What are the common types of ground solar photovoltaic power station supports?

There are several common types of solar photovoltaic (PV) mounting structures, which are designed to support the installation and fixation of PV modules within a PV system. The choice of PV mounting structure can significantly impact the energy generation, land cost, and overall cost of a PV system, thus affecting its economic viability. This article provides a brief overview of common PV mounting forms, compares their characteristics, and also discusses some less commonly mentioned mounting structures.

1. Fixed Mounting Structure:

A fixed mounting structure is a PV support system with a fixed tilt angle. In ground-mounted PV projects, the optimal tilt angle for maximizing solar radiation throughout the year is usually determined using software like PVSyst. However, for projects with limited land availability, the tilt angle and row spacing may be optimized to achieve the best economic outcome.

In mountainous PV projects, where the terrain slopes are significant and module arrays may be more dispersed, fixed mounting structures offer advantages, such as a smaller footprint, lower labor requirements, and lower failure rates. Roof-mounted distributed PV systems, due to the challenges associated with maintenance and limited available space, typically employ fixed mounting structures or flat configurations.

2. Fixed Tilt-Adjustable Mounting Structure

Fixed tilt-adjustable mounting structures allow for a limited number of adjustments in tilt angle based on different times of the year to maximize solar radiation. Typically, these adjustments are made manually or with mechanical assistance. Fixed tilt-adjustable structures are generally adjusted twice a year, with one angle for summer and another for winter.

The specific adjustment months are determined based on the total radiation received on the tilted surface for each angle. PV systems using tilt-adjustable structures occupy approximately 1.1 to 1.3 times the land area of fixed structures and can increase energy production by around 5%, depending on site conditions.

3.Single-Axis Horizontal Tracking Structure:

Single-axis horizontal tracking structures can rotate around a horizontal axis, typically oriented north-south, to follow the sun’s daily movement. Common tracking angles range from ±60° to ±45°.

These systems occupy about 1.1 to 1.3 times the land area of fixed structures and can increase energy production by 8% to 15%, with a cost increase of 5% to 10%.

4.Single-Axis Inclined Tracking Structure

Single-axis inclined tracking structures allow PV modules to rotate around an inclined axis to track the sun and maximize energy production. These systems occupy about 2 to 4 times the land area of fixed structures and can increase energy production by 15% to 20%, with a cost increase of 10% to 15%.

5.Dual-Axis Tracking Structure

Dual-axis tracking structures can rotate in both east-west and north-south directions, enabling continuous tracking of the sun’s azimuth and elevation angles throughout the day.

These systems occupy about 2 to 4 times the land area of fixed structures and can increase energy production by 25% to 30%. However, they are more complex and have higher mechanical components, leading to potential stability issues.

6.Flexible Mounting Structure

Flexible PV mounting structures consist of a large-span support structure with pre-stressed flexible cables connecting the two ends. The cable span typically ranges from 20 meters to 40 meters and can be even larger. PV modules are installed at a low tilt angle, typically around 10° to 15°. Flexible structures are suitable for steep terrains with slopes greater than 35°, areas with high clearance requirements (such as fishery and agriculture integration projects), and distributed PV systems where space is limited.

These structures are particularly well-suited for challenging environments and situations where traditional mounting may not be feasible. Current commercial projects in China typically have capacities in the low megawatt range.

In addition to the above common PV mounting structures, less common variants such as Azimuthal Single-Axis Tracking Structure and Horizontal-Inclined Single-Axis Structure are briefly discussed.

7.Azimuthal Single-Axis Tracking Structure

Azimuthal single-axis tracking structures mount modules at a specific angle and rotate around a vertical axis, tracking the sun’s azimuth angle rather than its elevation angle.

8.Horizontal-Inclined Single-Axis Tracking Structure

Horizontal-inclined single-axis tracking structures install modules at a fixed southward tilt angle and rotate around a horizontal axis aligned with the north-south direction, similar to a single-axis horizontal tracking system.

The choice of PV mounting structure depends on various factors, including the local solar radiation conditions, land availability, and economic considerations. Currently, in China, large utility-scale projects typically use fixed mounting structures, while other types of structures are less commonly employed for various reasons.

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