Because different installation methods result in different costs and corresponding radiation levels, which in turn affect power generation and directly lead to different project benefits. Taking the tracking bracket as an example, single axis tracking is tracking the sun from east to west at fixed intervals and at a certain angle each time.
Tracking photovoltaic systems are generally equipped with motor drive devices, which can be powered from solar inverters or step-up transformers, as well as from external sources. The tracking system can maximize power generation while also reducing costs and increasing efficiency, truly achieving dual applications of agricultural photovoltaics. Existing dual axis tracking, independent single axis, linked single axis, etc. can significantly improve the terrain adaptability of the system and adapt to 0-15 ° slopes.
(1) Fixed type
When installing components, considering convenience and cost factors, fixed installation is currently the most mature, cost-effective, and widely used method. Due to the fact that on the winter solstice, the latitude in the northern hemisphere is subtracted from the Earth’s axis angle, and on the summer solstice, the latitude plus the Earth’s axis angle is added, the best way to fix solar photovoltaic arrays in the northern hemisphere is to face south and have an inclination angle close to the local latitude.
(2) Adjustable and fixed height angle
According to the seasonal differences in solar altitude angle, the tilt angle of the solar array is manually adjusted 2-6 times a year to increase the power generation of the solar photovoltaic array, with an average annual power generation increase of 4%.
(3) Single axis tracking
Distinguish whether a single axis is horizontal or oblique by the angle between its axis of rotation and the ground. The angle of the horizontal axis is 0, while the angle of the oblique axis is not 0. It can increase the power generation of solar photovoltaic arrays by more than 20%.
(4) Biaxial tracking
It can simultaneously track the azimuth and altitude of the sun, and the increase in electricity varies in different places: in cloudy and foggy areas, it can increase the annual power generation by 19% to 24%; In areas with more sunny days, the average annual power generation of solar photovoltaic arrays can be increased by 35% to 45%.
The following figure shows the annual peak sunshine hours at different latitudes, altitudes, and installation methods:
As shown in the above figure, compared with the fixed installation with the best inclination angle, the power generation of the solar photovoltaic array with flat single axis tracking increased by 16% to 29%, the power generation of the solar photovoltaic array with 5 ° oblique single axis tracking increased by 20% to 34%, and the power generation of the solar photovoltaic array with dual axis tracking increased by 35% to 43%. Among them, in low latitude areas (8 ° N and 24 ° 27 ′ N), the horizontal single axis has a better effect on increasing power generation, while in high latitude areas, the effect is relatively poor. The oblique single axis and double axis have a better effect on increasing power generation. Overall, when using tracking, there will be a significant increase in power generation.
In addition to considering power generation, other factors must also be considered, such as stability, price costs, maintenance costs, etc.
| Support form | Fixed type | Flat single axis | Oblique uniaxial | Biaxial |
| Technical maturity | Mature | General | In the demonstration stage | In the demonstration stage |
| Operating experience | Having experience in large-scale operations | Domestic operational experience | Domestic operational experience | Domestic small-scale operation experience |
| Operational reliability | High reliability | High maintenance costs | Higher | Low reliability |
Considering the actual situation of the project, in terms of cost, although single axis tracking is higher than the optimal fixed inclination angle, the additional electricity generated by the solar photovoltaic array is more objective. Therefore, this project has decided to adopt a flat single axis bracket installation method.