SPICon 2019 Recap: NX Rockstars Uplevel Future PV Power Plant, Bifacial and Quality Conference Discussions

By on October 2, 2019

Few industry tradeshows carry as much weight on the NEXTracker calendar as Solar Power International, the flagship event of the U.S. solar and storage industry and beyond. This year’s edition of SPI (now part of North American Smart Energy Week) in Salt Lake City took on even more gravitas, as it provided the launchpad of the latest addition to the NEXTracker product family: the NX GeminiTM two-in-portrait single-axis solar tracker for challenging terrain and ultra-high wind conditions, delivering the industry’s lowest number of foundations per megawatt.

Engineered for resilience, NX Gemini’s innovative 2P architecture results in shorter overall row lengths for design flexibility and contiguous solar panels for maximum array density.

But the show also provided an opportunity for some of our NX Rockstars to uplevel the technology and market discussions at various conference sessions.  

When it comes to going deep on solar and clean energy technology, NEXTracker CTO Alex Au can rock the house. He participated in two sessions during SPI, sharing a vision of utility photovoltaic (PV) power plants of the future that incorporate a “tremendous opportunity” for optimizing systems and hardware.

At the heart of Alex’s big idea is the use of fixed-voltage DC bus technology, which could be standardized across the PV, inverter and storage assets and provide much higher DC:AC ratio capture of “clipped” energy. The use of fixed DC bus enables asset owners to add PV or storage at any time with any vendor, offers more choice of inverter without being limited by maximum power point tracking (MPPT) configurations, and would accelerate storage adoption by generally targeting DC outputs that can be met by inverter suppliers, he explained. Inverters could see their nameplate rating increase by up to 30%, he estimates, since MPPT would no longer be needed and could operate at the top end of their voltage range—at no additional cost.

On the PV side, intelligent solar trackers equipped with bifacial modules and smart control systems like TrueCaptureTM would provide increased energy harvest.

This chart above shows how software optimization like TrueCapture and advanced digital O&M services can boost production based on a theoretical optimum model. With the right approach incorporating the NX ecosystem and controls, we can bring additional value to our customers.

Greg Beardsworth, director of product management and maven of our crack bifacial team, joined Leidos’ Anastasiia Watters to talk about bifacial energy performance and present a short case study on the initial results from the NEXTracker’s bifacial testing arrays at the Center for Solar Excellence in Fremont, CA. As Greg noted, the company’s bifacial business is taking off, with more than 1.8 GW either deployed or contracted. The additive bonus of pairing bifacial with TrueCapture appeals to many customers in search of maximizing their energy yields.

The initial data from the center supports the early adopter developers’ bullishness on the technology. The center uses different modules and varying albedo conditions, the best of which are showing daily bifacial and energy gains exceeding 10%, with modeled versus measured performance on the test trackers seeing prediction accuracies within 0.5%. Although the work to date has been done on the bifacially-optimized NX Horizon tracker, Greg noted that bifacial modeling for NX Gemini has begun. He stressed that both platforms will have excellent bifacial performance, and that site conditions will play a bigger role than bifaciality in determining the right tracker for a particular project.   

If anyone has earned rockstar status in his field, it’s Kent Whitfield, NEXTracker’s VP of quality, who took part in PV magazine’s Quality Roundtable at SPI. Although his presentation was initially titled “Best Practices to Ensure Maximum Tracker Uptime,” Kent’s focus on the need to minimize process variability and enhance quality and process control in manufacturing went well upstream to make the connection to optimized field performance. He pointed out that while the QC techniques used to date have served us fairly well, it’s time to embrace statistical quality control (SQC) and its big sibling, statistical process control (SPC), to meet the demands of high-volume manufacturing in this multi gigawatt age.

Kent noted that NEXTracker ships an average of 115 MW of material per week, which includes in the neighborhood of 50,000 piers, slews and torque tubes and 370,000 modules, rails and fasteners. Even with the company’s very high level of quality and process capability (Cpk) metrics, the sheer volume involved means a small quantity of defective or out-of-spec parts will slip through. To drive that defect count even lower—especially as we see production volumes skyrocket to meet the projected growth over the next decade—a collaborative effort will be required to bolster quality and process control up and down the value chain, from the component supplier community and original equipment manufacturers alike. 

What kind of volumes are we talking about? Using SEIA’s new Solar+ Decade roadmap as a yardstick, the radical market transformation needed to achieve at least 20% solar+storage of U.S. electricity generation by 2030 will require 500 GW of solar to be installed, most of that at utility-scale. And that’s just in the U.S.

What does this mean? Companies like NEXTracker will have to significantly increase production output to meet deployment demands while continuously moving the needle on quality and process control. Technologies like integrated bifacial PV tracker systems and smart, connected solar-plus power plants will help us achieve those goals, but quality and reliability must be a cornerstone of their execution.