Repowering trackers can extend profitability of solar arrays entering their golden years

In the 2010s, there was still some discussion about whether single-axis trackers for solar arrays were worth the added expense of installation, operation and maintenance for the increased electricity production they promised. That question has been settled in the affirmative, at least at the utility scale.

“I started my first tracker company in 2008, and at that time we expected that trackers eventually would penetrate about 70% of the utility market,” Matt Schneider, founder and principle at consultancy Solar Perspectives, told pv magazine USA. “I think they’re closer to 90% now. And as you and I both know, no one does anything in this industry for any reason other than financial.”

Schneider says trackers essentially produce a return on investment after about four years. Since the lifespan on a commercial array may reach 30 years, presumably following the sun has been a major factor in the financial success of solar power, at least at the utility scale. On the other hand, the oldest projects are reaching their golden years, which do not necessarily translate into profitable operations.

The overall success and durability of the solar industry is bringing the notion of “repowering” to the forefront. According to a recent white paper from Arizona-based motion-control systems manufacturer Kinematics, the global solar tracker market reached 444 GW of installed capacity in 2024. At some point during the operation of this capacity owners will be faced with the prospect of replacing or upgrading project components during the course of its service life.

While the cost of replacing or converting aging or damaged solar modules, not to mention inverters, were likely calculated during project development, tracker replacement may have been something of an afterthought. Magnus Asbo, chief product strategy officer at Kinematics, told pv magazine USA that ideally this is as it should be.

“Essentially, the mechanics of trackers are exceptionally reliable, and as a manufacturer we are very proud of how long they last,” Asbo said. “They should last for decades upon decades of good operation. However, what we have found is that not all components are created equal. And in an industry where there’s a lot of cost pressure, people have selected equipment that does not always have the kind of lifespan that that they might have hoped for.”

Asbo points out that the “somewhat arcane” structure of ownership for utility-scale solar projects can also serve to divert attention from the need to repower systems. The component manufacturer sells to the tracker manufacturer, which sells to the engineering, construction and procurement (EPC) form, which sells to the developer, which sells the project to an independent power producer (IPP).

“The decision of tracking versus not tracking is pretty much a financial one, and generally it has been an exceedingly good decision invest in trackers,” he said. “The thing that’s interesting is about repowering is that at this point the group having the greatest interest in the functionality of the tracker is no longer the EPC; it is the IPP. Oftentimes, as a financial investor, the IPP is less focused on the technology of PV and more interested in managing the finances.”

According to Asbo, like it or not, dealing with loss of power production due to tracker difficulties is something a utility-scale solar asset manager is likely to face at some point. If a production shortfall is serious enough, the IPP might be liable for the cost of procuring energy from an alternate supplier or even the possible cancellation of a power purchase agreement.

Fortunately, good arguments can be made to finance-focused owners that repowering trackers at the component level is vastly preferable to removing, replacing and remounting entire assemblies.

“What we’re finding is that the decision to repower a system that is no longer tracking will pay off sometimes well within a single year,” he said.

Trackers themselves can be imbued with intelligence that can prolong the life of the array. In an August webinar, engineers from consulting firm VDE Americas and tracker manufacturer Game Change Solar presented how an automated stow mode for trackers can help protect an array during hail and high-wind events by angling modules to minimize damage from impacts and sustained winds. The HailStow system is available for its Genius Tracker.

Scott van Pelt, chief engineer at Game Change, said the company is using weather forecasts to look at real time conditions compared with triggers based on historical wind and hail events. If conditions warrant, the system can automatically enter stow mode or an alert is sent to operators who may then send a stow command manually. Similarly, a restore command can be sent automatically or manually when the store trigger conditions no longer apply.

“It may only be a couple of minutes, but all trackers take a little bit of time to move from whatever orientation they happen to be at to that steep stow angle where they’re most robust or least likely to take damage from hail,” van Pelt said. “But any event, it’s very important that trackers be designed to have the capacity for wind loads coming from either the front or the back of the module.”

Game Change worked with VDE Americas to implement the models used to create the trigger conditions for its HailStow system and to validate its performance in the field. The HailStow technology can be retrofitted to existing Genius Tracker installations to help prolong their operational life.

Solar Perspectives’ Schneider, who serves as a technical advisor for Kinematics, said there are about 380 GW of tracking solar in the United States, which amounts to about nine million units in the field. As he puts it, not every vendor has achieved Toyota RAV4 levels of component quality. Moreover, some vendors have gone out of business. Repowering arrays with new components and technology, he says, can be a cost-effective way for IPPs to overcome the effects of time and market reversals on their productive assets.

“If a tracker pays for itself in four years and it’s lasted that long, you’re already ahead on money than if you had gone with fixed racking,” Schneider said. “You’ve already paid for the tracker and gotten twice its value back at year 10. And now the question is, do I want to do that for the next 10 or next 20? And the answer is likely ‘yes,’ right?”

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