In many ways, the future of the solar industry is on full display in Lamar County, Mississippi. It's in this largely rural area west of Hattiesburg that the 52-megawatt (AC) MS Solar 3 project was constructed and began producing enough clean energy to power over 11,000 homes in 2017.
Developed and constructed by Miami-based Origis Energy — which has developed over 100 projects totaling more than 1-gigawatt worldwide — MS Solar 3 is a reflection of the dramatic and rapid evolution of solar around the world. Gone are the days when large, utility-scale projects only made economic sense in states where electricity prices were high, state incentives generous, and flat desert land abundant (think California and Australia).
Price declines and significant improvements in technology have combined with increased financing sophistication to make large solar projects economically attractive in states like Mississippi, where sites are typically rolling and subject to shading issues. An important tool Origis had to navigate the challenges in Lamar County was to deploy NEXTracker's TrueCapture™ software, which can help project developers and owners operate their power plants in a way that maximizes production in hilly terrain and diffuse conditions.
"When you have complicated sites with variable terrain or structures which cause row-to-row seasonally variable structural shading, it is critical to have a system which is intelligent enough to optimize the plant on not just an individual tracker basis but which also contemplates the impacts from row-to-row across multiple trackers," said Michael Eyman, Managing Director for Origis Services, an Austin, Texas-based wholly owned subsidiary of Origis Energy that provides operations and maintenance (O&M) and asset management services to a project portfolio of over 500 megawatts. Eyman credits TrueCapture (more about how it works in a moment) and NEXTracker's staff for improving electricity production and financial performance for the owners of MS Solar 3.
Importantly, there are also project financing benefits when the production boost made possible by TrueCapture are verified by an independent engineering (IE) firm. In the case of MS Solar 3, the financing was set up with a standard partnership flip structure with Origis Energy sponsor equity construction funding the pre-commercial operation followed by a capital stack of sponsor equity, tax equity, and long-term debt. A first step in the financing process was an IE vetting how the project's production would be impacted with the use of TrueCapture. "That was indeed a prerequisite from day one for an IE on MS 3 and that happened. It is also our approach with our financing partners going forward for any new project where we would consider NEXTracker with TrueCapture," aid Johan Vanhee, Chief Commercial Officer & Chief Procurement Officer with Origis Energy. According to Vanhee, there are solid reasons to include TrueCapture in the future. "The effect is that TrueCapture provides for a genuine uplift on the energy yield of a project, which obviously affects the financing of the projects in a positive way," he said.
How TrueCapture works
TrueCapture is the culmination of a years-long research and development project by NEXTracker, which is based in Fremont, California, and is the world's largest manufacturer of solar tracker systems. The research was aimed at optimizing the way trackers function in order to maximize energy production in the kinds of geographies where more and more projects are being proposed.
"The first objective was the elimination of inter-row shading that occurs at the bottom inch or more of modules, which is a result of undulating topography, or construction variance," said Luke Wyant, NEXTracker's TrueCapture Business Development Director.
Obviously, no two sites are exactly the same, which is why NEXTracker assesses the actual tracker row height once construction is completed and feeds that information into how TrueCapture positions modules. Continuous monitoring of the operation of each row ensures optimal generation. "We remotely observe tracker angles every minute of every production hour through the year and are able to confirm the optimal angle to avoid shade from one row to the next," Wyant said. "To execute this optimization, we run the actual tracker row heights through a ray trace model and identify how to best control each row."
TrueCapture was also designed to maximize energy production under diffuse conditions. It accomplishes that through a combination of sensors and predictive technology that detects irradiance patterns at each project location. This information allows TrueCapture to adjust the position of the modules to adapt to changing weather. "Before this, everyone assumed it was best to point the modules at the position of the sun," Wyant said. "But when clouds are overhead, photons scatter to the ground instead of taking a direct path to the solar array. When that happens, it's best for the modules to go into a flat position to optimize production from cloudy conditions."
The boost in performance is significant. On cloudy days, TrueCapture has been demonstrated to increase energy production as much as 35%. The combined benefits of TrueCapture improve energy production up to 6% annually.
By addressing the effect of row-to-row shading as well as diffuse conditions, TrueCapture is responding to the evolution of the utility-scale solar market in the United States and internationally. Indeed, in places like Texas, Australia, and certain markets in Latin America, developers are constructing such large solar plants that even a fraction of a percent increase in production over the 25 to 35 years of a project can boost the amount of revenue earned by millions of dollars. "In the eastern U.S., there are a lot more land constraints, and a 100-megawatt project is more likely to be parsed out to numerous project blocks due to hills and ravines rather than in one square rectangle in the desert," Wyant said. "Boosting performance by using TrueCapture is a way to make more and more projects in some of these newer geographies financially viable."
Validated software equals investor confidence
Software is playing an increasingly important role in financing these projects. In large part, that is because TrueCapture is the first product of its type being validated by IEs that banks and other financial institutions rely on to inform their investment decisions.
"My personal mission, and the mission of our group, is to support the development of reliable, high quality solar projects and to make sure they perform as expected over their lifetime," said Anat Razon, Head of Section, Solar Due Diligence for the independent engineering firm DNV GL. "Our role, in terms of supporting financing, is to identify and mitigate risks and raise any red flags we see in order to increase the certainty for investors. This is particularly important when you look at the smaller margins and lower PPA [power purchase agreement] prices in the industry today."
Razon said a significant gap in performing the work necessary to give investors the confidence they need to back projects has been the ability to assess losses due to uneven terrain quickly and consistently, but now DNV GL has built internal tools that allow accurate modeling of these scenarios. DNV GL can validate the energy-production increase that TrueCapture has the potential to deliver. "It's important to understand the technology and to be able to model those benefits correctly. I would encourage all financial institutions to ask IEs for their energy validation studies to confirm that the energy assessments are trueing up to actual system performance."
In addition, financial institutions should scrutinize current assessments to make sure losses from uneven terrain are incorporated. Then a detailed analysis of TrueCapture can be performed to understand the potential performance increases," she said. "As more solar is being deployed, there has been a need to automate and digitize our knowledge base. We can't keep up without software, and I'm excited to use these tools (including DNV GL's SolarFarmer product) to bridge the gaps we have seen with bifacial modules and energy optimizing tracking algorithms."
