Hanson Wood still remembers how bewildered colleagues were when he developed his first rooftop solar project for EDF Renewables (EDFR) in 2007. At the time, EDFR was developing 100 and 200-megawatt wind projects. “People would ask me, ‘what’s the big deal about this 150-kilowatt rooftop solar project?’” recalls Wood, who has been with EDFR for 15 years and today leads the company’s development of solar, wind and storage projects across the western United States. “I said it was all about the promise of what was to come. And now, solar is largely the future of energy.”
In many ways, the progression of solar from interesting novelty to the point where it accounts for most new electricity generating capacity in the U.S. has been straightforward. Aided by a mixture of manufacturing scale, improved economics, and technology innovation, solar has become a mainstream energy source over the past decade by following a fairly simple construction recipe: Build on flat swaths of land in states with generous amounts of sun and abundant financial incentives.
The number of decisions about modules, trackers, insurance, and design that developers and their partners had to get right in order to execute a successful solar project was mercifully low. That is no longer the case today. “If you design it correctly, solar can compete against conventional energy in so many different markets,” says Wood. “But given the volume of projects and variety of local conditions, there is a significant challenge to design every project optimally and price it competitively. What makes it so complex is there are many different factors that need to be weighed and balanced – what we’ve learned is there is no one path to optimization for all projects.”
From a few decisions to many
Let’s unpack why finding the best solution for any solar project has never been more difficult – and why successful projects today require making dozens of nuanced and complicated decisions. For example, the selection of modules was once limited to similar sized thin-film or silicon panels. Today, module choices have expanded to include bifacial and, increasingly, large format panels.
Consider how module choice has ripple effects on the optimal design of solar projects, especially those being built in newer markets like Texas and states in the Midwest and Southeast. Besides having hilly and rocky terrain that pose unique design challenges, projects in these markets also have to consider weather, particularly high winds, hail, and floods.
“Bifacial modules perform well, but the glass is thinner. It’s two millimeters on the front and two millimeters on the back, whereas it used to be 3.2 millimeters just on the front,” says Melissa Cooke, manager of project engineering at Nextracker. “Bifacial actually performs better structurally in higher winds but is worse for hail. Then again, larger format modules mounted on trackers require more steel and longer trackers. If you look at just one scenario, it is very easy to solve. But every single month the industry gets more complex and you add new layers that make it more difficult to solve for.”
Indeed, module selection is just one of many choices that need to be made. In certain markets, like Mexico and Chile, low upfront costs drive project design decisions. But in the U.S. it’s important to limit capital expenditures (CAPEX) with the long-term objective of lowering operating expenses (OPEX) and ensure maximum production over the project’s lifetime. “EPCs are experts on such things like cost to build and construction feasibility,” says Cooke. “The owner is an expert on such things like insurance, overall performance, and O&M.”
A premium on partnership
The sheer number of nuances and complexities involved with building and operating a successful solar project is difficult to comprehensively chronicle. Besides the need to address harsh winds and hail into the designs of projects, there are also supply chain challenges – which have been highlighted during COVID-19 – that must be solved early in a project’s development.
“Months before construction starts on a solar project, the material needed to build a project is procured, rolled out and galvanized to specifications,” says Jason Oberg, manager of engineering at Blattner Energy, a leading EPC focused on utility-scale solar, wind, and energy storage projects across the U.S. “This is done to ensure we meet delivery schedules.”
Not only has the number and complexity of decisions multiplied, the amount of time to make the right decisions is short. “We work on behalf of our customers, the project owners, to build safe and quality projects that are on schedule. Schedules vary from project to project but they all typically have tight timelines,” says Oberg. “A key to overcoming complexities and still delivering safe, quality projects on-time is collaboration with customers and partners.”
A growing trend within the industry for owners, EPCs, module makers, and tracking manufacturers is to work together closer than ever before. For example, Blattner worked with Nextracker on a project called Maverick to reduce installation time. The two companies teamed up to discuss different ways to incorporate newer technologies without impacting the overall construction schedule. By focusing on packaging, logistics, shipping and staging the site, the companies developed an innovative solution that provided short and long-term cost benefits for the project.
“Partnership is really important because as you enter several distinct markets and geographies, your partner has to work with you to solve for optimal value creation in each of those unique markets,” says EDFR’s Wood. “You need everyone involved to get to that optimal design.”
For EDF Renewables, that means collaborating early with EPCs like Blattner and manufacturers like Nextracker on design, engineering, and pre-construction activities. For its part, Nextracker applies project and performance engineering experience to arrive at the right solution for each project’s terrain, module selection, weather conditions, and to optimally balance CAPEX and OPEX considerations.
“We have structural engineers on our team who can design the foundations for projects, we’re looking at soil conditions to understand pier locations and heights, as well as design considerations based on whether modules are thin-film, large format, or bifacial,” says Cooke. “We also have an arm of the team looking at performance engineering and how to use TrueCapture software to maximize performance.”
While successful partnerships require technical and engineering expertise, they also need trust and strong communication. To Evan Nichols, application engineer at thin-film module manufacturer First Solar, Nextracker’s ability to guide and navigate these discussions is essential.
“When you get into the actual building of these projects, you have to have this complicated discussion between the customer, the structure provider, and the EPC,” says Nichols. “So when we talk about supplying product to a project, that project needs to be receiving the correct module, the correct structure, and it needs to be communicated effectively to the EPC. One of the great things about Nextracker is their ability to work with us and communicate to the EPC so the project gets executed right.”
It is important to highlight that design decisions made upstream in module design such as glass thickness, large cell trends that are implemented to save cost on silicon wafers and module dimensions, all have a ripple effect for the rest of the players in the value chain. Solid working relationships with partners like Nextracker gives the industry a feedback loop to help ensure when design changes are implemented it unlocks value downstream and not just for one player.
As just one example Nichols points to the speed slot design and Nextracker’s speed clips. “Our speed slots design on Series 6 was intentionally shifted from the bottom of our frame to the side, which allows for a more efficient use of frame material and unlocked the capability for Nextracker to develop the speed clips. This in turn helps EPC’s save on labor costs by removing the use of a jig and dramatically increasing module install velocity.”
