Cynthia Wang brings her own unique career experience to her role managing the supply chain for SB Energy’s pipeline of U.S. solar projects. SB Energy, which is part of the SoftBank Group, entered the U.S. market in 2019 when it acquired 1.7 gigawatts of existing projects, subsequently expanding its portfolio to over three gigawatts. As vice president of supply chain, Wang’s duties are expansive and include everything from sourcing equipment and EPCs for solar projects, to performing the due diligence necessary to ensure viable economics for each proposal.
In guiding critical choices about the equipment and companies SB Energy collaborates with, Wang keeps in mind an important lesson she has learned over the course of seven years in the solar industry: “I joke that people in the solar industry change jobs every two to three years,” she said. “It’s not because they want to change companies. It’s because the solar companies die.”
Such experience has taught Wang the importance of working with equipment suppliers that have extensive field experience and a solid financial foundation, making them reliable partners for decades to come. “The key for us is to make sure that equipment works for 35 years,” said Wang. “The number one priority for us is quality and reliability and a proven track record. The second priority is the ability to service the equipment for years to come, and that comes from being financially strong.”
This long-term view of working with reliable partners and suppliers helps explain why Wang defines levelized cost of energy (LCOE) using factors that are relevant over both the short and long view of a project’s life. According to Wang, there are three elements SB Energy looks to when assessing trackers: CAPEX (capital expenditures), OPEX (operating expenditures) and energy production. Wang noted that Nextracker provided the trackers in all 1.7 gigawatts of the projects SB Energy acquired when it entered the U.S. market. “We see LCOE evolving over the life of the project due to technology improvements, and we map it out over the 35 years of the project and create it as part of our financial model.”
The central role of trackers in LCOE
Wang and SB Energy are by no means alone in embracing a multi-pronged, long-term definition of LCOE. Rounak Kharait, who leads a team of 15 engineers performing solar energy assessments at the independent engineering company DNV and who previously worked at solar project developer NextEra Energy as a solar resource energy assessment supervisor, also says LCOE consists of CAPEX, OPEX and energy production. “We have to really focus on what makes sense for the lifecycle of the entire project rather than just optimizing for any one thing, like CAPEX.”
Like Wang, Kharait emphasized the importance of working with suppliers with a reliable and long-term track record. In fact, Kharait’s solar assessment team at DNV builds LCOE models that include assumptions about a tracker’s availability. “With a company like Nextracker which has had products in the field for years, we have confidence that the systems can have high level of availability, given that good operation and maintenance practices are in place” said Kharait. “When it’s a tracker manufacturer who doesn’t have the field data and the experience, then we adapt our modeling assumptions to alter the tracker availability.”
The three ingredients of LCOE
Perhaps the best way to analyze LCOE — and the best way to understand why Nextracker is so different from other tracker manufacturers — is to break it down into the three distinct elements Wang outlined: CAPEX, OPEX and energy production.
After 10 years specializing in single-axis trackers, Nick Price, the director of global sales engineering at Nextracker, has seen how the emphasis on CAPEX has changed as equipment prices have declined. “There has been a very intense focus on CAPEX over my entire career. That has been a key industry driver,” Price said. “But there is an increasing understanding about the other things that play into the overall cost of long-term ownership and LCOE.” Price pointed out that savvy EPCs and developers understand the relationship between CAPEX and energy production. Indeed, Price noted that a 1 percent energy gain over the lifetime of a project is approximately equivalent to a one-and-a-half cent reduction in total project CAPEX, depending on specific project conditions and financing details. It’s therefore critically important to consider tradeoffs that impact both CAPEX and energy yield in order to achieve a net LCOE improvement.
Nevertheless, it’s still important to think about how project CAPEX can be reduced. In part, that means looking at the installed cost of a tracker rather than just the price tag of the equipment itself. In that regard, Nextracker benefits from having installed over 50 gigawatts of trackers in every imaginable topography and environment across the globe.
That experience, along with long-standing partnerships with leading EPCs like Swinerton and Blattner, have yielded best practices that speed the installation process considerably. “There’s definitely a style of installation with Nextracker. Having the holes in the tracker torque tube align to the module rails, for instance, enables it to drop easily in place without any additional alignment,” said Price. “We are also unique in that we use two-piece or single-piece rivets, depending on the connection point. It’s the kind of thing where you set the fastener and the tool does the work for you. You don’t have to go back and do calibration or extra quality control checks afterwards. Those are the things that can slow installation time and increase project CAPEX.”
