tilt angle”
When the other conditions are the same, the "photovoltaic array tilt angle" is reduced by 1 °, and the "photovoltaic square field area" is reduced by about 0.5 to 2%.
4. The floor space of “photovoltaic square field area” is affected by “latitude”
The main effect of "latitude" is "shadow magnification". "Shadow magnification" is the ratio of the length of the shadow formed by the obstruction to its height. Generally, at the time of design, the shadow magnification at 9:00 and 15:00 in the true winter sun of the winter solstice is mainly considered.
In the northern high latitudes of Heilongjiang, Xinjiang, Inner Mongolia and other provinces, the latitude is above 40°, and the shadow magnification is >3. In Guangdong, Guangxi and other latitudes below 25°, the shadow magnification is about 1.5. Therefore, in the northern region, the front and rear array spacing will reach more than 6m; and in some parts of the south, the maintenance channel with 2m spacing between the front and rear arrays is sufficient.
Therefore, the “latitude” is increased by 5°, and the “photovoltaic field area” will increase by about 10% to 30%.
Second, the estimate of the floor space
On December 2, 2015, the Ministry of Land and Resources issued a notice on the “Control Index for Land Use of Photovoltaic Power Station Projects” (Guo Tu Zi [2015] No. 11), and the annex covers the land area under various conditions.
The first step is to determine how the PV array is installed.
Fixed, flat single axis, oblique single axis, dual axis tracking, to choose a different table;
The second step is to determine the conversion efficiency of the PV module.
The third step is to determine the terrain condition coefficient.
By multiplying the value obtained by the query by the corresponding terrain condition coefficient, the floor space of an item can be estimated.
The table below shows the footprint of different installation modes and different conversion efficiencies below the horizontal plane.
Use suggestions:
1. The reference area in the table is the area of the PV array area, excluding the booster station and living area.
2. Estimation under different terrains
Table 1: Reference for the construction of the best inclined angle fixed 10,000 kW photovoltaic array (unit: hectare)
Table 2: Reference for the construction of the optimal tilt angle fixed type 10,000 kW photovoltaic array (unit: mu)
Table 3: Reference for flat single-axis tracking of 10,000 kW PV array construction site (unit: hectare)
Table 4: Reference to the construction site of flat single axis tracking 10,000 kW photovoltaic array (unit: mu)
Table 5: Reference of the optimal tilt angle oblique single-axis tracking 10,000 kW photovoltaic square array construction site (unit: hectare)
Table 6: Reference of the best tilt angle oblique single-axis tracking 10,000 kW photovoltaic square array construction site (unit: mu)
Table 7: Reference for construction of two-axis tracking 10,000 kW PV array (unit: hectare)
Table: 8: Reference for construction of two-axis tracking 10,000 kW photovoltaic array (unit: mu)
