Maximizing Tracker Solutions for DG Projects
- Jun 29, 2022 10:23 pm GMT
This item is part of the DER and Management Systems - June 2022 SPECIAL ISSUE, click here for more
As the push for renewable resources grows across the globe, the demand for solar energy market solutions continues to expand. Since large-scale solar installations are not possible everywhere, this means that small-scale utility, and Distributed Generation (DG) projects must be considered too. More and more regions are seeing the value in distributed PV for improved reliability and reduced costs of energy. Many states, particularly in PJM and North-East (NE) territory, are initiating programs and taking advantage of federal incentives to reach their renewable targets. Over the next 4 years, the global DG ground mount solar market is expected to reach $4100M USD. That is roughly 30-40GW of installed capacity and a 6.5% growth since 2020. However, finding ideal land for solar in these regions tends to be more challenging. The land is often constrained for space and includes difficult topography and tree cover; challenges that can quickly elevate costs of capital.
When it comes to small scale solar developments (<40MW), fixed investments required to properly prepare the site for construction have a much greater impact on the project. For instance, grading costs on large-scale utility projects are typically lower on a $/cubic yard basis, than for projects under 40MW. Permitting and environmental remediation costs can also be lower for larger projects than for smaller.
Existing site attributes will guide the level of initial investment and next steps needed to prepare a site for construction. Grading and tree removal (timbering) are key considerations, as are retention ponds and SWPPP. Much of the NE is faced with challenging terrain, requiring site grading or a solution that can accommodate undulating conditions. Grading to mimic optimal flat land environments has been the most widely used approach historically. However, site grading can introduce a significant level of additional cost, impacts to schedule, environmental concerns, and revegetation efforts for a given project. In many cases, these additional costs are enough to terminate a potential development.
Just as with utility-scale solar developments, environmental permits are typically necessary to allow for land disturbance. Not only does this add further cost, but the whole process to receive approval can add weeks or even months to the development process.
“You are certainly going to see a lot friendlier reception from the local AHJ, if you are not doing the disturbance” said Tom Kosto at Blue Ridge Power.
Then, getting the appropriate equipment and operators on site to level the field further extends schedules and increases costs. Finally, the adverse effects of grading on SWPPP and revegetation add even more challenges over the course of the build with muddy conditions after rains, and washouts forming on graded slopes.
Alternatively, significant savings to schedule and budget can be realized by selecting a racking technology that is capable of following the natural terrain. Eliminating grading and compacting on small scale projects can improve the civil schedule by ~15-20% and project costs by $0.02/W or more, when considering an average cost of $6 to move a cubic yard of dirt. “There is an abundance of completed projects where a true all-terrain tracker solution could have saved the owners of those projects thousands and thousands of dollars”
In addition to grading, there are also high costs associated with timbering and grubbing. The equipment used for timbering differs from the equipment needed for site grading, which means that even more heavy equipment must be transported to site, unloaded, stored, serviced, operated, and then taken away. In an ideal situation, both grading and timbering can be removed from site preparation. Luckily, it is a much easier task with smaller sites to identify land that does not have forestry throughout, or around the perimeter, such as farmland or reclaimed coal mines.
With the steady increase of expected capacity for DG development in the pipeline, the industry is in need of tracker providers who are willing and capable of properly supporting DG developments and their related land characteristics. “A lot of DG projects are still going fixed, and that’s because owners can’t justify the cost of all the grading for the tracker.” The best solution is to utilize tracker technology that can operate optimally on all-terrain environments by following the natural terrain. However, there are differences in the design process required for non-flat vs. flat land. In order to accurately design for tracker projects on non-flat terrain, the site-specific layout with the corresponding point file, detailing the foundation locations, is used to optimize each of the variable structural components within the site. With tools to properly analyze the site topography, the net angle change at each foundation can be identified allowing for the selection of appropriate bearing types or, if needed, foundation reveal requirement. Similarly, torque tube lengths and sizes can be automatically chosen based on their location and loading within each block. This analysis is imperative for non-flat terrain projects as wind loads often vary across different slopes. Lastly, foundation placement along the length of each row should be carefully considered on non-flat terrain. Northing distances decrease with increasing slope, which can be accounted for in 3D Civil CAD programs. Once this analysis is complete, a detailed visual of the layout can be created to display each of the individual components used at each point of interest. These outputs are useful not only for the preliminary design work, but also for install teams to effectively plan and stage the site.
Is it not uncommon for tracker providers to opt to pursue larger scale projects as economies of scale make it more advantageous to go this route. However, with the right tools, technology, and partnerships in place from a solar tracker supplier, the lift to go to multiple smaller projects may not actually be too taxing. Further, the more DG sites a developer can prepare for construction at the same time, the greater their purchasing power. Finding the best products to enable low-cost and fast construction can help close more projects to realize increased economies of scale and better margins on projects. At Nevados, we are deploying true all-terrain tracker technology with the goal for our system to never be the limiting factor on challenging terrain. We are opening up new site possibilities for trackers and bringing back sites that were once discarded.
 (2020, July 7). DG Ground-mounted Solar PV Market Insights 2022. 360 Research Reports. https://www.360researchreports.com/global-dg-ground-mounted-solar-pv-mar...
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