Terrain-Following Single-Axis Tracking PV Systems: Civil Work Reduction, Performance Impact, and Lifetime Financial Analysis

Single-axis tracking (SAT) systems have quickly become the most deployed photovoltaic systems at the utility-scale. Conventional SAT systems were designed originally for flat and semi-flat terrain, utilize a straight torque tube around which the modules rotate. However, availability of as flat and semi-flat terrain continues to dwindle, PV system developers are looking to utilize increase undulating land for development. In undulating conditions, conventional SAT systems require either additional grading to level the terrain or a variably adjusted pile height along the tracker to maintain a straight torque tube. However, both approaches incur high costs—either from increased civil work or the additional steel required for piers. As an alternative, terrain-following trackers have been introduced, allowing the tracker to adapt to the natural terrain while maintaining consistent pier heights. While this can induce significant cost savings, the nominal concern with terrain-following systems is the potential for increased electrical mismatch due to variations in the angle of incidence (AOI) across a string, as well as the risk of higher shading losses. Any performance loss will lead to decreased lifetime revenue, a contrasting financial force to the civil work savings incurred in a terrain-following system. While this performance loss has previously been studied in synthetic conditions, we are extending this analysis to a real selection of SAT sites in this work. We have paired this performance analysis with an evaluation of the reduction in civil work at the same set of sites. Using a real-site case study structure, a variety of site conditions were analyzed, seeking to quantify the financial impacts of both the reduction in civil work and the potential performance loss due to terrain-following trackers. Across this selection of sites, the use of terrain-following trackers reduced the need for civil work by an average of over 80%, constituting a significant benefit to the developer of the PV system. In contrast, even the most significant performance loss was just 0.65%, contributing to a minimal impact on lifetime revenue. As a result, across all sites in the selection, the use of terrain-following tracking systems had a positive financial impact, reducing the levelized cost of energy (LCOE) by up to 1.51$/MWh.