While not groundbreaking, there are also some interesting developments in the trackers segment that are worth taking note of. Talking about solar tracker stability versus mainly wind loads, Emmanuele Chiappori, Global Engineering Director Antaisolar, stressed at the TaiyangNews Tracker event that design codes are not adequate enough for making a reliable tracker product (access the Antaisolar presentation here). He emphasized the need to conduct wind tunnel tests (WTT) to correctly capture static loads, dynamic loads and instabilities.

Chiappori presented the key results on each of the aspects in WTT. The tests found that the static loads vary depending on the tracker position in the layout of the solar plant. Damping ratio is a key characteristic of the tracker that defines its response to dynamic wind loads. As for tracker instabilities, flutter, torsional divergence or galloping, vortex lock-in and wake buffeting or resonant vibration are the important ones. Chiappori also provided a summary of different approaches to capture these instabilities. Increasing stiffness of the tracker is the most significant intervention to increase a tracker’s stability, which can be done by increasing the size of the torque tube or it can also be achieved by shortening the free span length. Putting this into perspective, Chiappori emphasized that Antaisolar’s products are adapted to larger modules with up to 7 strings. As a result, the trackers can measure up to 240 m in length. Still, the products are stable as they are based on a multipoint design-based driving system. Going into the details, fixing points along the tracker length help increase the tracker stiffness, decreasing the free-span length (see Long Antai Tracker For Large Modules).

Tracker manufacturers offer different module mounting options: 1P, 2P, 2H, 3H and 4H. However, the mainstream configurations are 1P and 2P, and several companies are offering both the platforms. While 2P used to be more popular, it has been losing ground. More and more companies are launching new products based on the 1P platform, a trend also emphasized by TrinaTracker (see A “SuperTrack’er). This is further confirmed by latest product launches from FTC, Ideematec and Soltec that are 1P trackers. According to Antai, it is also important to define if it is a single or multipoint tracker. 1P single fixed point is the simplest solution that is highly accepted in Europe. The multipoint solution offers potential cost reduction because of the low defense angle. The drawback of 2H or 4H is that they are not adapted to bifacial modules. Antai further emphasizes that the 2P solution is more prone to instability but a well-designed 2P tracker can be as stable as a 1V tracker. Schletter says it can cover all mounting possibilities, but 1P is its favorite.

One of the major developments in the entire PV segment is the larger module form factor. The increasing size and weight of these modules have been a challenge for tracker manufacturers to keep track. Leading tracker suppliers have optimized the stability of their products to accommodate larger modules. Tracker makers are also increasingly focusing on designs that can sustain higher wind loads. Antai says that 3-string trackers with a single fixed point have been the typical solution employed so far. For a 1V configuration, it means that the trackers stretch up to 90-95 m, which is still acceptable. With bigger panels, tracker lengths could increase up to 110-120 m, which is a bit too much, according to the company. For this reason, with a single fixed point, 2 strings is the only available solution, but with multipoint trackers more strings can be put together in the same tracker, emphasizes Antai.

Agrovoltaics is a very small but very promising application arm of PV, where power generation can go hand in hand with farming, and trackers find good applicability here. The first tracker companies are working on solutions focused on agrovoltaics. The use of trackers not only improves yields, but it can also help in shave noon peaks. In this so-called Anti-Tracking approach, solar panels are turned away from the sun in a closed-loop control manner. It smartly avoids the energy dissipation but restricts production (see Overview Of Solar Trackers).

It is no surprise that tracker manufacturers are trying to save on steel, the price of which has increased considerably in recent times. Trackers built with less steel while maintaining reliability have hit the market. Low carbon footprint is also a topic of interest for PV installers, in particular in Europe, and manufacturers are working in this direction as well.

Some companies are also setting up local procurement channels to reduce logistics costs and shorten delivery times.

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.