The assembly of structures and solar trackers is the phase that turns prepared ground into a plant capable of generating power. It is not an isolated mechanical task: it depends directly on the prior pile driving work and it shapes everything that follows.
Before getting into the sequence, it helps to place this phase within the broader photovoltaic plant installation. Structure assembly begins right after the foundation work ends and continues until the electrical installer can start wiring the modules.
What structure and tracker assembly includes on a solar site
The scope of this phase goes beyond placing the structure. It includes the complete mechanical assembly, the alignment of every row and checking that each element meets project tolerance before a single panel is installed.
The tasks that make up structure and tracker assembly are:
- Assembly of the torque tube or the fixed structure profile onto the already-driven posts
- Installation of bearings and motors for single-axis trackers
- Alignment and levelling of every row according to the executive project
- Fitting the clamps that will hold the modules
- Connection and calibration of the tracker control system, where the design includes one
A misaligned structure is not caught until the electrical installer tries to fit the modules, and by then correcting it costs several times more than getting it right the first time.
Site sequence: from setting-out to fitting the modules
The order of tasks is not interchangeable. Each step depends on the previous one, and a setting-out error carries through the entire assembly phase.
Setting-out and foundation verification
Before any assembly starts, the driven posts are checked against the project’s verticality and alignment tolerance. A deviation of just a few degrees in the piling multiplies once it reaches a full structure row.
Structure assembly: fixed or tracking
With fixed structures, the support profile is assembled directly onto the posts. With trackers, the process adds the assembly of the torque tube, bearings and motor, plus calibration of the east-west tracking angle.
Fitting modules and mechanical connection
Once the structure is levelled, the clamps that will hold the panels are fitted, with a final torque check on every anchor point before handing over to the electromechanical assembly team.
Fixed structure or solar tracker: what determines the choice
The choice between fixed or tracking structures for solar panels does not depend on budget alone. The geotechnical study, the terrain profile and the developer’s production target matter just as much.
On uneven terrain, a fixed structure remains the most robust and economical option to assemble. On large-scale plants with homogeneous terrain, a tracker usually justifies its extra cost through the production gain.
Who carries out the assembly: manufacturer, EPC or civil works contractor
Structure assembly is usually carried out by the same team that did the pile driving, not by the structure manufacturer. The manufacturer supplies the kit and, on some projects, oversees the first row as quality control, but the field assembly belongs to the civil works contractor.
This phase is part of the wider process of building a photovoltaic solar farm, sitting between the foundation work and the final electromechanical assembly.
Splitting the piling team from the structure assembly team multiplies dead time between phases and is one of the most common causes of delay on large-scale plants.
Own machinery and coordination with piling: the timeline factor
Structure assembly moves at the pace of the piling work ahead of it. When both teams belong to the same company, coordination between phases cuts the dead time between driving a row of posts and starting its assembly.
At Site & Field Global Solutions we carry out piling and structure assembly with our own machinery and crews, which removes the dependency on third-party subcontractor availability during peak sector demand.
According to the Spanish Photovoltaic Union on ground-mounted plants, Spain holds a strong industrial position in structures and solar trackers, with world-leading companies in this part of the value chain.
The civil works for photovoltaic plants includes structure assembly as one of its critical phases, sitting between the foundation work and the perimeter fencing.
Common mistakes in structure and tracker assembly
Cost overruns in this phase almost always share the same root cause: poor coordination between teams or insufficient precision in the prior setting-out.
- Not checking the piling tolerance before starting structure assembly
- Subcontracting assembly to a different team than the one that did the piling, without a handover protocol
- Skipping backtracking calibration on trackers, which creates shading between rows
- Failing to record anchor torque values, which complicates later maintenance
The market for single-axis solar tracker manufacturers has consolidated in Spain around simpler, more affordable solutions than the older dual-axis trackers, precisely because of their lower assembly and maintenance complexity.
Having reliable information on what photovoltaic energy is and how each technology behaves helps developers decide on technical grounds, not just cost.
Well-executed structure and tracker assembly goes unnoticed in the day-to-day running of a plant, but poor assembly is noticed, through breakdowns and lost production throughout the plant’s operating life.
Frequently Asked Questions about Solar Structure Assembly
What does structure assembly include on a photovoltaic site?
It includes assembling the profile or torque tube onto the driven posts, installing bearings and motors for trackers, aligning and levelling every row, and fitting the clamps that will hold the solar modules before electromechanical assembly.
What is the difference between a fixed structure and a solar tracker on site?
A fixed structure is assembled directly onto the posts at a constant angle. A solar tracker adds bearings, a motor and a control system to orient the panels toward the sun, which demands greater assembly precision and more maintenance afterward.
Who assembles solar trackers: the manufacturer or the civil works contractor?
Field assembly is usually carried out by the civil works contractor, who also did the pile driving. The manufacturer supplies the assembly kit and, on some projects, oversees the first row as quality control.
What machinery is needed to drive posts and assemble structures?
An approved pile driver is needed for the foundation work, along with lifting and torquing equipment for structure assembly. Having own machinery for both phases removes the dependency on outside subcontractor availability.
How is structure assembly coordinated with pile driving?
Assembly moves row by row behind the piling team, first checking the verticality tolerance of each post. When both teams belong to the same company, dead time between piling and structure assembly is reduced.
If your project is at the civil works stage and you need a contractor with its own machinery for piling and structure assembly, contact our technical department.
