Traditionally, solar trackers were ideally suited for flat lands. As finding and developing perfect flat lands for large utility-scale projects is getting more difficult due to cost, competing usage and resistance from locals, more and more projects are often associated with complex terrains. One route to handle a complex topography is to do the grading with earth work to realize a levelized surface. Alternatively, pier length can be increased to raise the tracker to maintain a uniform slope, which increases the amount of material used and costs in turn.
At the TaiyangNews Bifacial & Solar Tracker 2022 Conference, Lubaba Mawas Project Engineer at Nextracker spoke about solving developer challenges with bifacial-optimized and terrain-following trackers (see presentation here). Discussing the issues specific to grading, Mawas says that projects often face permitting and legislation clearance issues, which are more common in the western part of the world, as they require major earth work to prepare the site. And grading also increases EPC costs, typically by 15%, higher in high labor cost areas.
The ideal solution to this problem is to install terrain-following trackers, and Nextracker's NX Horizon- XTR does exactly that. The company achieves this by imposing a deflection in the tracker or the torque tube. This way, the tracker follows the terrain without having to grade or to increase the length of piers. This approach also brings in other advantages. Bypassing grading preserves the topsoil, thereby reducing erosion, which in turn reduces dust accumulation on the panels during the plant's operation. Mawas presented an estimation for a project in Portugal, in which NX Horizon-XTR showed the potential to reduce grading by as much as 65%. Savings of about $2.3 million were achieved in an already executed 250 MW project in the US, says Mawas.
Nextracker launched the NX Horizon-XTR at the end of Q1/2022 with 3 GW of trackers already installed and in operation, while it has 4.6 GW of installations under contract.
Clenergy's solution for such rolling terrain is its EzTracker. The tracker adopts a multi-point drive system with advanced electrical linkage technology. This enables the tracker array to be structurally divided into three small arrays according to the terrain, while sharing the same control system. Each small array is about 21 m long and has only three columns. This small array can flexibly adapt to various complex terrains. The modules are installed in double vertical rows. It can support up to 4 photovoltaic strings, with a total of 120 modules.
Next to adaption to rolling terrain, there have been several improvements for trackers recently (see Technology Trends In Solar Trackers). The majority of trackers companies are offering solar trackers that are compatible with bifacial technology and the role of trackers in agrivoltaics is becoming popular these days. Another interesting development is making use of artificial intelligence in controlling solar trackers, especially to calculate the optimal tilt angle for various weather conditions and terrains (see Intelligent Solar Trackers).
The text is an excerpt from TaiyangNews 2nd Market Survey on Solar Trackers, which was published in Dec. 2022 and can be downloaded for free here.