Wang offers a succinct way to think about the connection between reliability, quality and OPEX: “If a tracker is broken, it’s just like a fixed tilt installation,” she said.
In other words, the added production a tracker can provide is only possible when it performs as expected. “The industry standard is a warranty of five or 10 years. But what happens after that? Is the company going to be around to support you?” asked Price. “Everyone knows Nextracker is going to be around for the long term.”
Beyond company bankability, there are other ways Nextracker improves OPEX, including system granular visibility offered to customers with its NX Navigator Control System. The system allows for data to be gathered and analyzed from each tracker row, identifying potential problems. “Being connected to every single row means that you can do things like see that a motor is running at a higher amperage than a year ago. Since we’ve seen that profile in our fleet of 50 gigawatts, I know that means you need to replace the motor,” said Price. “Replacing it preemptively makes a big difference because it avoids the time needed to roll a truck to the site and having trackers down and losing production.”
Another differentiator with Nextracker is that there is unimpeded access down the entire length of each row because there are no drivelines in the way. This, along with the fact that adjacent rows can be oriented in the same direction to provide quick access to cleaning and maintenance teams makes vegetation management and cleaning fast and easy – and also allows for agrivoltaics, in which grazing animals handle vegetation management.
“If you have to work around or remove drivelines, it can almost double the amount of time spent mowing and cleaning,” said Price. “For a typical utility-scale power plant, the O&M budget for vegetation management and module cleaning dwarfs that of direct tracker maintenance. Enabling unimpeded north-south access of personnel and equipment is a primary driver in long-term O&M costs. It is important for solar plant developers and owners to factor in these costs when specifying equipment to deliver lowest solar levelized cost of energy.”
Years ago, the primary energy production versus cost tradeoff decision was whether it was worthwhile to use a more expensive tracker to produce additional energy or to rely on a cheaper fixed-tilt mounting system. With single-axis trackers delivering between 15 and 25 percent more energy today and only modestly increasing total power plant CAPEX, trackers clearly deliver superior LCOE for most of the ground-mount solar market. Trackers also enable significantly more energy to be harvested from the backside of solar panels than fixed systems, which has only been possible as the industry has scaled bifacial module technology over the last 5 years into production. Now, the technology decision question has shifted to comparing energy production between different tracker options.
In the early days of the solar industry, most utility-scale projects were built on flat tracts of desert land. As solar has become a mainstream energy source, projects today are constructed on a variety of landscapes across the globe, including hilly, rocky and oddly-shaped parcels of land. Nextracker’s terrain-following, independent row architecture enables more efficient use of available land, which translates to lower ground coverage ratio and more energy yield versus linked-row tracker designs. Among other challenges, this kind of terrain risks energy production losses due to shading. “The key to tracker design is to be able to eliminate shading,” said Price. “And the way to deal with that is to have independent rows that can react accordingly and avoid shading.”
One way Nextracker ensures projects avoid shading and maximizes energy production is with its TrueCapture technology. TrueCapture combines sensors, weather forecasting and machine learning to continuously adjust solar arrays to changing site conditions, which can result in energy gains of up to 6 percent. This can be particularly helpful to maintain production in projects installed a few years ago, staving off inefficiencies. “We are going back to sites that were built in 2015 and putting this product in and getting the sites producing more energy than when they were initially commissioned,” said Price.
Nextracker also helps projects fully leverage all potential production gains possible when using bifacial modules, with a bifacial optimized tracker design which boosts bifacial gain compared with other tracker options. For example, the backside of bifacial modules is exposed to more sun rays because they are elevated off tracker torque tubes and away from the drive system, letting in more light. Another way Nextracker boosts energy production is with a responsive stow system, which can allow a tracker to be operational soon after a wind event is over. “In the case of some other trackers, if there is a wind event in the morning, affected rows will be pushed into a stow position for the rest of the day,” said Price. “We employ real-time wind monitoring so that a tracker can be up and running 15 minutes after the wind has subsided. That makes a big difference with energy production.”
As the solar industry has matured, so too has its ability to more precisely quantify and evaluate the full lifetime value of projects. A long-term and holistic view of LCOE — one that acknowledges the unique role trackers play — is an important step in that direction.