Solar trackers have become important components of solar photovoltaic installations. Their ability to track the changing position of the sun in the sky can dramatically boost the energy gains of PV systems, by as much as 25 to 35 percent in some cases according to EnergySage.
Since debuting on the commercial market in the early 2010s, tracker technology has rapidly evolved to work across many different environments. Let's look at how the latest solar tracking solutions go beyond the limitations of previous models to deliver the best possible gains to solar projects.
Tracking progress: The benefits of flexibility of solar trackers
The first trackers required very flat and square-shaped tracts of land, which limited their overall utility. For example, they weren't optimized for terrains with significant undulations or irregular shapes, and couldn't accommodate nearby wetlands, drainage ponds, or pipelines, either. Placement on such nontraditional sites was often impractical and costly.
Fast-forward to 2018: It's now much easier to slot a tracking system into these terrains. Two major tracker design types have emerged in the U.S. solar industry to support today's projects:
● Central drive: The more traditional of the two options, it features one tracker in the middle of many rows of panels, and its motor drives operate simultaneously. Nclave, acquired by Trina Solar in 2018, offers a central drive tracker that can be up to 60 panels wide, with 18 rows for each motor to push.
● Distributed drive: Under this design, every row has its own motor and driver, and there's no interconnecting drive line like there is with central drive. These characteristics make it a better fit (than central) for the irregularities and obstacles we mentioned earlier, but there are distinctive pros and cons to each type.
Currently, Nclave offers a selection of both central and distributed drives. It takes a unique, pragmatic approach to each solar PV project, making technology recommendations that mix and match trackers as necessary. What should project managers know about their tracker options when working with Nclave and Trina?
Here's a look at some of the more technical details of the two major options, along with a popular alternative - the fixed tilt solar PV panel system - that can be implemented alongside them in a hybrid setup.
With central drive-based trackers, panels track east-to-west while the torque tube faces south. Compared to distributed drives, they have have sharper limitations on their flexibility and terrain type. For example, they can only handle 6 percent slope, whereas distributed tracking systems are compatible with up to 20 percent slope.
At the same time, central drives have key advantages elsewhere. First, they are generally easier to maintain than distributed ones, requiring fewer regular repairs and replacements. They are also better equipped for the heavy wind and snow loads that can easily damage and degrade the performance of distributed drives.
A tracker with a distributed drive is ideal for high slopes and variations in terrain. It's much more flexible than a central drive and there's even a self-powered option available from Nclave. This version doesn't require external power to its motors and accordingly has relatively low wiring costs. Since it's battery-powered, it's best suited to stable warm climates.
The flexibility of distributed drives is offset by a few technical limitations. It can't go as high in loading as a central drive. Plus, the higher number of moving parts means more frequent maintenance, even if the individual failures aren't as impactful as a central drive going down.
Fixed tilt solar system
Fixed tilt is a static framework, in which panels don't move. Instead, the modules are positioned toward a central point in the sky to boost annualized production from those panels.
Fixed tilt is much less expensive than a tracking system and might be the only feasible option for sites with numerous obstructions, rolling terrains or other complications. It doesn't deliver the same gains as a single-axis tracker, but it's often a practical alternative and may even be combined with tracking systems in a hybrid setup.
Which trackers should you choose for your projects?
Nclave and Trina Solar take a unique approach to solar PV projects, focusing on specific requirements and constraints and deploying a diverse set of solutions including central and distributed drives and fixed tilt systems. We can help you find the right technologies for your terrain.
Contributed by Trinasolar
With more than 20 years of experience in the solar industry, Trina has become a leader in commercial and utility-scale solar and is fully committed to all of its markets around the world, including the U.S.